Research

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16 pages, 3662 KiB

Open AccessArticle

Time-Resolved Fluorescence Spectroscopy of Molecularly Imprinted Nanoprobes as an Ultralow Detection Nanosensing Tool for Protein Contaminants

by Alessandra Maria Bossi, Alice Marinangeli, Alberto Quaranta, Lucio Pancheri and Devid Maniglio

Biosensors 2023, 13(7), 745; https://doi.org/10.3390/bios13070745 - 19 Jul 2023

Viewed by 1334

Abstract

Currently, optical sensors based on molecularly imprinted polymers (MIPs) have been attracting significant interest. MIP sensing relies on the combination of the MIP’s selective capability, which is conveyed to the polymeric material by a template-assisted synthesis, with optical techniques that offer exquisite sensitivity. [...] Read more.

Currently, optical sensors based on molecularly imprinted polymers (MIPs) have been attracting significant interest. MIP sensing relies on the combination of the MIP’s selective capability, which is conveyed to the polymeric material by a template-assisted synthesis, with optical techniques that offer exquisite sensitivity. In this work, we devised an MIP nanoparticle optical sensor for the ultralow detection of serum albumin through time-resolved fluorescence spectroscopy. The Fluo-nanoMIPs (∅~120 nm) were synthetized using fluorescein-O-methacrylate (0.1×, 1×, 10× mol:mol versus template) as an organic fluorescent reporter. The ability of 0.1× and 1×Fluo-nanoMIPs to bind albumin (15 fM–150 nM) was confirmed by fluorescence intensity analyses and isothermal titration calorimetry. The apparent dissociation constant (K_app) was 30 pM. Conversely, the 10× fluorophore content did not enable monitoring binding. Then, the time-resolved fluorescence spectroscopy of the nanosensors was studied. The 1×Fluo-nanoMIPs showed a decrease in fluorescence lifetime upon binding to albumin (100 fM–150 nM), K_app = 28 pM, linear dynamic range 3.0–83.5 pM, limit of detection (LOD) 1.26 pM. Selectivity was confirmed testing 1×Fluo-nanoMIPs against competitor proteins. Finally, as a proof of concept, the nanosensors demonstrated detection of the albumin (1.5 nM) spiked in wine samples, suggesting a possible scaling up of the method in monitoring allergens in wines. Full article

(This article belongs to the Special Issue Chemical and Biochemical Sensors/Nanosensors for Medical, Environmental and Security Applications)

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12 pages, 1501 KiB

Open AccessArticle

Rapid and Simple Buffer Exchange Using Cation-Exchange Chromatography to Improve Point-of-Care Detection of Pharmacological Agents

by Michael C. Brothers, Maegan Kornexl, Barlow Guess, Yuri Kim, Darrin Ott, Jennifer A. Martin, Dara Regn and Steve S. Kim

Biosensors 2023, 13(6), 635; https://doi.org/10.3390/bios13060635 - 08 Jun 2023

Viewed by 1675

Abstract

The current COVID-19 pandemic has highlighted the power, speed, and simplicity of point-of-care (POC) diagnostics. POC diagnostics are available for a wide range of targets, including both drugs of abuse as well as performance-enhancing drugs. For pharmacological monitoring, minimally invasive fluids such as [...] Read more.

