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Eng. Proc., 2023, IECB 2023

The 3rd International Electronic Conference on Biosensors

Online | 8–21 May 2023

Volume Editors:
Giovanna Marrazza, University of Florence, Italy
Sara Tombelli, CNR-IFAC, Italy
Benoît Piro, University Paris Diderot, France
Eden Morales-Narváez, National Autonomous University of Mexico, Mexico
Danila Moscone, Università degli Studi di Roma Tor Vergata, Italy
Michael G. Weller, Federal Institute for Materials Research and Testing (BAM), Germany
Shaopeng Wang, Arizona State University, USA

Number of Papers: 40
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Cover Story (view full-size image): This volume presents a collection of contributions at the 3rd International Electronic Conference on Biosensors held on 8–21 May 2023. Biosensors currently have an enormous range of [...] Read more.
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205 KiB  
Editorial
Statement of Peer Review
Eng. Proc. 2023, 35(1), 40; https://doi.org/10.3390/engproc2023035040 - 05 Sep 2023
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Abstract
In submitting conference proceedings to Engineering Proceedings, the volume editors of the proceedings certify to the publisher that all papers published in this volume have been subjected to peer review administered by the volume editors [...] Full article
(This article belongs to the Proceedings of The 3rd International Electronic Conference on Biosensors)

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2524 KiB  
Proceeding Paper
Self-Assembled Monolayers for Uricase Enzyme Absorption Immobilization on Screen-Printed Gold Electrodes Modified
Eng. Proc. 2023, 35(1), 1; https://doi.org/10.3390/IECB2023-14575 - 08 May 2023
Viewed by 614
Abstract
Miniaturized and integrated devices for fast determination of clinical biomarkers are in high demand in the current healthcare environment. In this work, we present a functionalized self-assembled monolayer (SAM) on the gold surface of a screen-printed electrode (Au-SPE). The device was applied for [...] Read more.
Miniaturized and integrated devices for fast determination of clinical biomarkers are in high demand in the current healthcare environment. In this work, we present a functionalized self-assembled monolayer (SAM) on the gold surface of a screen-printed electrode (Au-SPE). The device was applied for uric acid (UA) detection, a biomarker associated with arthritis, diabetes mellitus, and kidney function. Prior to SAM formation, AuSPE was subjected to pretreatment with KOH and Au electrodeposition to provide additional roughness to the substrate. The SAM was formed in the AuSPE/KOH/AuNP surface by the cysteamine method—carried out for working surface dipping in the cysteamine (CYS) solution at 20 mM for 24 h (rinsed with ethanol and milli-Q water). Then, the uricase enzyme was immobilized through physical absorption at room temperature for 1 h to obtain the AuSPE/KOH/AuNPs/SAM/Uox biosensor. The physical and electrochemical characterization of AuSPE modification was carried out by scanning electron microscopy (SEM) and cyclic voltammetry (CV). The calibrated data of the Au/KOH/AuNPs/SAM/Uox biosensor showed a linear relation in the range of 50–1000 µM, a sensibility of 0.1449 µA/[(µM)cm2], and a limit of detection (LOD) of 4.4669 µM. The Au/KOH/AuNPs/SAM/Uox also exhibited good selectivity for UA in the presence of ascorbic acid. Moreover, the methodology showed good reproducibility, stability, and sensitive detection of UA. This performance of the proposed biosensor is in good accordance with clinical needs and can be compared with previous biosensors based on nanostructured surfaces of high-fabrication complexity. Full article
(This article belongs to the Proceedings of The 3rd International Electronic Conference on Biosensors)
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1083 KiB  
Proceeding Paper
Novel Electrochemical Lactate Biosensors Based on Prussian Blue Nanoparticles
Eng. Proc. 2023, 35(1), 2; https://doi.org/10.3390/IECB2023-14572 - 08 May 2023
Cited by 1 | Viewed by 827
Abstract
We report on the novel electrochemical lactate biosensors based on Prussian blue nanoparticles. The immobilization of lactate oxidase was performed through drop-casting on the sensor surface of a mixture containing enzyme, (3-aminopropyl)triethoxysilane and isopropyl alcohol. The apparent Michaelis constant and inactivation constant were [...] Read more.
We report on the novel electrochemical lactate biosensors based on Prussian blue nanoparticles. The immobilization of lactate oxidase was performed through drop-casting on the sensor surface of a mixture containing enzyme, (3-aminopropyl)triethoxysilane and isopropyl alcohol. The apparent Michaelis constant and inactivation constant were determined (0.29 ± 0.03 mM and 0.042 ± 0.002 min−1, respectively) and compared with values obtained for biosensors based on Prussian blue films. The developed lactate biosensors are not inferior in characteristics to those previously known, while the manufacturing process is less laborious. Obtained values also indicate that lactate biosensors based on Prussian blue nanoparticles and lactate oxidase have sufficient sensitivity and operational stability for analytical application in medical and biological research. Full article
(This article belongs to the Proceedings of The 3rd International Electronic Conference on Biosensors)
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1691 KiB  
Proceeding Paper
Assessment of the Freshness of Fish and Poultry Meat by Fast Protein and Metabolite Liquid Chromatography Using a New Optical Sensor
Eng. Proc. 2023, 35(1), 3; https://doi.org/10.3390/IECB2023-14565 - 08 May 2023
Viewed by 836
Abstract
Fresh fish and poultry meat are in high demand on the market: poultry, mainly chicken, is the second most consumed and the most affordable meat product in the world. Fish consumption varies greatly across regions but, in some countries, seafood is the main [...] Read more.
Fresh fish and poultry meat are in high demand on the market: poultry, mainly chicken, is the second most consumed and the most affordable meat product in the world. Fish consumption varies greatly across regions but, in some countries, seafood is the main source of abundant and affordable macro- and micronutrients. Meat and, especially, fish are highly perishable products; methods and equipment for rapid, objective, and reliable assessing the freshness of fish and meat are crucial for the food industry. Generally recognized reference techniques such as total volatile basic nitrogen (TVB-N), volatile fatty acids (VFA), high pressure liquid chromatography (HPLC), mass spectrometry, or nuclear magnetic resonance (NMR) spectroscopy are time-consuming and require expensive and complex equipment. We developed a novel chromatographic optical sensor with a deep UV LED photometric detection (255–265 nm) for rapid assessment of meat and fish freshness based on determination of the relative content of adenosine triphosphate (ATP) metabolites. The sensor has a simple and compact design, and relatively low cost; sample preparation and processing of a chromatogram takes less than 30 min. The sensor was tested on Amur (farmed freshwater fish) and rooster meat, obtained from a local farmer. The samples were kept refrigerated at +4 °C, measurements were taken daily during a 14 day period. All chromatograms show two peaks: proteins are responsible for the first one; the second broad post-protein band is formed due to the overlapping of individual peaks of ATP and its metabolites. As fish and poultry meat are stored, ATP is converted into metabolites with lower molecular weight, which is reflected in the chromatograms—the elution time for the second peak increases. It was shown that this time can be directly associated with the freshness status of a product. As expected, poultry meat showed better storage stability and freshness retention compared to Amur fish. Full article
(This article belongs to the Proceedings of The 3rd International Electronic Conference on Biosensors)
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1064 KiB  
Proceeding Paper
A Cell-Based Bioelectric Biosensor for Salmonella spp. Detection in Food
Eng. Proc. 2023, 35(1), 4; https://doi.org/10.3390/IECB2023-14564 - 08 May 2023
Cited by 2 | Viewed by 476
Abstract
The prevalence of foodborne diseases is continuously increasing, causing numerous hospitalizations and deaths, as well as money loss in the agri-food sector and food supply chain worldwide. The standard analyses currently used for bacteria detection have significant limitations with the most important being [...] Read more.
