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Biosensors, Volume 12, Issue 5 (May 2022) – 102 articles

Cover Story (view full-size image): Our research incorporates the DNA–gold affinity interaction into an electrochemical nucleic-acid-based direct adsorption platform for the voltammetric detection of HOTAIR long noncoding RNA. Our platform utilizes highly specific and sensitive nanomaterials coupled with screen-printed gold electrodes. The assay features three main steps: (i) magnetic bead capture of HOTAIR targets, (ii) magnetic purification and isolation of targets, and (iii) direct adsorption and detection via interfacial affinity interaction. We demonstrate detection as low as 1 pM for samples containing designated proportions of synthetic HOTAIR spiked in buffer as well as healthy plasma samples. Our method shows huge potential in diagnostics due to its disposable, simple, inexpensive, easy-to-store, and portable design. View this paper
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Article
Analysis of Mn2+ and Zn2+ Ions in Macroalgae with Heteroelement-Doped Carbon-Based Fluorescent Probe
Biosensors 2022, 12(5), 359; https://doi.org/10.3390/bios12050359 - 22 May 2022
Viewed by 702
Abstract
Kelp and laver are large economic macroalgae in China, which are rich in nutrients, especially Mn and Zn. Excessive intake of Mn and Zn can be harmful to the human body. Therefore, it is necessary to develop a convenient and efficient method to [...] Read more.
Kelp and laver are large economic macroalgae in China, which are rich in nutrients, especially Mn and Zn. Excessive intake of Mn and Zn can be harmful to the human body. Therefore, it is necessary to develop a convenient and efficient method to detect the contents of Mn and Zn in macroalgae. In this experiment, red carbon dots (R-CDs) doped with N and S elements were prepared by the thermal solvent method. The obtained R-CDs displayed excitation wavelength-independent fluorescent emission in the red spectral region. The R-CDs were used to construct a fluorescent probe for specific recognition of Mn2+ and Zn2+, achieving high-sensitivity detection of Mn2+ and Zn2+. The detection results showed a good linear relationship between fluorescence intensity and Mn2+ concentration, and the calculated detection limit was 0.23 nmol/L. For the detection of Zn2+, the detection limit was estimated as 19.1 nmol/L. At the same time, the content distribution of Mn and Zn elements in macroalgae produced in Fujian was investigated by the constructed fluorescence probe. It was found that kelp, laver, and their products are rich in Mn and Zn elements, and the content of Mn and Zn elements in laver is higher than that in kelp, which can be used as the optimal food supplement for Mn and Zn elements. Full article
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Article
Energy-Efficient, On-Demand Activation of Biosensor Arrays for Long-Term Continuous Health Monitoring
Biosensors 2022, 12(5), 358; https://doi.org/10.3390/bios12050358 - 21 May 2022
Viewed by 642
Abstract
Wearable biosensors for continuous health monitoring, particularly those used for glucose detection, have a limited operational lifetime due to biodegradation and fouling. As a result, patients must change sensors frequently, increasing cost and patient discomfort. Arrays of multiple sensors, where the individual devices [...] Read more.
Wearable biosensors for continuous health monitoring, particularly those used for glucose detection, have a limited operational lifetime due to biodegradation and fouling. As a result, patients must change sensors frequently, increasing cost and patient discomfort. Arrays of multiple sensors, where the individual devices can be activated on demand, increase overall operational longevity, thereby reducing cost and improving patient outcomes. This work demonstrates the feasibility of this approach via decomposition of combustible nitrocellulose membranes that protect the individual sensors from exposure to bioanalytes using a current pulse. Metal contacts, connected by graphene-loaded PEDOT:PSS polymer on the surface of the membrane, deliver the required energy to decompose the membrane. Nitrocellulose membranes with a thickness of less than 1 µm consistently transfer on to polydimethylsiloxane (PDMS) wells. An electrical energy as low as 68 mJ has been shown to suffice for membrane decomposition. Full article
(This article belongs to the Special Issue Device-on-Chip Application in Biomedical Engineering)
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Review
Current Advancements and Future Road Map to Develop ASSURED Microfluidic Biosensors for Infectious and Non-Infectious Diseases
Biosensors 2022, 12(5), 357; https://doi.org/10.3390/bios12050357 - 20 May 2022
Viewed by 793
Abstract
Better diagnostics are always essential for the treatment and prevention of a disease. Existing technologies for detecting infectious and non-infectious diseases are mostly tedious, expensive, and do not meet the World Health Organization’s (WHO) ASSURED (affordable, sensitive, specific, user-friendly, rapid and robust, equipment-free, [...] Read more.