The current COVID-19 pandemic has highlighted the power, speed, and simplicity of point-of-care (POC) diagnostics. POC diagnostics are available for a wide range of targets, including both drugs of abuse as well as performance-enhancing drugs. For pharmacological monitoring, minimally invasive fluids such as urine and saliva are commonly sampled. However, false positives or negatives caused by interfering agents excreted in these matrices may confound results. For example, false positives have, in most cases, prevented the use of POC diagnostics for pharmacological agent detection; the consequence is that centralized labs are instead tasked to perform these screenings, resulting in significant delays between sampling and testing. Thus, a rapid, simple, and inexpensive methodology for sample purification is required for the POC to reach a field-deployable tool for the pharmacological human health and performance assessments. Buffer exchange is a simple, rapid approach to remove interfering agents, but has traditionally been difficult to perform on small pharmacological molecules. Therefore, in this communication, we use salbutamol, a performance-enhancing drug, as a case example to demonstrate the efficacy of ion-exchange chromatography as a technique to perform buffer exchange for charged pharmacological agents. This manuscript demonstrates the efficacy of this technique leveraging a commercial spin column to remove interfering agents found in simulant urines, such as proteins, creatinine, and urea, while retaining salbutamol. The utility and efficacy of the method was then confirmed in actual saliva samples. The eluent was then collected and run on the lateral flow assays (LFAs), improving the reported limit of detection by over 5× (new lower limit of detection of 10 ppb compared to reported 60 ppb by the manufacturer) while simultaneously removing noise due to background interfering agents. Full article

(This article belongs to the Special Issue Chemical and Biochemical Sensors/Nanosensors for Medical, Environmental and Security Applications)

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20 pages, 5699 KiB

Open AccessArticle

Hybridization of Co₃S₄ and Graphitic Carbon Nitride Nanosheets for High-performance Nonenzymatic Sensing of H₂O₂

by Asha Ramesh, Ajay Ajith, Neeraja Sinha Gudipati, Siva Rama Krishna Vanjari, S. Abraham John, Vasudevanpillai Biju and Ch Subrahmanyam

Biosensors 2023, 13(1), 108; https://doi.org/10.3390/bios13010108 - 07 Jan 2023

Cited by 6 | Viewed by 2741

Abstract

The development of efficient H₂O₂ sensors is crucial because of their multiple functions inside and outside the biological system and the adverse effects that a higher concentration can cause. This work reports a highly sensitive and selective non-enzymatic electrochemical H [...] Read more.

The development of efficient H₂O₂ sensors is crucial because of their multiple functions inside and outside the biological system and the adverse effects that a higher concentration can cause. This work reports a highly sensitive and selective non-enzymatic electrochemical H₂O₂ sensor achieved through the hybridization of Co₃S₄ and graphitic carbon nitride nanosheets (GCNNS). The Co₃S₄ is synthesized via a hydrothermal method, and the bulk g-C₃N₄ (b-GCN) is prepared by the thermal polycondensation of melamine. The as-prepared b-GCN is exfoliated into nanosheets using solvent exfoliation, and the composite with Co₃S₄ is formed during nanosheet formation. Compared to the performances of pure components, the hybrid structure demonstrates excellent electroreduction towards H₂O₂. We investigate the H₂O₂-sensing performance of the composite by cyclic voltammetry, differential pulse voltammetry, and amperometry. As an amperometric sensor, the Co₃S₄/GCNNS exhibits high sensitivity over a broad linear range from 10 nM to 1.5 mM H₂O₂ with a high detection limit of 70 nM and fast response of 3 s. The excellent electrocatalytic properties of the composite strengthen its potential application as a sensor to monitor H₂O₂ in real samples. The remarkable enhancement of the electrocatalytic activity of the composite for H₂O₂ reduction is attributed to the synergistic effect between Co₃S₄ and GCNNS. Full article

(This article belongs to the Special Issue Chemical and Biochemical Sensors/Nanosensors for Medical, Environmental and Security Applications)

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22 pages, 7385 KiB

Open AccessArticle

Palladium Hydroxide (Pearlman’s Catalyst) Doped MXene (Ti₃C₂Tx) Composite Modified Electrode for Selective Detection of Nicotine in Human Sweat

by Vasanth Magesh, Ashok K. Sundramoorthy, Dhanraj Ganapathy, Raji Atchudan, Sandeep Arya, Razan A. Alshgari and Ahmed Muteb Aljuwayid

Biosensors 2023, 13(1), 54; https://doi.org/10.3390/bios13010054 - 29 Dec 2022

Cited by 17 | Viewed by 2662

Abstract

High concentrations of nicotine (40 to 60 mg) are more dangerous for adults who weigh about 70 kg. Herein, we developed an electrochemical transducer using an MXene (Ti₃C₂Tx)/palladium hydroxide-supported carbon (Pearlman’s catalyst) composite (MXene/Pd(OH)₂/C) for the identification [...] Read more.