The prevalence of foodborne diseases is continuously increasing, causing numerous hospitalizations and deaths, as well as money loss in the agri-food sector and food supply chain worldwide. The standard analyses currently used for bacteria detection have significant limitations with the most important being their long procedural time that can be crucial for foodborne outbreaks. In this study, we developed a biosensor system able to perform robust and accurate detection of Salmonella spp. in meat products after a 3-min analysis. To achieve this, we used a portable device developed by EMBIO Diagnostics called B.EL.D (Bio Electric Diagnostics) and a cell-based biosensor technology (BERA). Results indicated that the new method could detect the pathogen within 24 h after a 3-min analysis and discriminate samples with and without Salmonella with high accuracy (86.1%). The method’s sensitivity, specificity, and positive and negative predictive values ranged from 80 to 90.5%, while the limit of detection was determined to be as low as 10 CFU g−1 in all food substrates. Full article
(This article belongs to the Proceedings of The 3rd International Electronic Conference on Biosensors)
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5 pages, 696 KiB  
Proceeding Paper
Detection of Adulteration of Milk from Other Species with Cow Milk through an Immersible Photonic Immunosensor
Eng. Proc. 2023, 35(1), 5; https://doi.org/10.3390/IECB2023-14582 - 05 Jun 2023
Cited by 2 | Viewed by 585
Abstract
Cow milk is more allergenic than milk from other species, and therefore the adulteration of ewe or goat milk with cow milk can pose a serious threat to consumers. In this work, a silicon-based photonic immunosensor, which includes two U-shaped Mach–Zehnder Interferometers (MZIs), [...] Read more.
Cow milk is more allergenic than milk from other species, and therefore the adulteration of ewe or goat milk with cow milk can pose a serious threat to consumers. In this work, a silicon-based photonic immunosensor, which includes two U-shaped Mach–Zehnder Interferometers (MZIs), was employed for the detection of ewe and goat milk adulteration with cow milk through the immunochemical determination of the milk. The method was fast and sensitive with a detection limit of 0.04 μg/mL bovine k-casein (which corresponds to approximately 0.06% cow milk) in ewe or goat milk, respectively, and with a total assay time of 12 min. Full article
(This article belongs to the Proceedings of The 3rd International Electronic Conference on Biosensors)
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3497 KiB  
Proceeding Paper
Types of EMG Textile Electrodes: A Comparative Study Using PCA
Eng. Proc. 2023, 35(1), 6; https://doi.org/10.3390/IECB2023-14560 - 08 May 2023
Viewed by 923
Abstract
Identifying a suitable textile electrode that would be durable and assist in recording high-quality bio-signal quality is crucial in the production of medical devices. Therefore, this study is aimed at comparing the time domain characteristics of silver-plated-polyamide-embroidered cotton (SPEC), copper-nickel-plated polyester (CNP), and [...] Read more.
Identifying a suitable textile electrode that would be durable and assist in recording high-quality bio-signal quality is crucial in the production of medical devices. Therefore, this study is aimed at comparing the time domain characteristics of silver-plated-polyamide-embroidered cotton (SPEC), copper-nickel-plated polyester (CNP), and stainless-steel-fabric (SSF) dry textile electromyography (EMG) electrodes through principal component analysis (PCA). The standard silver/silver chloride (Ag/AgCl) gel electrode was considered as the reference for all the test textile electrodes mentioned above. The EMG signal was measured by activation of the bicep and tibialis anterior muscles, and the time domain features such as root mean square (RMS) voltage, average rectified value (ARV) voltage, signal to noise ratio (SNR), kurtosis, and skewness were extracted from the EMG signal. The SSF electrode outperformed CNP and SPEC electrodes. Each textile electrode exhibited signal-to-noise ratio (SNR) values comparable to that of the standard electrode. The SNR values were 24.38 dB, 17.72 dB, 15.55 dB, and 13.30 dB for Ag/AgCl, SSF, CNP and SPEC electrodes, respectively. The performance of all the conductive textile electrodes was comparable to that of Ag/AgCl. However, the gel electrode required skin preparation and exhibited short-term stability, whereas, textile electrode materials were long-lasting and could be used for biological signal monitoring at home without the assistance of medical professionals. Full article
(This article belongs to the Proceedings of The 3rd International Electronic Conference on Biosensors)
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1595 KiB  
Proceeding Paper
Immunosensing Cancer Markers through Surface-Enhanced Photoluminescence on Nanostructured Silver Substrates
Eng. Proc. 2023, 35(1), 7; https://doi.org/10.3390/IECB2023-14583 - 08 May 2023
Viewed by 851
Abstract
Noble metal nanostructured substrates enhance photoluminescence emitted from molecules immobilized onto their surface, allowing for the development of highly sensitive immunoassays employing fluorescent labels. In this work, nanostructured silver surfaces were implemented as substrates for the immunochemical detection of two ovarian cancer markers, [...] Read more.
Noble metal nanostructured substrates enhance photoluminescence emitted from molecules immobilized onto their surface, allowing for the development of highly sensitive immunoassays employing fluorescent labels. In this work, nanostructured silver surfaces were implemented as substrates for the immunochemical detection of two ovarian cancer markers, carbohydrate antigen 125 (CA125) and human epididymis protein 4 (HE4). Biotinylated detection antibodies were used to allow for the detection of immunocomplexes through a reaction with streptavidin conjugated to Rhodamine Red-X. The detection limits achieved were 2.5 U/mL and 0.06 ng/mL for CA125 and HE4, respectively, with linear dynamic ranges, covering the concentration ranges of both healthy and ovarian cancer patients. Full article
(This article belongs to the Proceedings of The 3rd International Electronic Conference on Biosensors)
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1359 KiB  
Proceeding Paper
A Novel Dielectric Modulated Misaligned Double-Gate Junctionless MOSFET as a Label-Free Biosensor
Eng. Proc. 2023, 35(1), 8; https://doi.org/10.3390/IECB2023-14578 - 08 May 2023
Cited by 2 | Viewed by 518
Abstract
This research paper presents a misaligned double-gate junctionless Metal-Oxide-Semiconductor Field-Effect Transistor for label-free detection of biomolecules. The proposed biosensor combines the advantages of being junctionless, as well as possessing double and misaligned gate MOSFETs, which results in improved sensitivity and selectivity for biological [...] Read more.
This research paper presents a misaligned double-gate junctionless Metal-Oxide-Semiconductor Field-Effect Transistor for label-free detection of biomolecules. The proposed biosensor combines the advantages of being junctionless, as well as possessing double and misaligned gate MOSFETs, which results in improved sensitivity and selectivity for biological recognition. The results show that the proposed biosensor can effectively detect biomolecules and has the potential for use in various applications. Biosensors have become an important tool in various fields, such as healthcare, environmental monitoring, and food safety due to their ability to detect biomolecules. MOSFETs have been widely used as biosensors due to their less complex structure and ease of use. However, traditional MOSFETs have limitations in terms of sensing performance, and there is a need for improved designs that overcome these limitations. The results of this study show that the proposed biosensor can effectively detect various biomolecules, such as protein and DNA. The proposed biosensor design has the potential to revolutionize the field of biosensors. Its combination of improved sensitivity and selectivity makes it a valuable tool for various applications. In conclusion, this research paper presents a dielectric modulated novel misaligned double-gate junctionless MOSFET-based biosensor, promising improved sensing performance in various applications. The proposed design provides a valuable contribution to the field of biosensors and has the potential to revolutionize the way biomolecules are detected. Full article
(This article belongs to the Proceedings of The 3rd International Electronic Conference on Biosensors)
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2141 KiB  
Proceeding Paper
Preliminary Results of the Development of a DNA-Hybridization-Based Biosensor for the Detection of Milk Adulteration Using Gold Interdigitated Electrodes
Eng. Proc. 2023, 35(1), 9; https://doi.org/10.3390/IECB2023-14567 - 08 May 2023
Viewed by 437
Abstract
Milk is a widely consumed product, and its adulteration is not only common but also very dangerous. This study aimed to develop a biosensor for the detection of milk adulteration using DNA hybridization coupled with an electrochemical device. The advantages of biosensors over [...] Read more.
Milk is a widely consumed product, and its adulteration is not only common but also very dangerous. This study aimed to develop a biosensor for the detection of milk adulteration using DNA hybridization coupled with an electrochemical device. The advantages of biosensors over traditional laboratory methods, such as their speed, ease of use, and cost-effectiveness, are combined with the sensitivity of DNA hybridization. A capacitive biosensor was developed using interdigitated gold electrodes on paper substrate, which were modified with specific oligonucleotides for cow mitochondrial DNA that served as the biorecognition element. The methodology relies on the measurement of changes in capacitance due to DNA hybridization. Preliminary results are presented, showing the ability of this biosensor to detect bovine DNA in goat milk with high sensitivity and specificity. The results show that this biosensor has the potential to be a low-cost, easy-to-perform, and fast method for the detection of milk adulteration. This biosensor technology is a promising development for the detection of milk adulteration and can help to ensure the safety and quality of milk products. Full article
(This article belongs to the Proceedings of The 3rd International Electronic Conference on Biosensors)
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641 KiB  
Proceeding Paper
Micro-Weighing Based Biosensor with Adaptive Interferometry
Eng. Proc. 2023, 35(1), 10; https://doi.org/10.3390/IECB2023-14570 - 08 May 2023
Viewed by 412
Abstract
In this work, an adaptive holographic interferometer was implemented for the measurement of a micromechanical oscillator frequency. A silicon micro-cantilever mounted on a piezoquartz plate was used as the sensing element. Out-of-plane vibrations of the cantilever were excited using a sinusoidal electrical signal. [...] Read more.
