2023

Jump to: 2022, 2021

17 pages, 3415 KiB

Open AccessArticle

Small-Molecule Analysis Based on DNA Strand Displacement Using a Bacteriorhodopsin Photoelectric Transducer: Taking ATP as an Example

by Hsiu-Mei Chen, Wen-Chang Wang and Hong-Ren Chen

Sensors 2023, 23(17), 7453; https://doi.org/10.3390/s23177453 - 27 Aug 2023

Cited by 1 | Viewed by 865

Abstract

A uniformly oriented purple membrane (PM) monolayer containing photoactive bacteriorhodopsin has recently been applied as a sensitive photoelectric transducer to assay color proteins and microbes quantitatively. This study extends its application to detecting small molecules, using adenosine triphosphate (ATP) as an example. A [...] Read more.

A uniformly oriented purple membrane (PM) monolayer containing photoactive bacteriorhodopsin has recently been applied as a sensitive photoelectric transducer to assay color proteins and microbes quantitatively. This study extends its application to detecting small molecules, using adenosine triphosphate (ATP) as an example. A reverse detection method is used, which employs AuNPs labeling and specific DNA strand displacement. A PM monolayer-coated electrode is first covalently conjugated with an ATP-specific nucleic acid aptamer and then hybridized with another gold nanoparticle-labeled nucleic acid strand with a sequence that is partially complementary to the ATP aptamer, in order to significantly minimize the photocurrent that is generated by the PM. The resulting ATP-sensing chip restores its photocurrent production in the presence of ATP, and the photocurrent recovers more effectively as the ATP concentration increases. Direct and single-step ATP detection is achieved in 15 min, with detection limits of 5 nM and a dynamic range of 5 nM–0.1 mM. The sensing chip exhibits high selectivity against other ATP analogs and is satisfactorily stable in storage. The ATP-sensing chip is used to assay bacterial populations and achieves a detection limit for Bacillus subtilis and Escherichia coli of 10² and 10³ CFU/mL, respectively. The demonstration shows that a variety of small molecules can be simultaneously quantified using PM-based biosensors. Full article

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28 pages, 3100 KiB

Open AccessPerspective

The Development of Optomechanical Sensors—Integrating Diffractive Optical Structures for Enhanced Sensitivity

by Faolan Radford McGovern, Aleksandra Hernik, Catherine Grogan, George Amarandei and Izabela Naydenova

Sensors 2023, 23(12), 5711; https://doi.org/10.3390/s23125711 - 19 Jun 2023

Cited by 1 | Viewed by 1260

Abstract

The term optomechanical sensors describes devices based on coupling the optical and mechanical sensing principles. The presence of a target analyte leads to a mechanical change, which, in turn, determines an alteration in the light propagation. Having higher sensitivity in comparison with the [...] Read more.

The term optomechanical sensors describes devices based on coupling the optical and mechanical sensing principles. The presence of a target analyte leads to a mechanical change, which, in turn, determines an alteration in the light propagation. Having higher sensitivity in comparison with the individual technologies upon which they are based, the optomechanical devices are used in biosensing, humidity, temperature, and gases detection. This perspective focuses on a particular class, namely on devices based on diffractive optical structures (DOS). Many configurations have been developed, including cantilever- and MEMS-type devices, fiber Bragg grating sensors, and cavity optomechanical sensing devices. These state-of-the-art sensors operate on the principle of a mechanical transducer coupled with a diffractive element resulting in a variation in the intensity or wavelength of the diffracted light in the presence of the target analyte. Therefore, as DOS can further enhance the sensitivity and selectivity, we present the individual mechanical and optical transducing methods and demonstrate how the DOS introduction can lead to an enhanced sensitivity and selectivity. Their (low-) cost manufacturing and their integration in new sensing platforms with great adaptability across many sensing areas are discussed, being foreseen that their implementation on wider application areas will further increase. Full article

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14 pages, 3492 KiB

Open AccessArticle

Electrochemical Detection of ompA Gene of C. sakazakii Based on Glucose-Oxidase-Mimicking Nanotags of Gold-Nanoparticles-Doped Copper Metal-organic Frameworks

by Hongyan Zhang, Guiqing Xu, Yuming Chen, Xu Li, Shaopeng Wang, Feihao Jiang, Pengyang Zhan, Chuanfu Lu, Xiaodong Cao, Yongkang Ye and Yunlai Tao

Sensors 2023, 23(9), 4396; https://doi.org/10.3390/s23094396 - 29 Apr 2023

Cited by 4 | Viewed by 1460

Abstract

The present work developed an electrochemical genosensor for the detection of virulence outer membrane protein A (ompA, tDNA) gene of Cronobacter sakazakii (C. sakazakii) by exploiting the excellent glucose-oxidase-mimicking activity of copper Metal-organic frameworks (Cu-MOF) doped with gold nanoparticle (AuNPs). [...] Read more.