High concentrations of nicotine (40 to 60 mg) are more dangerous for adults who weigh about 70 kg. Herein, we developed an electrochemical transducer using an MXene (Ti₃C₂Tx)/palladium hydroxide-supported carbon (Pearlman’s catalyst) composite (MXene/Pd(OH)₂/C) for the identification of nicotine levels in human sweat. Firstly, the MXene was doped with Pd(OH)₂/C (PHC) by mechanical grinding followed by an ultrasonication process to obtain the MXene/PHC composite. Secondly, XRD, Raman, FE-SEM, EDS and E-mapping analysis were utilized to confirm the successful formation of MXene/PHC composite. Using MXene/PHC composite dispersion, an MXene/PHC composite-modified glassy carbon electrode (MXene/PHC/GCE) was prepared, which showed high sensitivity as well as selectivity towards nicotine (300 µM NIC) oxidation in 0.1 M phosphate buffer (pH = 7.4) by cyclic voltammetry (CV) and amperometry. The MXene/PHC/GCE had reduced the over potential of nicotine oxidation (about 200 mV) and also enhanced the oxidation peak current (8.9 µA) compared to bare/GCE (2.1 µA) and MXene/GCE (5.5 µA). Moreover, the optimized experimental condition was used for the quantification of NIC from 0.25 µM to 37.5 µM. The limit of detection (LOD) and sensitivity were 27 nM and 0.286 µA µM⁻¹ cm², respectively. The MXene/PHC/GCE was also tested in the presence of Na⁺, Mg²⁺, Ca²⁺, hydrogen peroxide, acetic acid, ascorbic acid, dopamine and glucose. These molecules were not interfered during NIC analysis, which indicated the good selectivity of the MXene/PHC/GCE sensor. In addition, electrochemical determination of NIC was successfully carried out in the human sweat samples collected from a tobacco smoker. The recovery percentage of NIC in the sweat sample was 97%. Finally, we concluded that the MXene/PHC composite-based sensor can be prepared for the accurate determination of NIC with high sensitivity, selectivity and stability in human sweat samples. Full article

(This article belongs to the Special Issue Chemical and Biochemical Sensors/Nanosensors for Medical, Environmental and Security Applications)

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12 pages, 2572 KiB

Open AccessArticle

Ratiometric Fluorescence Immunoassay Based on Carbon Quantum Dots for Sensitive Detection of Malachite Green in Fish

by Guangxin Yang, Jingru Zhang, Lin Gu, Yunyu Tang, Xuan Zhang, Xuanyun Huang, Xiaosheng Shen, Wenlei Zhai, Essy Kouadio Fodjo and Cong Kong

Biosensors 2023, 13(1), 38; https://doi.org/10.3390/bios13010038 - 27 Dec 2022

Cited by 5 | Viewed by 1693

Abstract

Malachite green (MG) is a synthetic poisonous organic compound that has been banned in many countries as a veterinary drug for aquaculture. An efficient, fast and sensitive method is urgently needed for monitoring the illegal use of malachite green (MG) in aquaculture. In [...] Read more.