In this work, an adaptive holographic interferometer was implemented for the measurement of a micromechanical oscillator frequency. A silicon micro-cantilever mounted on a piezoquartz plate was used as the sensing element. Out-of-plane vibrations of the cantilever were excited using a sinusoidal electrical signal. The cantilever vibrations were measured with the adaptive interferometer using two waves coupling in a semi-insulating photorefractive CdTe:V crystal. In the experiment, the mass of absorbed molecules of bovine serum albumin (BSA) was measured at various concentrations of water solution. The biosensor demonstrated the ability to measure the concentration of BSA in water solutions with a concentration of 0.2 mg/mL. The result shows the possibility of using adaptive interferometry to detect the vibration of micromechanical sensors and the potential prospects for building biosensors based on them. Full article
(This article belongs to the Proceedings of The 3rd International Electronic Conference on Biosensors)
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1051 KiB  
Proceeding Paper
Hydrogel-Coated Nanonet-Based Field-Effect Transistors for SARS-CoV-2 Spike Protein Detection in High Ionic Strength Samples
Eng. Proc. 2023, 35(1), 11; https://doi.org/10.3390/IECB2023-14566 - 08 May 2023
Cited by 1 | Viewed by 555
Abstract
The SARS-CoV-2 pandemic has triggered many studies worldwide in the area of biosensors, leading to innovative approaches for the quantitative assessment of COVID-19. A nanostructured field-effect transistor (FET) is one type of device shown to be ultrasensitive for virus determination. FETs can be [...] Read more.
The SARS-CoV-2 pandemic has triggered many studies worldwide in the area of biosensors, leading to innovative approaches for the quantitative assessment of COVID-19. A nanostructured field-effect transistor (FET) is one type of device shown to be ultrasensitive for virus determination. FETs can be used as transducers to analyze changes in electrical current caused by the bonding of viral molecules to the surface of the semiconducting nanomaterial layer of the FETs. Although nano-transistors require simple setups amenable to be miniaturized for point-of-care diagnostic of COVID-19, this type of sensor usually has limited sensitivity in biological fluids. The reason behind this is the shortened screening length in the presence of high ionic strength solutions. In the frame of this study, we propose a methodology consisting of the FET surface modification with a hydrogel based on the star-shaped polyethylene glycol (starPEG), which hosts specific antibodies against SARS-CoV-2 spike protein in its porous structure. The deposition of the hydrogel increases the effective Debye length, preserving the biosensor’s sensitivity. We demonstrate the capability of silicon nanonet-based FETs to detect viral antigens and cultured viral particles in phosphate-buffered saline (PBS) as well as in human-purified saliva. Finally, we discriminated between positive and negative patients’ nasopharyngeal swab samples. Full article
(This article belongs to the Proceedings of The 3rd International Electronic Conference on Biosensors)
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7 pages, 1823 KiB  
Proceeding Paper
Wearable and Smartphone-Based Sensors in Support of Human-Comfort-Driven Structural Analysis of Building Components
Eng. Proc. 2023, 35(1), 12; https://doi.org/10.3390/IECB2023-14586 - 09 May 2023
Viewed by 383
Abstract
The continuous progress and advancement of innovation in technology and development of digital tools makes modern structural engineers and technicians of the building and construction sector increasingly able to solve a multitude of design issues. In most of cases, they can take advantage [...] Read more.
The continuous progress and advancement of innovation in technology and development of digital tools makes modern structural engineers and technicians of the building and construction sector increasingly able to solve a multitude of design issues. In most of cases, they can take advantage of, and support from, low-cost and even portable sensors characterized by generally medium-high accuracy and commercial availability. In this paper, the attention is focused on the analysis of recent investigations which have been carried out within the scope of human-comfort-driven structural analysis and design of building components. More precisely, the use of wearable and smartphone-based sensors for the experimental derivation of mechanical parameters of utmost importance and technical interest for the design of pedestrian systems is explored. On the one hand, as shown, the elaborated setup makes it fast and easy to acquire body motion parameters for pedestrians moving on different substructures. At the same time, relevant feedback could possibly be obtained from customers on their corresponding comfort. Full article
(This article belongs to the Proceedings of The 3rd International Electronic Conference on Biosensors)
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4 pages, 775 KiB  
Proceeding Paper
Functionalization of Graphene Oxide for Label-Free Electrochemical Detection of Hepatic Cancer Cells
Eng. Proc. 2023, 35(1), 13; https://doi.org/10.3390/IECB2023-14599 - 12 May 2023
Viewed by 628
Abstract
In this study, a graphene oxide-modified screen-printed carbon electrode was functionalized with the 1-pyrenebutyric acid-N-hydroxy-succinimide ester and conjugated with antibodies for the label-free detection of human hepatoma HepG2 cells. Using a user-friendly reservoir chamber, the functionalized film was exposed continuously to the cancer [...] Read more.
In this study, a graphene oxide-modified screen-printed carbon electrode was functionalized with the 1-pyrenebutyric acid-N-hydroxy-succinimide ester and conjugated with antibodies for the label-free detection of human hepatoma HepG2 cells. Using a user-friendly reservoir chamber, the functionalized film was exposed continuously to the cancer cells. The use of a continuous flow was intended to enhance the capture of the target cells by the sensing platform. The response of the biosensor was evaluated using cyclic voltammetry. The preliminary data showed good sensitivity for the detection of hepatic cancer cells. The developed biosensor could detect the HepG2 cells from a 1 × 103 to 3 × 105 cells/mL range. Thus, it is a simple tool for the electrochemical detection of cancer cells and offers a low-cost and disposable sensing platform. Full article
(This article belongs to the Proceedings of The 3rd International Electronic Conference on Biosensors)
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1000 KiB  
Proceeding Paper
Cell Classification Based on Artificial Intelligence Analysis of Cell Images in Microfluidic Chip
Eng. Proc. 2023, 35(1), 14; https://doi.org/10.3390/IECB2023-14569 - 08 May 2023
Viewed by 576
Abstract
We developed a low-cost, multi-classification, label-free and high-precision method for cell classification, which combines microfluidic technology with a deep learning algorithm. The recognition of the states of red blood cells was selected as a typical example to demonstrate the feasibility of the method. [...] Read more.
We developed a low-cost, multi-classification, label-free and high-precision method for cell classification, which combines microfluidic technology with a deep learning algorithm. The recognition of the states of red blood cells was selected as a typical example to demonstrate the feasibility of the method. The microfluidic channel is designed to effectively and controllably solve the problem of cell overlap, which has a severe negative impact on the identification of cells. The object detection model based on YOLOv4 is optimized and used to recognize multiple RBCs simultaneously in the whole field of view, so as to classify them into different morphological subcategories and count the numbers in each subgroup. Full article
(This article belongs to the Proceedings of The 3rd International Electronic Conference on Biosensors)
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2040 KiB  
Proceeding Paper
Contact Lens-Based Intraocular Pressure Sensor
Eng. Proc. 2023, 35(1), 15; https://doi.org/10.3390/IECB2023-14577 - 08 May 2023
Cited by 1 | Viewed by 392
Abstract
The intraocular pressure (IOP) is the principal indicator for diagnosis of glaucoma which is one of the leading causes of blindness. The IOP can vary throughout the day, and traditional methods of measuring it in a clinical setting only provide a fraction of [...] Read more.
The intraocular pressure (IOP) is the principal indicator for diagnosis of glaucoma which is one of the leading causes of blindness. The IOP can vary throughout the day, and traditional methods of measuring it in a clinical setting only provide a fraction of the patient’s IOP pattern. This article presents a cost-effective way for continuous monitoring of IOP by utilizing a soft contact lens with strategically placed holes. The deformation of these holes due to the change in IOP can be used to detect the pressure variations throughout the day. Extensive COMSOL Multiphysics simulations are conducted to optimize the design and to test the viability of this method. The optimized lens design can achieve a large deformation ratio sensitivity of 0.39 per mmHg with an applied pressure range of 10 mmHg to 40 mmHg. Full article
(This article belongs to the Proceedings of The 3rd International Electronic Conference on Biosensors)
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1494 KiB  
Proceeding Paper
Ag/TiO2 Nanocomposites for Nanothermometry in the Biological Environment
Eng. Proc. 2023, 35(1), 16; https://doi.org/10.3390/IECB2023-14585 - 08 May 2023
Cited by 1 | Viewed by 433
Abstract
Local temperature determination is essential to understand heat transport phenomena at the nanoscale and to design nanodevices for biomedical, photonic, and optoelectronic applications. In particular, the detection of the local temperature of the intracellular environment is interesting for photothermal therapy. In the present [...] Read more.