The present work developed an electrochemical genosensor for the detection of virulence outer membrane protein A (ompA, tDNA) gene of Cronobacter sakazakii (C. sakazakii) by exploiting the excellent glucose-oxidase-mimicking activity of copper Metal-organic frameworks (Cu-MOF) doped with gold nanoparticle (AuNPs). The signal nanotags of signal probes (sDNA) that biofunctionalized AuNPs@Cu-MOF (sDNA-AuNPs@Cu-MOF) were designed using an Au-S bond. The biosensor was prepared by immobilization capture probes (cDNA) onto an electrodeposited AuNPs-modified glassy carbon electrode (GCE). AuNPs@Cu-MOF was introduced onto the surface of the GCE via a hybridization reaction between cDNA and tDNA, as well as tDNA and sDNA. Due to the enhanced oxidase-mimicking activity of AuNPs@Cu-MOF to glucose, the biosensor gave a linear range of 1.0 × 10⁻¹⁵ to 1.0 × 10⁻⁹ mol L⁻¹ to tDNA with a detection limit (LOD) of 0.42 fmol L⁻¹ under optimized conditions using differential pulse voltammetry measurement (DPV). It can be applied in the direct detection of ompA gene segments in total DNA extracts from C. sakazakii with a broad linear range of 5.4−5.4 × 10⁵ CFU mL⁻¹ and a LOD of 0.35 CFU mL⁻¹. The biosensor showed good selectivity, fabricating reproducibility and storage stability, and can be used for the detection of ompA gene segments in real samples with recovery between 87.5% and 107.3%. Full article

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14 pages, 2323 KiB

Open AccessArticle

Carbon Fiber Paper Sensor for Determination of Trimethoprim Antibiotic in Fish Samples

by Álvaro Torrinha, Miguel Tavares, Vitória Dibo, Cristina Delerue-Matos and Simone Morais

Sensors 2023, 23(7), 3560; https://doi.org/10.3390/s23073560 - 29 Mar 2023

Cited by 4 | Viewed by 1450

Abstract

The increase in anthropogenic pollution raises serious concerns regarding contamination of water bodies and aquatic species with potential implications on human health. Pharmaceutical compounds are a type of contaminants of emerging concern that are increasingly consumed and, thus, being frequently found in the [...] Read more.

The increase in anthropogenic pollution raises serious concerns regarding contamination of water bodies and aquatic species with potential implications on human health. Pharmaceutical compounds are a type of contaminants of emerging concern that are increasingly consumed and, thus, being frequently found in the aquatic environment. In this sense, an electrochemical sensor based on an unmodified and untreated carbon fiber paper (CPS—carbon paper sensor) was simply employed for the analysis of trimethoprim antibiotic in fish samples. First, the analytical conditions were thoroughly optimized in order for the CPS to achieve maximum performance in trimethoprim determination. Therefore, an electrolyte (0.1 M Britton–Robinson buffer) pH of 7 was selected and for square wave voltammetry parameters, optimum values of amplitude, frequency and step potential corresponded to 0.02 V, 50 Hz, and 0.015 V, respectively, whereas the deposition of analyte occurred at +0.7 V for 60 s. In these optimum conditions, the obtained liner range (0.05 to 2 µM), sensitivity (48.8 µA µM⁻¹ cm⁻²), and LOD (0.065 µM) competes favorably with the commonly used GCE-based sensors or BDD electrodes that employ nanostructuration or are more expensive. The CPS was then applied for trimethoprim determination in fish samples after employing a solid phase extraction procedure based on QuEChERS salts, resulting in recoveries of 105.9 ± 1.8% by the standard addition method. Full article