Malachite green (MG) is a synthetic poisonous organic compound that has been banned in many countries as a veterinary drug for aquaculture. An efficient, fast and sensitive method is urgently needed for monitoring the illegal use of malachite green (MG) in aquaculture. In this study, a novel ratiometric fluorescence immunoassay was established. Nitrogen-doped carbon quantum dots were used as ratiometric fluorescent probes with a fluorescence peak at 450 nm. Horseradish peroxidase was employed to convert o-phenylenediamine to 2,3-diaminophenazine, with a new fluorescence peak at 580 nm and a strong absorption at 420 nm. The inner filter effect between N-CQD fluorescence and DAP absorption was identified. It allows for the ratiometric detection of MG using a fluorescent immunoassay. The results demonstrated a linear ratiometric fluorescence response for MG between 0.1 and 12.8 ng·mL⁻¹. The limit of detection of this method was verified to be 0.097 μg·kg⁻¹ with recoveries ranging from 81.88 to 108%, and the relative standard deviations were below 3%. Furthermore, this method exhibited acceptable consistency with the LC-MS/MS results when applied for MG screening in real samples. These results demonstrated a promising application of this novel ratiometric fluorescence immunoassay for MG screening with the merits of rapid detection, simple sample preparation, and stable signal readout. It can be an alternative to other traditional methods if there are difficulties in the availability of expensive instruments, and achieve comparable results or even more sensitivity than other reported methods. Full article

(This article belongs to the Special Issue Chemical and Biochemical Sensors/Nanosensors for Medical, Environmental and Security Applications)

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16 pages, 8209 KiB

Open AccessArticle

Label-Free Myoglobin Biosensor Based on Pure and Copper-Doped Titanium Dioxide Nanomaterials

by Ahmad Umar, Mazharul Haque, Shafeeque G. Ansari, Hyung-Kee Seo, Ahmed A. Ibrahim, Mohsen A. M. Alhamami, Hassan Algadi and Zubaida A. Ansari

Biosensors 2022, 12(12), 1151; https://doi.org/10.3390/bios12121151 - 08 Dec 2022

Cited by 5 | Viewed by 1488

Abstract

In this study, using pure and copper-doped titanium dioxide (Cu-TiO₂) nanostructures as the base matrix, enzyme-less label free myoglobin detection to identify acute myocardial infarction was performed and presented. The Cu-TiO₂ nanomaterials were prepared using facile sol–gel method. In order [...] Read more.

In this study, using pure and copper-doped titanium dioxide (Cu-TiO₂) nanostructures as the base matrix, enzyme-less label free myoglobin detection to identify acute myocardial infarction was performed and presented. The Cu-TiO₂ nanomaterials were prepared using facile sol–gel method. In order to comprehend the morphologies, compositions, structural, optical, and electrochemical characteristics, the pure and Cu-TiO₂ nanomaterials were investigated by several techniques which clearly revealed good crystallinity and high purity. To fabricate the enzyme-less label free biosensor, thick films of synthesized nanomaterials were applied to the surface of a pre-fabricated gold screen-printed electrode (Au-SPE), which serves as a working electrode to construct the myoglobin (Mb) biosensors. The interference study of the fabricated biosensor was also carried out with human serum albumin (HSA) and cytochrome c (cyt-c). Interestingly, the Cu-doped TiO₂ nanomaterial-based Mb biosensor displayed a higher sensitivity of 61.51 µAcm⁻²/nM and a lower detection limit of 14 pM with a response time of less than 10 ms. Full article

(This article belongs to the Special Issue Chemical and Biochemical Sensors/Nanosensors for Medical, Environmental and Security Applications)

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15 pages, 4850 KiB

Open AccessArticle

An Immunocolorimetric Sensing System for Highly Sensitive and High-Throughput Detection of BNP with Carbon-Gold Nanocomposites Amplification

by Xin Liu, Ying Gan, Fengheng Li, Yong Qiu, Yuxiang Pan, Hao Wan and Ping Wang

Biosensors 2022, 12(8), 619; https://doi.org/10.3390/bios12080619 - 09 Aug 2022

Cited by 3 | Viewed by 1700

Abstract

Conventional immunocolorimetric sensing of biomolecules continues to be challenged with low sensitivity although its wide application as a diagnostic tool in medicine and biotechnology. Herein, we present a multifunctional immunocolorimetric sensing system for sensitive and high-throughput detection of B-type natriuretic peptide (BNP) with [...] Read more.