Local temperature determination is essential to understand heat transport phenomena at the nanoscale and to design nanodevices for biomedical, photonic, and optoelectronic applications. In particular, the detection of the local temperature of the intracellular environment is interesting for photothermal therapy. In the present work, nanoparticles consisting of an Ag core, covered by a TiO2 shell and Ag@TiO2 core–shell, were suitably synthesized through a one-pot method. Silver nanoparticles synthesized in DMF were coated by controlled hydrolysis of titanium tetrabutoxide in the same reaction environment. The synthesis led to nanocomposites where AgNPs were covered by a diffuse layer of anatase. The nanocomposites were characterized using UV/Vis spectroscopy and Raman spectroscopy. The samples obtained proved to be good Raman nanothermometers with a sensitivity comparable to that of simple anatase nanoparticles. Full article
(This article belongs to the Proceedings of The 3rd International Electronic Conference on Biosensors)
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870 KiB  
Proceeding Paper
Nanoparticle/DNAzyme Based Biosensors for Heavy-Metal Ion Detection: Effect of DNAzyme Surface Modifications on Device Sensitivity
Eng. Proc. 2023, 35(1), 17; https://doi.org/10.3390/IECB2023-14581 - 08 May 2023
Viewed by 614
Abstract
In this work, a biosensor for heavy metal-ion detection, based on platinum nanoparticles (Pt NPs) and DNAzymes, is presented. Two chemical modification groups were utilized for the DNAzymes’ immobilization on the Pt NPs film. The biosensors were characterized concerning their ability to detect [...] Read more.
In this work, a biosensor for heavy metal-ion detection, based on platinum nanoparticles (Pt NPs) and DNAzymes, is presented. Two chemical modification groups were utilized for the DNAzymes’ immobilization on the Pt NPs film. The biosensors were characterized concerning their ability to detect Lead (Pb2+) ions in buffer solutions. Both immobilization techniques exhibit great sensitivity with a detection limit of 25 nM. Full article
(This article belongs to the Proceedings of The 3rd International Electronic Conference on Biosensors)
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1623 KiB  
Proceeding Paper
Biodegradable Mats for the Design of Bifunctional Biosensors for Glucose Detection in Urine
Eng. Proc. 2023, 35(1), 18; https://doi.org/10.3390/IECB2023-14580 - 08 May 2023
Viewed by 553
Abstract
We introduce a bifunctional architecture to construct biosensors on solution-blow spinning fiber mats of polylactic acid (PLA) and polyethylene glycol (PEG). PLA/PEG mats acted as substrate for printing electrodes and as matrix to immobilize glucose oxidase (GOx). Prussian Blue nanoparticles (PB) decorated working [...] Read more.
We introduce a bifunctional architecture to construct biosensors on solution-blow spinning fiber mats of polylactic acid (PLA) and polyethylene glycol (PEG). PLA/PEG mats acted as substrate for printing electrodes and as matrix to immobilize glucose oxidase (GOx). Prussian Blue nanoparticles (PB) decorated working electrodes to detect H2O2 from enzymatic catalysis at a low applied potential (0 V vs. Ag/AgCl) with detection limit of 0.197 mM. The inexpensive bifunctional device (<US $0.25 per unit) exhibited a rapid response, long lifetime, and performance similar to the standard method for glucose monitoring in human urine samples. The PLA/PEG mats are sustainable alternative for biosensing and wearable applications. Full article
(This article belongs to the Proceedings of The 3rd International Electronic Conference on Biosensors)
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7 pages, 1092 KiB  
Proceeding Paper
Electrochemistry of Freely Diffusing Mediators in Polyelectrolyte Membranes Used for Blood Glucose Test Strips with a High Upper Limit of the Linear Range
Eng. Proc. 2023, 35(1), 19; https://doi.org/10.3390/IECB2023-14603 - 16 May 2023
Viewed by 400
Abstract
Co-immobilization of low-molecular-weight mediators and glucose oxidase in polyelectrolyte membranes results in glucose test strips operating in the millimolar concentration range. The density and charge of polyelectrolyte membranes formed on the surface of the screen-printed electrodes allow the diffusion of mediators to be [...] Read more.
Co-immobilization of low-molecular-weight mediators and glucose oxidase in polyelectrolyte membranes results in glucose test strips operating in the millimolar concentration range. The density and charge of polyelectrolyte membranes formed on the surface of the screen-printed electrodes allow the diffusion of mediators to be controlled. Negatively charged perfluorosulfonated ionomer (PFSI) hampers the diffusion of the commonly used ferricyanide (III) ion, while the hexammine ruthenium (III) cation apparent diffusion coefficient in PFSI membrane remains the same as without the membrane. In contrast to PFSI, electrode modification with positively charged chitosan leads to additional adsorption of potassium hexacyanoferrate on the membrane. Additionally, the rate of mediator leakage from the membrane was found to govern the sensitivity of the resulting biosensors. The leakage rate also depends on the density and charge of the polyelectrolyte and mediator. However, the main advantage of the proposed simple approach of single-step deposition of three-component membrane-forming mixtures on the screen-printed electrodes is the extended upper limit of the linearity: 30–50 mM glucose. Hence, the obtained test strips are suitable for glucose detection in undiluted blood. Full article
(This article belongs to the Proceedings of The 3rd International Electronic Conference on Biosensors)
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2020 KiB  
Proceeding Paper
Directed Evolution of a Genetically Encoded Bioluminescent Ca2+ Sensor
Eng. Proc. 2023, 35(1), 20; https://doi.org/10.3390/IECB2023-14563 - 08 May 2023
Viewed by 537
Abstract
The use of genetically encoded fluorescent sensors for the calcium ion (Ca2+) has revolutionized neuroscience research by allowing for the recording of dozens of neurons at the single-cell level in living animals. However, fluorescence imaging has some limitations such as the [...] Read more.
The use of genetically encoded fluorescent sensors for the calcium ion (Ca2+) has revolutionized neuroscience research by allowing for the recording of dozens of neurons at the single-cell level in living animals. However, fluorescence imaging has some limitations such as the need for excitation light, which can result in a highly auto-fluorescent background and phototoxicity. In contrast, bioluminescent sensors using luciferase do not require excitation light, making them ideal for non-invasive deep tissue imaging in mammals. Our lab has previously developed a bioluminescent Ca2+ sensor CaMBI to image Ca2+ activity in the mouse liver, but its responsiveness to Ca2+ changes was suboptimal. To improve the performance of this sensor, we applied directed evolution to screen for genetic variants with increased responsiveness. Through several rounds of evolution, we identified variants with more than five times improved responsiveness in vitro. We characterized the improved sensors in culture cell lines and dissociated rat neurons and confirmed that they exhibited a higher sensitivity to changes in intracellular Ca2+ levels compared to their progenitor. These optimized Ca2+ sensors have the potential for non-invasive imaging of Ca2+ activity in vivo, particularly in the brain. Full article
(This article belongs to the Proceedings of The 3rd International Electronic Conference on Biosensors)
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8 pages, 13029 KiB  
Proceeding Paper
In Silico Analysis of Toehold-Aptamer Sequences Targeting the SARS-CoV-2 Nucleocapsid Protein Gene for Biosensor Development
Eng. Proc. 2023, 35(1), 21; https://doi.org/10.3390/IECB2023-14718 - 23 May 2023
Viewed by 583
Abstract
The COVID-19 pandemic has emphasized the need for rapid and affordable on-site virus detection. While enzyme-linked aptamer-based biosensors have proven effective, their utility for SARS-CoV-2 detection remains unexplored. We performed in silico analysis of three toehold-aptamer sequences targeting the SARS-CoV-2 nucleocapsid protein gene, [...] Read more.