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16 pages, 27318 KiB

Open AccessArticle

Measurement of Water Vapor Condensation on Apple Surfaces during Controlled Atmosphere Storage

by Manfred Linke, Ulrike Praeger, Daniel A. Neuwald and Martin Geyer

Sensors 2023, 23(3), 1739; https://doi.org/10.3390/s23031739 - 03 Feb 2023

Cited by 4 | Viewed by 2061

Abstract

Apples are stored at temperatures close to 0 °C and high relative humidity (up to 95%) under controlled atmosphere conditions. Under these conditions, the cyclic operation of the refrigeration machine and the associated temperature fluctuations can lead to localized undershoots of the dew [...] Read more.

Apples are stored at temperatures close to 0 °C and high relative humidity (up to 95%) under controlled atmosphere conditions. Under these conditions, the cyclic operation of the refrigeration machine and the associated temperature fluctuations can lead to localized undershoots of the dew point on fruit surfaces. The primary question for the present study was to prove that such condensation processes can be measured under practical conditions during apple storage. Using the example of a measuring point in the upper apple layer of a large bin in the supply air area, this evidence was provided. Using two independent measuring methods, a wetness sensor attached to the apple surface and determination of climatic conditions near the fruit, the phases of condensation, namely active condensation and evaporation, were measured over three weeks as a function of the operating time of the cooling system components (refrigeration machine, fans, defrosting regime). The system for measurement and continuous data acquisition in the case of an airtight CA-storage room is presented and the influence of the operation of the cooling system components in relation to condensation phenomena was evaluated. Depending on the set point specifications for ventilation and defrost control, condensed water was present on the apple surface between 33.4% and 100% of the duration of the varying cooling/re-warming cycles. Full article

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2022

Jump to: 2023, 2021

9 pages, 1187 KiB

Open AccessArticle

Determination of Fumonisin B₁ by Aptamer-Based Fluorescence Resonance Energy Transfer

by Xinyue Zhao, Jiale Gao, Yuzhu Song, Jinyang Zhang and Qinqin Han

Sensors 2022, 22(22), 8598; https://doi.org/10.3390/s22228598 - 08 Nov 2022

Cited by 3 | Viewed by 1243

Abstract

Fumonisin FB is produced by Fusarium moniliforme Sheld, of which FB₁ is the most common and the most toxic. The establishment of a rapid detection method is an important means to prevent and control FB₁ pollution. A highly sensitive fluorescent sensor [...] Read more.

Fumonisin FB is produced by Fusarium moniliforme Sheld, of which FB₁ is the most common and the most toxic. The establishment of a rapid detection method is an important means to prevent and control FB₁ pollution. A highly sensitive fluorescent sensor based on an aptamer for the rapid detection of fumonisin B₁ (FB₁) in corn was established. In this study, 5-carboxyfluorescein (FAM) was labeled on the aptamer of FB₁ (F10). F10 was adsorbed on the surface of graphene oxide (GO) by π-π stacking. The FAM fluorescence signal could be quenched by fluorescence resonance energy transfer between fluorescent molecules and graphene oxide (GO). In the presence of FB₁, the binding efficiency of the aptamer to GO was reduced. Therefore, the content of FB₁ in corn samples was determined by fluorescence measurements of mixed FAM-labeled F10, GO and corn samples. This method had a good linear relationship in an FB₁ concentration range of 0–3000 ng/mL. The equation was y = 0.2576x + 10.98, R² = 0.9936. The limit of detection was 14.42 ng/mL, and the limit of quantification was 43.70 ng/mL. The recovery of a spiked standard in the corn sample was 89.13–102.08%, and the time of detection was 30 min. Full article

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14 pages, 2279 KiB

Open AccessArticle

Exploratory Research on Sweetness Perception: Decision Trees to Study Electroencephalographic Data and Its Relationship with the Explicit Response to Sweet Odor, Taste, and Flavor

by Elena Romeo-Arroyo, Javier Soria, María Mora, Francisco Laport, Aitor Moreno-Fernandez-de-Leceta and Laura Vázquez-Araújo

Sensors 2022, 22(18), 6787; https://doi.org/10.3390/s22186787 - 08 Sep 2022

Cited by 1 | Viewed by 1944

Abstract

Using implicit responses to determine consumers’ response to different stimuli is becoming a popular approach, but research is still needed to understand the outputs of the different technologies used to collect data. During the present research, electroencephalography (EEG) responses and self-reported liking and [...] Read more.