Conventional immunocolorimetric sensing of biomolecules continues to be challenged with low sensitivity although its wide application as a diagnostic tool in medicine and biotechnology. Herein, we present a multifunctional immunocolorimetric sensing system for sensitive and high-throughput detection of B-type natriuretic peptide (BNP) with carbon-gold nanocomposite (CGNs) amplification. Using a “green” strategy, monodisperse carbon nanospheres (CNs) were successfully synthesized by glucose carbonization. A simple and efficient hydrothermal method was developed to assemble abundant gold nanoparticles (AuNPs) onto the surfaces of CNs. The resulting CGNs were characterized and utilized for biomarker detection with superior properties of easy manufacturing, good biocompatibility, satisfactory chemical stability, and high loading capacity for biomolecules. As a proof of concept, the as-prepared CGNs were conjugated with horseradish peroxidase-labeled antibody against BNP (CGNs@AntiBNP-HRP) functioning as the carrier, signal amplifier, and detector for the sensitive detection of BNP. Under optimal conditions, the established CGNs@AntiBNP-HRP immunoprobe remarkably enhanced the detection performance of BNP, achieving signal amplification of more than 9 times compared to the conventional method. Based on our self-developed bionic electronic eye (e-Eye) and CGNs@AntiBNP-HRP immunoprobe, the multifunctional sensing system displayed a wide dynamic linear range of 3.9–500 ng/mL and a LOD of 0.640 ng/mL for BNP detection with high specificity, good accuracy and reproducibility. This portable sensing system with enhanced performance demonstrates great potential for BNP detection in point of care applications, and offers a universal and reliable platform for in vitro biomarker detection. Full article

(This article belongs to the Special Issue Chemical and Biochemical Sensors/Nanosensors for Medical, Environmental and Security Applications)

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Review

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22 pages, 18035 KiB

Open AccessReview

Current Innovations in Intraocular Pressure Monitoring Biosensors for Diagnosis and Treatment of Glaucoma—Novel Strategies and Future Perspectives

by Rubiya Raveendran, Lokesh Prabakaran, Rethinam Senthil, Beryl Vedha Yesudhason, Sankari Dharmalingam, Weslen Vedakumari Sathyaraj and Raji Atchudan

Biosensors 2023, 13(6), 663; https://doi.org/10.3390/bios13060663 - 18 Jun 2023

Cited by 3 | Viewed by 3151

Abstract

Biosensors are devices that quantify biologically significant information required for diverse applications, such as disease diagnosis, food safety, drug discovery and detection of environmental pollutants. Recent advancements in microfluidics, nanotechnology and electronics have led to the development of novel implantable and wearable biosensors [...] Read more.

Biosensors are devices that quantify biologically significant information required for diverse applications, such as disease diagnosis, food safety, drug discovery and detection of environmental pollutants. Recent advancements in microfluidics, nanotechnology and electronics have led to the development of novel implantable and wearable biosensors for the expedient monitoring of diseases such as diabetes, glaucoma and cancer. Glaucoma is an ocular disease which ranks as the second leading cause for loss of vision. It is characterized by the increase in intraocular pressure (IOP) in human eyes, which results in irreversible blindness. Currently, the reduction of IOP is the only treatment used to manage glaucoma. However, the success rate of medicines used to treat glaucoma is quite minimal due to their curbed bioavailability and reduced therapeutic efficacy. The drugs must pass through various barriers to reach the intraocular space, which in turn serves as a major challenge in glaucoma treatment. Rapid progress has been observed in nano-drug delivery systems for the early diagnosis and prompt therapy of ocular diseases. This review gives a deep insight into the current advancements in the field of nanotechnology for detecting and treating glaucoma, as well as for the continuous monitoring of IOP. Various nanotechnology-based achievements, such as nanoparticle/nanofiber-based contact lenses and biosensors that can efficiently monitor IOP for the efficient detection of glaucoma, are also discussed. Full article

(This article belongs to the Special Issue Chemical and Biochemical Sensors/Nanosensors for Medical, Environmental and Security Applications)

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