The COVID-19 pandemic has emphasized the need for rapid and affordable on-site virus detection. While enzyme-linked aptamer-based biosensors have proven effective, their utility for SARS-CoV-2 detection remains unexplored. We performed in silico analysis of three toehold-aptamer sequences targeting the SARS-CoV-2 nucleocapsid protein gene, with secondary and tertiary structures modeled using mFold and RNAComposer web servers. Molecular docking simulations were challenging due to computational and molecular constraints. Nevertheless, our findings indicate that experimental procedures to assess aptamer–target interactions in vitro under optimal assay conditions are feasible. Successful development of a biosensor using these aptamers could offer a quick and inexpensive method for SARS-CoV-2 detection, addressing the COVID-19 pandemic. Full article
(This article belongs to the Proceedings of The 3rd International Electronic Conference on Biosensors)
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8 pages, 2434 KiB  
Proceeding Paper
Preliminary Studies on the Synthesis of Redox-Labelled Molecularly Imprinted Nanoparticles in Sensor Development for the Quantification of Perfluoroalkyls in Water
Eng. Proc. 2023, 35(1), 22; https://doi.org/10.3390/IECB2023-14589 - 09 May 2023
Viewed by 480
Abstract
Polyfluoroalkyl compounds (PFASs) are synthetic compounds recently classified as permanent and emerging chemicals ever since their bioaccumulation in humans and the environment, due to the presence of carbon–fluorine functional groups. The design of novel screening tools with addressed high response time for the [...] Read more.
Polyfluoroalkyl compounds (PFASs) are synthetic compounds recently classified as permanent and emerging chemicals ever since their bioaccumulation in humans and the environment, due to the presence of carbon–fluorine functional groups. The design of novel screening tools with addressed high response time for the routine quantification of PFASs in water is highly desirable. In this work, we propose the preparation of a new voltammetric sensor based on molecularly imprinted polymer nanoparticle (nanoMIP) receptors for the highly sensitive and selective quantification of PFASs in water. The nanoMIPs were synthesized by the solid phase approach and immobilized onto functionalized screen-printed platinum electrode (SPPtE), chosen as the transduction element for sensor development. Dimensional characterization of nanoMIPs by Dynamic light scattering (DLS) shows small nanosized imprinted particles (<200 nm) with a polydispersity index (PDI) below 0.3. Electrochemical techniques were used for sensor preparation, characterization, and to assess the analytical performance, respectively. Preliminary calibration curves of nanoMIP-based sensors in a wide range of PFAS concentrations (1.5–100 ng/mL) exhibited high sensitivity toward its target. Full article
(This article belongs to the Proceedings of The 3rd International Electronic Conference on Biosensors)
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1389 KiB  
Proceeding Paper
Adsorbate Induced Transformations of Ovalbumin Layers in Volatile Organic Solvents: QCM Study of a Potential Bio-Sniffer for Acute Toxicity Assays
Eng. Proc. 2023, 35(1), 23; https://doi.org/10.3390/IECB2023-14574 - 08 May 2023
Viewed by 401
Abstract
Acute toxicity data are a necessary component of the general analysis of gaseous environments and the prediction of the possible consequences of exposure to a chemical substance on living organisms. One of the fastest ways to obtain such information is to use gas-phase [...] Read more.
Acute toxicity data are a necessary component of the general analysis of gaseous environments and the prediction of the possible consequences of exposure to a chemical substance on living organisms. One of the fastest ways to obtain such information is to use gas-phase chemical sensors with sensitive layers of biological origin. Here we report an experimental study of complex loadings for classical quartz crystal microbalances arising in closely packed protein layers of ovalbumin (OVA) on the surface of polycrystalline silver, silver coated with rigid carbon fullerene C60, or a soft molecular-organic crystal of copper phthalocyanine (CuPc). OVA molecules are similarly immobilized on the silver and fullerene-decorated surfaces, while the response of the OVA-CuPc layer indicates an insignificant amount of protein on the surface. A systematic study of the kinetics of the responses of these layers to saturated vapors of volatile solvents shows that the QCM resonant frequency change correlates well with the toxicity of gaseous analytes. It has been observed that saturated vapors of water, ethanol, and their mixtures are classically adsorbed with a high adsorption capacity. Benzene and isobutanol showed only a non-monotonic anti-Sauerbrey behavior, while acetone and cyclohexane had a 10-fold smaller quasi-classical response. The possibility of a gaseous analyte changing not only the QCM loading but also the mechanical behavior of the protein mass associated with the surface opens up the possibility of observing nonspecific conformational changes in proteins, which can be the cause of general cytotoxicity. This effect, combined with the native conformation of OVA in densely packed protein films, allows the use of ovalbumin in creating sensitive bio-sniffer layers for fast toxicological assays—a new class of express tests for biosafety and environmental control. Full article
(This article belongs to the Proceedings of The 3rd International Electronic Conference on Biosensors)
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7 pages, 1833 KiB  
Proceeding Paper
Construction of a Miniaturized Monosaccharide Detection System Based on Measuring Electric Current and Testing Its Performance Using a Bodipy Fluorescent Dye
Eng. Proc. 2023, 35(1), 24; https://doi.org/10.3390/IECB2023-14587 - 09 Jun 2023
Viewed by 454
Abstract
In this study, a low-cost, miniaturized fluorescence-based measurement system for optical biosensors has been developed. A 3D-printed setup with a blue light-emitting diode (LED) and photodiode was used for electrical detection and monitoring of fluorescence light intensity. The system was used to explore [...] Read more.
In this study, a low-cost, miniaturized fluorescence-based measurement system for optical biosensors has been developed. A 3D-printed setup with a blue light-emitting diode (LED) and photodiode was used for electrical detection and monitoring of fluorescence light intensity. The system was used to explore the fluorescence quenching of boron-dipyrromethene (Bodipy) in the presence of boronic acid functionalized benzyl viologen (o-BBV) to develop a monosaccharide detection platform by studying at different pHs and temperatures. The results showed that the system has potential for further development and optimization. This study provides a proof-of-concept for a low-cost and miniaturized optical biosensor for monosaccharides. Full article
(This article belongs to the Proceedings of The 3rd International Electronic Conference on Biosensors)
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8 pages, 1321 KiB  
Proceeding Paper
Simple Chromatographic Sensor with UV LED Optical Detection for Monitoring Patients Treated with Continuous Ambulatory Peritoneal Dialysis
Eng. Proc. 2023, 35(1), 25; https://doi.org/10.3390/IECB2023-14595 - 09 Jun 2023
Viewed by 551
Abstract
A novel simple optical sensor based on fast protein liquid chromatography was developed and tested for monitoring end stage renal disease (ESRD) patients treated with continuous ambulatory peritoneal dialysis (CAPD). The device provides direct determination of proteins and lower molecular weight metabolites in [...] Read more.
A novel simple optical sensor based on fast protein liquid chromatography was developed and tested for monitoring end stage renal disease (ESRD) patients treated with continuous ambulatory peritoneal dialysis (CAPD). The device provides direct determination of proteins and lower molecular weight metabolites in effluent peritoneal dialysate using ultraviolet (UV) photometric detection at the wavelengths 285 nm or 260 nm with deep ultraviolet light-emitting diodes. The sensor was calibrated with bovine serum albumin and nucleotides standard solutions. Chromatograms of peritoneal dialysate samples taken from a group of 28 ESRD patients were processed and approximated by a set of split-Gaussian functions. All chromatograms show three overlapping peaks: the first one represents proteins; the other two peaks probably correspond to mid- and low molecular weight metabolites. Strong correlation was reveled between the area of the first peak and total protein concentration determined by a standard biochemical assay, this makes possible estimation of peritoneal protein loss with a reasonable precision less than 15%. The area of the second peak correlated with dialysate optical density at a wavelength 355–365 nm, associated with the UV absorption of advanced glycation end (AGE) products. The third peak correlated with the optical density of the eluate at a wavelength 255–265 nm, associated with the UV absorption of purines and pyrimidines. Thus, we demonstrated the possibility of estimation of proteins and lower molecular weight metabolites in effluent peritoneal dialysate with the compact and affordable chromatographic optical sensor. Full article
(This article belongs to the Proceedings of The 3rd International Electronic Conference on Biosensors)
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8 pages, 6237 KiB  
Proceeding Paper
Biocompatible and Flexible Transparent Electrodes for Skin-Inspired Sensing
Eng. Proc. 2023, 35(1), 26; https://doi.org/10.3390/IECB2023-14588 - 09 Jun 2023
Viewed by 504
Abstract
In recent years, flexible electronics have experienced a massive growth as a response to the high demand for new skin-patch sensor devices targeted at personal health-monitoring. In this context, the incorporation of biopolymers into the backbone of these soft systems brings new opportunities [...] Read more.