Using implicit responses to determine consumers’ response to different stimuli is becoming a popular approach, but research is still needed to understand the outputs of the different technologies used to collect data. During the present research, electroencephalography (EEG) responses and self-reported liking and emotions were collected on different stimuli (odor, taste, flavor samples) to better understand sweetness perception. Artificial intelligence analytics were used to classify the implicit responses, identifying decision trees to discriminate the stimuli by activated sensory system (odor/taste/flavor) and by nature of the stimuli (‘sweet’ vs. ‘non-sweet’ odors; ‘sweet-taste’, ‘sweet-flavor’, and ‘non-sweet flavor’; and ‘sweet stimuli’ vs. ‘non-sweet stimuli’). Significant differences were found among self-reported-liking of the stimuli and the emotions elicited by the stimuli, but no clear relationship was identified between explicit and implicit data. The present research sums interesting data for the EEG-linked research as well as for EEG data analysis, although much is still unknown about how to properly exploit implicit measurement technologies and their data. Full article

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17 pages, 5594 KiB

Open AccessArticle

Development and Automation of a Bacterial Biosensor to the Targeting of the Pollutants Toxic Effects by Portable Raman Spectrometer

by Oleksandra Bandeliuk, Ali Assaf, Marine Bittel, Marie-Jose Durand and Gérald Thouand

Sensors 2022, 22(12), 4352; https://doi.org/10.3390/s22124352 - 08 Jun 2022

Cited by 5 | Viewed by 1865

Abstract

Water quality monitoring requires a rapid and sensitive method that can detect multiple hazardous pollutants at trace levels. This study aims to develop a new generation of biosensors using a low-cost fiber-optic Raman device. An automatic measurement system was thus conceived, built and [...] Read more.

Water quality monitoring requires a rapid and sensitive method that can detect multiple hazardous pollutants at trace levels. This study aims to develop a new generation of biosensors using a low-cost fiber-optic Raman device. An automatic measurement system was thus conceived, built and successfully tested with toxic substances of three different types: antibiotics, heavy metals and herbicides. Raman spectroscopy provides a multiparametric view of metabolic responses of biological organisms to these toxic agents through their spectral fingerprints. Spectral analysis identified the most susceptible macromolecules in an E. coli model strain, providing a way to determine specific toxic effects in microorganisms. The automation of Raman analysis reduces the number of spectra required per sample and the measurement time: for four samples, time was cut from 3 h to 35 min by using a multi-well sample holder without intervention from an operator. The correct classifications were, respectively, 99%, 82% and 93% for the different concentrations of norfloxacin, while the results were 85%, 93% and 81% for copper and 92%, 90% and 96% for 3,5-dichlorophenol at the three tested concentrations. The work initiated here advances the technology needed to use Raman spectroscopy coupled with bioassays so that together, they can advance field toxicological testing. Full article

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2021

Jump to: 2023, 2022

13 pages, 2063 KiB

Open AccessArticle

Upconversion Nanoparticles-Based Fluorescence Immunoassay for the Sensitive Detection of 2-Amino-3-methylimidazo [4,5-f] Quinoline (IQ) in Heat Processed Meat

by Xufang Huang, Wei Sheng, Haonan Chen, Biao Zhang, Na Huang and Shuo Wang

Sensors 2022, 22(1), 8; https://doi.org/10.3390/s22010008 - 21 Dec 2021

Cited by 1 | Viewed by 2551

Abstract

A competitive fluorescence immunoassay for the quantitative detection of 2-amino-3-methylimidazo [4,5-f] quinoline (IQ) in pan-fried meat patties was developed, using magnetic nanoparticles coupled with coating antigen as the capture probe and anti-IQ antibody coupled with NaYF₄: Yb, Er upconversion nanoparticles as [...] Read more.