In recent years, flexible electronics have experienced a massive growth as a response to the high demand for new skin-patch sensor devices targeted at personal health-monitoring. In this context, the incorporation of biopolymers into the backbone of these soft systems brings new opportunities in terms of biocompatibility and sustainability performance. However, the suitable integration of a conductive patterned material is still a challenge, in order to achieve good adhesion and high transparency. Thus, silver nanowires (AgNWs) constitute promising candidates for the fabrication of flexible transparent conductive films. Herein, a chitosan membrane doped with a plasticizer element was made conductive, through a one-step process, by using an optimized ratio of chitosan–lactic acid–AgNWs (Chi-LaA-AgNWs) dispersion. This formulation was applied using screen-printing, and the influence of the polymer ratio, cure temperature, and number of layers applied with the AgNW-based ink was investigated. Compared with conventional water-based AgNW dispersions, the here-proposed chitosan-doped ink enabled the fabrication of transparent electrode platforms holding good stability, homogeneity, and electrical features. Full article
(This article belongs to the Proceedings of The 3rd International Electronic Conference on Biosensors)
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8 pages, 1588 KiB  
Proceeding Paper
Non-Invasive IR-Based Measurement of Human Blood Glucose
Eng. Proc. 2023, 35(1), 27; https://doi.org/10.3390/IECB2023-14593 - 09 Jun 2023
Cited by 1 | Viewed by 5294
Abstract
Non-Invasive blood glucose monitoring using infrared (IR) light is considered to be a useful and reliable tool for measuring blood sugar levels during daily activities. IR-based glucose monitoring depends on the variant absorption levels of IR light waves by blood with high or [...] Read more.
Non-Invasive blood glucose monitoring using infrared (IR) light is considered to be a useful and reliable tool for measuring blood sugar levels during daily activities. IR-based glucose monitoring depends on the variant absorption levels of IR light waves by blood with high or low levels of glucose solution. This paper introduces a low-cost finger probe to measure glucose based on Arduino and embedding a Clarke error grid with fuzzy logic. An electronic blood glucose meter was designed and implemented in a non-invasive and painless manner based on an infrared sensor. The electrical signal expressing the level of glucose in the blood with a mathematical equation was used to calibrate and map the physical and electrical values. The final numerical value was validated with the Clarke error grid by implementing fuzzy logic (FL). The designed device was tested on 30 subjects with 15 diabetes subjects. The results show the high significance of results at points where the FL was able to determine an error range of less than 10% of measured glucose within the same range of the reference measurements. The proposed method of using FL with a Clarke error grid gives more confident and precise outputs in cases of this kind of portable device. Full article
(This article belongs to the Proceedings of The 3rd International Electronic Conference on Biosensors)
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1288 KiB  
Proceeding Paper
Detection of Pathogens and Antimicrobial Resistance Genes at Low Concentration via Electrochemical Oligonucleotide Tags
Eng. Proc. 2023, 35(1), 28; https://doi.org/10.3390/IECB2023-14584 - 08 May 2023
Viewed by 389
Abstract
Pathogens can be detected electrochemically by measuring guanine oxidation signals generated from RNA or DNA hybridized to a biosensor working electrode. However, the associated limit of detection (LOD) is not sufficiently low for widespread clinical use. Working electrodes employing nanomaterials such as carbon [...] Read more.
Pathogens can be detected electrochemically by measuring guanine oxidation signals generated from RNA or DNA hybridized to a biosensor working electrode. However, the associated limit of detection (LOD) is not sufficiently low for widespread clinical use. Working electrodes employing nanomaterials such as carbon nanotubes successfully reduce the LOD, but nanosensors experience high variability, poor fabrication yield, and high production cost. Our work presented here demonstrates a novel approach for electrochemically detecting low-concentration pathogens and antimicrobial resistance genes that transfers the guanine oxidation source from naturally occurring RNA to synthetic oligonucleotides. In our assay, signal amplification is accomplished by binding RNA from lysed microbial cells to microparticles conjugated with millions of guanine-rich oligonucleotide tags. We employed a sandwich hybridization assay to bind RNA between a screen-printed carbon working electrode conjugated with recognition probes, and a microparticle conjugated with electrochemical oligonucleotide tags. These tags contained a polyguanine detection sequence and an RNA capture sequence on the same oligonucleotide. Single-stranded polyguanine was prefabricated into a quadruplex to enable 8-oxoguanine signals at 0.47 V. This eliminated nonspecific guanine oxidation signals from the RNA, while further reducing the LOD over guanine oxidation. A 70-mer capture sequence was found to be more selective and hybridized faster at room temperature than conventional 20-mer capture sequences. Particle sizes were evaluated from 100 nm to 1.5 µm in diameter, and the larger diameter particles produced greater detection signals. A better performance was obtained by employing magnetic microparticles and magnetically separating magnetic microparticle–RNA complexes from nonspecific materials, such as lysed cell constituents and cell debris, that can interfere with sandwich formation and detection. The high-density magnetic microparticles rested on the electrode surface, causing a portion of the oligonucleotides to adsorb to the working electrode surface. Full article
(This article belongs to the Proceedings of The 3rd International Electronic Conference on Biosensors)
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7 pages, 1823 KiB  
Proceeding Paper
Gold Nanostructure Orchestrated Electrochemical Immunosensor Integrated with Antibody-Electroactive Probe Conjugate for Rapid Detection of SARS-CoV-2 Antibody
Eng. Proc. 2023, 35(1), 29; https://doi.org/10.3390/IECB2023-14717 - 12 Jun 2023
Viewed by 553
Abstract
Viral detection has been studied predominantly in the last few years, along with the morbidity of COVID-19. Biosensors have been widely used for the detection of various biological molecules, showing a high potential for miniaturization and a friendly approach towards detection. Nanomaterials play [...] Read more.
Viral detection has been studied predominantly in the last few years, along with the morbidity of COVID-19. Biosensors have been widely used for the detection of various biological molecules, showing a high potential for miniaturization and a friendly approach towards detection. Nanomaterials play a significant role in the development of biosensing devices due to their distinct morphological, optical, electrical, chemical, and physical properties, which improve their sensing efficiency. Therefore, the present work reports the fabrication of an electrochemical immunosensor adorned with gold nanoparticles coupled to a redox indicator-labeled antibody conjugate for the rapid detection of SARS-CoV-2 antibodies. The fabricated immunosensor can detect SARS-CoV-2 antibodies within a linear detection range of 10–100 ngmL−1 and offer a sensitivity of 0.013 × 10−3 mA ng−1mLmm−2. The adopted concept can be extended further for the detection of other viral antibodies with high sensitivity and display high prospects for miniaturization, hence offering tremendous commercialization potential. Full article
(This article belongs to the Proceedings of The 3rd International Electronic Conference on Biosensors)
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7 pages, 3104 KiB  
Proceeding Paper
Molecularly Imprinted Polymers/Metal–Organic Framework (MIL-53) for Fluorescent Sensing of Ciprofloxacin in Water
Eng. Proc. 2023, 35(1), 30; https://doi.org/10.3390/IECB2023-14598 - 12 May 2023
Viewed by 649
Abstract
The contamination of water and food with antibiotics residues poses a severe risk to human health and aquatic environments. The excessive and uncontrolled use of antibiotics is one of the major causes of their presence in the environment. Their continuous consumption willingly or [...] Read more.
The contamination of water and food with antibiotics residues poses a severe risk to human health and aquatic environments. The excessive and uncontrolled use of antibiotics is one of the major causes of their presence in the environment. Their continuous consumption willingly or un-willingly can result in severe health issues such as allergy, headache, hypertension, muscle pain, and hormonal dysfunction. Beside these, the development of antimicrobial resistance (AMR) can make the situation more critical. Therefore, advanced analytical approaches over conventional techniques are required to detect antibiotic residues in a facile and cost-effective manner. The present work deals with the design of fluorescent nanostructures as sensing probes for the detection of ciprofloxacin. Here, we have synthesized NH2-MIL-53(Al) using a hydrothermal approach. This fluorescent metal–organic framework (MOF) was further combined with molecular imprinted polymers (MIPs) for the selective and specific detection of ciprofloxacin in aqueous solutions. The use of MIPs over other biomolecules (such as antibody, enzymes, and others) is highly promising as it avoids any kind of pre-treatment of the sample. The MIP@NH2-MIL-53(Al) nanostructure formation is confirmed by performing different characterization techniques involving both spectroscopy and microscopy. The performance of the developed fluorescent composite promotes its applicability for the highly sensitive and specific detection of ciprofloxacin in practical applications. Full article
(This article belongs to the Proceedings of The 3rd International Electronic Conference on Biosensors)
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1963 KiB  
Proceeding Paper
Chemical Transformation of Typical Biological Recognition Elements in Reactions with Nanosized Targets: A Study of Glutathione Coated Silver Nanoparticles
Eng. Proc. 2023, 35(1), 31; https://doi.org/10.3390/IECB2023-14571 - 08 May 2023
Viewed by 381
Abstract
Glutathione (GT) is a complexing agent that plays a key role in the functioning of a living cell. Gold nanoparticles are often used as transducers of nanosized biosensors, since they have the optical and chemical properties necessary for sensory applications, and make it [...] Read more.
Glutathione (GT) is a complexing agent that plays a key role in the functioning of a living cell. Gold nanoparticles are often used as transducers of nanosized biosensors, since they have the optical and chemical properties necessary for sensory applications, and make it possible to form a sensitive layer with the desired recognition element. Silver nanoparticles (AgNPs) also have attracted increasing interest to sensor applications due to the narrower plasmon resonance band compared to gold nanoparticles, but different surface chemistry. The purpose of this study is to provide an information about GT-coated AgNPs evolution as a system consisting of AgNPs transducer and GT recognition element. AgNPs are transformed through Ag+ to amorphous Ag, while GT promotes AgNPs to be dissolved, and gets decomposed by reactive oxygen species (ROS) during the transformation. Full article
(This article belongs to the Proceedings of The 3rd International Electronic Conference on Biosensors)
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9 pages, 1193 KiB  
Proceeding Paper
Effect of Intense Hot-Spot-Specific Local Fields on Fluorescein Adsorbed at 3D Porous Gold Architecture: Evolution of SERS Amplification and Photobleaching under Resonant Illumination
Eng. Proc. 2023, 35(1), 32; https://doi.org/10.3390/IECB2023-14606 - 16 May 2023
Cited by 2 | Viewed by 408
Abstract
Plasmonic nanostructures with a high density of confined areas with high local electromagnetic fields (hot spots) are sine qua nonto increase the efficiency of surface-enhanced Raman spectroscopy (SERS). These nanostructures can be used both to identify biological molecules and to monitor photochemical reactions [...] Read more.
Plasmonic nanostructures with a high density of confined areas with high local electromagnetic fields (hot spots) are sine qua nonto increase the efficiency of surface-enhanced Raman spectroscopy (SERS). These nanostructures can be used both to identify biological molecules and to monitor photochemical reactions occurring on the metal surface. In this work, using the method of pulsed laser deposition, three-dimensional (3D) porous wedge-shaped arrays of gold nanoparticles (Au NPs) were obtained with structural parameters varying along the substrate, such as film thickness, porosity, nanoparticles size, and the distance between them. The resulting arrays were structures with a regularly changing density of hot spots along the substrate, in which the enhancement of the electromagnetic field strength is due to the geometric parameters of the nanostructure.By analyzing the evolution of fluorescence and Raman scattering of fluorescein molecules adsorbed on the surface of porous gold under illumination at 532 nm, the processes in the region of extreme values of the electromagnetic field of surface nanostructures was studied. A correlation has been established between the amplification of optical signals and the structural features of the surface. A correlation between SERS and fluorescence signals indicates the predominant contribution of hot spots to the electromagnetic amplification of optical signals. The observed time evolution of the fluorescence and SERS intensity of fluorescein can be explained by the combination of molecular photodegradation, the reconstruction of the hot spot architecture due to local heating, and potent relocation of analyte molecules outside the area of measurement owing to the effects of thermal gradients. Full article
(This article belongs to the Proceedings of The 3rd International Electronic Conference on Biosensors)
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3557 KiB  
Proceeding Paper
Smartphone-Adapted Multianalyte Biosensor Platform for Fluorescent Analysis of Human Biomarkers and Immunosuppressive Drugs Using PQQ- and NAD+-Dependent Enzymes
Eng. Proc. 2023, 35(1), 33; https://doi.org/10.3390/IECB2023-14576 - 08 May 2023
Viewed by 461
Abstract
Here, we describe a multianalyte biosensor platform for the fluorescent analysis of different human state biomarkers (α-amylase, phenylalanine, glucose, lactate/pyruvate, alcohol) and some immunosuppressive drugs (cyclosporine A, tacrolimus, methotrexate, rapamycin) using chimeric PQQ- and natural NAD+-dependent enzymes. The principle of the [...] Read more.
Here, we describe a multianalyte biosensor platform for the fluorescent analysis of different human state biomarkers (α-amylase, phenylalanine, glucose, lactate/pyruvate, alcohol) and some immunosuppressive drugs (cyclosporine A, tacrolimus, methotrexate, rapamycin) using chimeric PQQ- and natural NAD+-dependent enzymes. The principle of the approach is based on the analysis of the brightness of photography of a sensor plate taken with a smartphone camera and processed using ImageJ software. The brightness of the image correlates with the fluorescence intensity of the sensor’s spots which is produced by the enzymatic reduction of phenazine methosulfate or its derivative used as a fluorescence probe at UV 356 nm irradiation, where the amount of the reduced dye depends on the concentration of the target analyte (the enzymatic substrate) in the tested sample. The sensor plate is composed of simple and cheap components, and the procedure of its preparation and usage is easy and does not require any specific skills or expensive instrumentation. The proposed sensor platform is characterized by a high selectivity and storage stability depending on the selectivity and stability characteristics of the used enzyme in an immobilized state. The proposed sensor platform could be used for precision quantitative analysis of a single (or several) analytes or used for a simultaneous qualitative multianalyte assay of them using Boolean logic gates. Full article
(This article belongs to the Proceedings of The 3rd International Electronic Conference on Biosensors)
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19736 KiB  
Proceeding Paper
Characterization of Spinal Cord Stimulation Electrode for Chronic Implant in Animal Models
Eng. Proc. 2023, 35(1), 34; https://doi.org/10.3390/IECB2023-14579 - 08 May 2023
Viewed by 487
Abstract
Spinal cord electrical (SCS) stimulation alleviates motor deficits in rodent and primate models of Parkinson’s disease due to a suppression of synchronous corticostriatal low-frequency oscillation. Limited epidural space requires resistant biocompatible microelectrodes to deliver efficiently electrical currents through a metal–cellular interface. Platinum (Pt) [...] Read more.
Spinal cord electrical (SCS) stimulation alleviates motor deficits in rodent and primate models of Parkinson’s disease due to a suppression of synchronous corticostriatal low-frequency oscillation. Limited epidural space requires resistant biocompatible microelectrodes to deliver efficiently electrical currents through a metal–cellular interface. Platinum (Pt) microelectrodes may lead to material degradation and topography modification under prolonged electrical stimulation. Thus, microstimulation performance over time can deteriorate and affect the functional recovery produced by SCS. To investigate electrodes commonly implanted in the epidural space of rats, Pt microelectrodes immersed in physiological saline underwent 48 h of electrical stimulation (100 Hz; 1.0, 1.3, and 1.6 mA). A wettability test was performed to characterize the interaction of the contact angle before and after stimulation, and it was found that there was an increase in this angle after the stimulation. An electrical impedance test showed that electrochemical interactions caused an increase in impedance after the stimulation. A roughness analysis also showed an increase in roughness after stimulation. Pt electrodes under chronic electric stimulation are susceptible to degradation, and further studies can improve electrode stability and efficacy as new sensor technologies become available. Full article
(This article belongs to the Proceedings of The 3rd International Electronic Conference on Biosensors)
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6 pages, 4505 KiB  
Proceeding Paper
Comparative Analysis of the Interaction of Cytochrome C with Supported Lipid Films and DNA Aptamers Using QCM-D Method
Eng. Proc. 2023, 35(1), 35; https://doi.org/10.3390/IECB2023-14752 - 12 Jun 2023
Viewed by 428
Abstract
Cytochrome c (cyt c) is an important indicator of cell apoptosis and can, therefore, be used for the diagnosis of cancer. We performed a comparative analysis of cyt c detection on the surface of lipid films or a monolayer of 11-mercaptoundecanoic acid (MUA) [...] Read more.