A competitive fluorescence immunoassay for the quantitative detection of 2-amino-3-methylimidazo [4,5-f] quinoline (IQ) in pan-fried meat patties was developed, using magnetic nanoparticles coupled with coating antigen as the capture probe and anti-IQ antibody coupled with NaYF₄: Yb, Er upconversion nanoparticles as the signal probe. Under optimal conditionals, the wide detection range for IQ in phosphate buffer saline is from 0.01 to 100 μg·L⁻¹ (R² = 0.991) with a detection limit of 0.007 μg·L⁻¹. This proposed method has been applied to detect IQ in two different types of pan-fried meat patties at varying frying times, and the IQ content in chicken patties and fish patties are 2.11–3.47 μg·kg⁻¹ and 1.35–2.85 μg·kg⁻¹, respectively. These results are consistent with that of the ultraperformance liquid chromatography-tandem mass spectrometry. In summary, this method can serve as a sensitive and specific test tool for the determination of IQ in processed meat. Full article

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14 pages, 2074 KiB

Open AccessArticle

A Smartphone-Based Chemosensor to Evaluate Antioxidants in Agri-Food Matrices by In Situ AuNP Formation

by Donato Calabria, Massimo Guardigli, Paolo Severi, Ilaria Trozzi, Andrea Pace, Stefano Cinti, Martina Zangheri and Mara Mirasoli

Sensors 2021, 21(16), 5432; https://doi.org/10.3390/s21165432 - 12 Aug 2021

Cited by 14 | Viewed by 2623

Abstract

In recent years, there has been a continuously growing interest in antioxidants by both customers and food industry. The beneficial health effects of antioxidants led to their widespread use in fortified functional foods, as dietary supplements and as preservatives. A variety of analytical [...] Read more.

In recent years, there has been a continuously growing interest in antioxidants by both customers and food industry. The beneficial health effects of antioxidants led to their widespread use in fortified functional foods, as dietary supplements and as preservatives. A variety of analytical methods are available to evaluate the total antioxidant capacity (TAC) of food extracts and beverages. However, most of them are expensive, time-consuming, and require laboratory instrumentation. Therefore, simple, cheap, and fast portable sensors for point-of-need measurement of antioxidants in food samples are needed. Here, we describe a smartphone-based chemosensor for on-site assessment of TAC of aqueous matrices, relying on the antioxidant-induced formation of gold nanoparticles. The reaction takes place in ready-to-use analytical cartridges containing an hydrogel reaction medium preloaded with Au(III) and is monitored by using the smartphone’s CMOS camera. An analytical device including an LED-based lighting system was developed to ensure uniform and reproducible illumination of the analytical cartridge. The chemosensor permitted rapid TAC measurements of aqueous samples, including teas, herbal infusions, beverages, and extra virgin olive oil extracts, providing results that correlated with those of the reference methods for TAC assessment, e.g., oxygen radical absorbance capacity (ORAC). Full article

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23 pages, 1547 KiB

Open AccessReview

A Review of the Use of Carbon Nanotubes and Graphene-Based Sensors for the Detection of Aflatoxin M1 Compounds in Milk

by Jingrong Gao, Shan He, Anindya Nag and Jonathan Woon Chung Wong

Sensors 2021, 21(11), 3602; https://doi.org/10.3390/s21113602 - 21 May 2021

Cited by 20 | Viewed by 3186

Abstract

This paper presents a comprehensive review of the detection of aflatoxin compounds using carbon allotrope-based sensors. Although aflatoxin M1 and its derivative aflatoxin B1 compounds have been primarily found in milk and other food products, their presence above a threshold concentration causes disastrous [...] Read more.

This paper presents a comprehensive review of the detection of aflatoxin compounds using carbon allotrope-based sensors. Although aflatoxin M1 and its derivative aflatoxin B1 compounds have been primarily found in milk and other food products, their presence above a threshold concentration causes disastrous health-related anomalies in human beings, such as growth impairment, underweight and even carcinogenic and immunosuppressive effects. Among the many sensors developed to detect the presence of these compounds, the employment of certain carbon allotropes, such as carbon nanotubes (CNTs) and graphene, has been highly preferred due to their enhanced electromechanical properties. These conductive nanomaterials have shown excellent quantitative performance in terms of sensitivity and selectivity for the chosen aflatoxin compounds. This paper elucidates some of the significant examples of the CNTs and graphene-based sensors measuring Aflatoxin M1 (ATM1) and Aflatoxin B1 (AFB1) compounds at low concentrations. The fabrication technique and performance of each of the sensors are shown here, as well as some of the challenges existing with the current sensors. Full article

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