Cytochrome c (cyt c) is an important indicator of cell apoptosis and can, therefore, be used for the diagnosis of cancer. We performed a comparative analysis of cyt c detection on the surface of lipid films or a monolayer of 11-mercaptoundecanoic acid (MUA) with immobilized specific or nonspecific DNA aptamers. A quartz crystal microbalance with dissipation monitoring (QCM-D) in a multiharmonic mode was used to study the interaction of cyt c with various surfaces. For this purpose, changes in the resonant frequency, Δf, and dissipation, ΔD, were determined. The strongest interaction of cyt c was observed with sensors based on specific DNA aptamers that were accompanied by a decrease in frequency and an increase in dissipation. The limit of detection (LOD) for this aptasensor was established as 2.89 ± 0.12 nM. The interaction of cyt c with supported lipid films also resulted in a decrease in resonant frequency, but significant changes occurred only in the µM concentration range of cyt c. Changes in dissipation were much lower in comparison with aptamer-based surfaces, which suggests a weaker contribution of cyt c adsorption to the viscosity. Full article
(This article belongs to the Proceedings of The 3rd International Electronic Conference on Biosensors)
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6 pages, 1533 KiB  
Proceeding Paper
Combination of On-Chip Electromembrane Extraction with Solid-Phase Microextraction Using a Monolithic Nanocomposite as the Sorbent
Eng. Proc. 2023, 35(1), 36; https://doi.org/10.3390/IECB2023-14705 - 18 May 2023
Viewed by 624
Abstract
During the last few decades, many studies have focused on the development of environmentally friendly, efficient, and miniaturized sample preparation methods. In this study, solid-phase microextraction and electromembrane extraction methods were integrated to take advantage of both methods and achieve higher extraction recoveries [...] Read more.
During the last few decades, many studies have focused on the development of environmentally friendly, efficient, and miniaturized sample preparation methods. In this study, solid-phase microextraction and electromembrane extraction methods were integrated to take advantage of both methods and achieve higher extraction recoveries and clean-up. In this regard, Cu/Cr layered double hydroxide was dispersed in a poly(methacrylic acid-co-ethylene glycol dimethacrylate) polymerization mixture, and in situ polymerization was performed in the acceptor phase channel. Thereafter, EME-SPME on a chip was developed to extract non-steroidal anti-inflammatory drugs. The obtained limits of detection were 0.1–0.25 ng mL−1. Under evaluation of this method, extraction recoveries were obtained in the range of 83.34–90.87%, which corresponded to preconcentration factors of 56–61. The method was applied for the extraction of the drugs from real samples such as breast milk, urine, and plasma, and satisfactory results were obtained. Full article
(This article belongs to the Proceedings of The 3rd International Electronic Conference on Biosensors)
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2709 KiB  
Proceeding Paper
MD Average of Vibrational Spectra of Nucleotides in a SERS Sensor Simulation with Varying Number of Au Nanoparticles
Eng. Proc. 2023, 35(1), 37; https://doi.org/10.3390/IECB2023-14568 - 08 May 2023
Viewed by 580
Abstract
Applying the surface-enhanced Raman scattering (SERS) method to detect bioactive molecules such as DNA, proteins, and drugs has significant potential for structure-sensitive nondestructive chemical analysis. The SERS discrimination of single-molecule oligomers in DNA, microRNA, and proteins has attracted wide attention due to the [...] Read more.
Applying the surface-enhanced Raman scattering (SERS) method to detect bioactive molecules such as DNA, proteins, and drugs has significant potential for structure-sensitive nondestructive chemical analysis. The SERS discrimination of single-molecule oligomers in DNA, microRNA, and proteins has attracted wide attention due to the possibility of developing new sensing technology. The collected signal’s sensitivity has the level of detection of single oligomers, which can be compared with the simulation results corresponding to the sensor structure. We investigate the averaging method of the individual bond spectra for DNA nucleotides in the ring part of the pyrimidine (6-ring) and purine (6–5-ring) bases to form vibrational spectra obtained by molecular dynamics (MD) simulation. The system consists of the Au nanoparticles (from 1 to 4 NP assay) attached to a graphene sheet at the edge of the nanopore that localizes in the nanopore nucleotide interaction and spectral enhancement. The nucleotide translocation velocity set at 0.025 m/s compares with the experimental range. The vibrational spectra ring average has been tested for adenine and guanine with close correspondence (in the 500–1700 cm−1 range) to the experimental Raman and SERS spectra and extended to cytosine and thymine nucleotides. We also modified the number of the Au nanoparticles from one NP to four identical NPs to evaluate the influence of the interaction on the MD transient spectra. The variations of mode frequencies and amplitudes due to the number of Au NPs in bond spectra, as well as ring averages, mark the corresponding Au–nucleotide interactions and are considered for use as training sets for machine learning methods. Full article
(This article belongs to the Proceedings of The 3rd International Electronic Conference on Biosensors)
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5 pages, 1517 KiB  
Proceeding Paper
Developing a Sensitive Method for the Electrochemical Determination of Tetracycline Using MB-Tagged Aptamers on Gold Electrode Substrates
Eng. Proc. 2023, 35(1), 38; https://doi.org/10.3390/IECB2023-14597 - 12 May 2023
Viewed by 317
Abstract
An electrochemical aptasensor for the detection of tetracycline (TET) is prepared based on a methylene blue (MB)-tagged DNA aptamer, with the sequence 5′-MB-CCC CCG GCA GGC CAC GGC TTG GGTTGG TCC CAC TGC GCG-thiol-3′. The DNA aptamer is chemisorbed on a gold electrode [...] Read more.
An electrochemical aptasensor for the detection of tetracycline (TET) is prepared based on a methylene blue (MB)-tagged DNA aptamer, with the sequence 5′-MB-CCC CCG GCA GGC CAC GGC TTG GGTTGG TCC CAC TGC GCG-thiol-3′. The DNA aptamer is chemisorbed on a gold electrode and differential pulse voltammetry (DPV) is utilized for the detection. In particular, upon binding of the TET with the purpose-designed aptamer, there is an increase in the current intensity, as a result of the increased proximity of the MB molecule to the gold surface. The sensor is tested using aqueous samples spiked with TET concentrations between 1 and 1000 nM and a limit of detection (LOD) of 1.2 nM is determined. Furthermore, the dissociation constant is estimated to be 1.4 nM using a Lineweaver–Burk plot. Full article
(This article belongs to the Proceedings of The 3rd International Electronic Conference on Biosensors)
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Proceeding Paper
In-Silico Evaluation of the Folding and Structural Stability of Aptamers for Application in the Design of a Biosensor for Testosterone Detection
Eng. Proc. 2023, 35(1), 39; https://doi.org/10.3390/IECB2023-14739 - 31 May 2023
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Abstract
Currently, dietary supplements contain a wide range of non-specific concentrations of testosterone and/or its synthetic analogs, substances that are not permitted and that pose a risk to public health, which puts into perspective the need to evaluate and regulate the composition of these [...] Read more.
Currently, dietary supplements contain a wide range of non-specific concentrations of testosterone and/or its synthetic analogs, substances that are not permitted and that pose a risk to public health, which puts into perspective the need to evaluate and regulate the composition of these products. The present project proposes a control tool based on the development of a biosensor using aptamers as bio-recognition elements. The aptamer is a specific sequence of oligonucleotides with can fold into unique three-dimensional structures that interact with the analyte (testosterone and analogs). Integrally, it is proposed that the aptamers are coupled with gold nanoparticles functioning as a census and signal transduction system conducing to a biosensor with high sensitivity and selectivity and rapid response. In this work, modeling and molecular docking tools were used to evaluate the folding and structural stability of the aptamers. It is essential to carry out complete in silico analysis for the bio-recognition system and to evaluate the stability of the proposed aptamers with variations in the medium, allowing one to determine the conditions and adaptations necessary for the experimental analysis, design, and operation of the biosensor. On the other hand, evaluating the affinity and identifying the types of interactions between the aptamer and analyte allows us to locate the best candidate for the proposed aptamers. The stability of a set of nine sequences with proven interaction with testosterone was evaluated under different conditions, specifically, folding temperature (8.0 °C, 20 °C, and 30 °C), [Na+] (1.0 mm M, 50 mM, and 150 mM) and [Mg2+] (1.0 mm M, 2.0 mM, 3.0 mM, and 4.0 mM), with the MFold web server, RNA Composer, and PyMOL. The affinity and molecular interaction assays were carried out between each of the aptamers and three analytes: testosterone, testosterone undecanoate, and androstenedione using Auto dock Vina, Chimera, PyMOL, and Discovery Studio. The results showing stability and conformational changes in the aptamers allow us to conclude that the aptamers (T6, T5.1, and TESS1) are compatible with the conditions used in run tests and have high affinity for testosterone, the interactions of which are mainly established through non-covalent and hydrogen bonds. Full article
(This article belongs to the Proceedings of The 3rd International Electronic Conference on Biosensors)
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