Better diagnostics are always essential for the treatment and prevention of a disease. Existing technologies for detecting infectious and non-infectious diseases are mostly tedious, expensive, and do not meet the World Health Organization’s (WHO) ASSURED (affordable, sensitive, specific, user-friendly, rapid and robust, equipment-free, and deliverable to end user) criteria. Hence, more accurate, sensitive, and faster diagnostic technologies that meet the ASSURED criteria are highly required for timely and evidenced-based treatment. Presently, the diagnostics industry is finding interest in microfluidics-based biosensors, as this integration comprises all qualities, such as reduction in the size of the equipment, rapid turnaround time, possibility of parallel multiple analysis or multiplexing, etc. Microfluidics deal with the manipulation/analysis of fluid within micrometer-sized channels. Biosensors comprise biomolecules immobilized on a physicochemical transducer for the detection of a specific analyte. In this review article, we provide an outline of the history of microfluidics, current practices in the selection of materials in microfluidics, and how and where microfluidics-based biosensors have been used for the diagnosis of infectious and non-infectious diseases. Our inclination in this review article is toward the employment of microfluidics-based biosensors for the improvement of already existing/traditional methods in order to reduce efforts without compromising the accuracy of the diagnostic test. This article also suggests the possible improvements required in microfluidic chip-based biosensors in order to meet the ASSURED criteria. Full article
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Review
Electronic Sensor Technologies in Monitoring Quality of Tea: A Review
Biosensors 2022, 12(5), 356; https://doi.org/10.3390/bios12050356 - 20 May 2022
Viewed by 902
Abstract
Tea, after water, is the most frequently consumed beverage in the world. The fermentation of tea leaves has a pivotal role in its quality and is usually monitored using the laboratory analytical instruments and olfactory perception of tea tasters. Developing electronic sensing platforms [...] Read more.
Tea, after water, is the most frequently consumed beverage in the world. The fermentation of tea leaves has a pivotal role in its quality and is usually monitored using the laboratory analytical instruments and olfactory perception of tea tasters. Developing electronic sensing platforms (ESPs), in terms of an electronic nose (e-nose), electronic tongue (e-tongue), and electronic eye (e-eye) equipped with progressive data processing algorithms, not only can accurately accelerate the consumer-based sensory quality assessment of tea, but also can define new standards for this bioactive product, to meet worldwide market demand. Using the complex data sets from electronic signals integrated with multivariate statistics can, thus, contribute to quality prediction and discrimination. The latest achievements and available solutions, to solve future problems and for easy and accurate real-time analysis of the sensory-chemical properties of tea and its products, are reviewed using bio-mimicking ESPs. These advanced sensing technologies, which measure the aroma, taste, and color profiles and input the data into mathematical classification algorithms, can discriminate different teas based on their price, geographical origins, harvest, fermentation, storage times, quality grades, and adulteration ratio. Although voltammetric and fluorescent sensor arrays are emerging for designing e-tongue systems, potentiometric electrodes are more often employed to monitor the taste profiles of tea. The use of a feature-level fusion strategy can significantly improve the efficiency and accuracy of prediction models, accompanied by the pattern recognition associations between the sensory properties and biochemical profiles of tea. Full article
(This article belongs to the Special Issue Biosensors in 2022)
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Article
An Artifact-Resistant Feature SKNAER for Quantifying the Burst of Skin Sympathetic Nerve Activity Signal
Biosensors 2022, 12(5), 355; https://doi.org/10.3390/bios12050355 - 20 May 2022
Cited by 1 | Viewed by 547
Abstract
Evaluation of sympathetic nerve activity (SNA) using skin sympathetic nerve activity (SKNA) signal has attracted interest in recent studies. However, signal noises may obstruct the accurate location for the burst of SKNA, leading to the quantification error of the signal. In this study, [...] Read more.
Evaluation of sympathetic nerve activity (SNA) using skin sympathetic nerve activity (SKNA) signal has attracted interest in recent studies. However, signal noises may obstruct the accurate location for the burst of SKNA, leading to the quantification error of the signal. In this study, we use the Teager–Kaiser energy (TKE) operator to preprocess the SKNA signal, and then candidates of burst areas were segmented by an envelope-based method. Since the burst of SKNA can also be discriminated by the high-frequency component in QRS complexes of electrocardiogram (ECG), a strategy was designed to reject their influence. Finally, a feature of the SKNA energy ratio (SKNAER) was proposed for quantifying the SKNA. The method was verified by both sympathetic nerve stimulation and hemodialysis experiments compared with traditional heart rate variability (HRV) and a recently developed integral skin sympathetic nerve activity (iSKNA) method. The results showed that SKNAER correlated well with HRV features (r = 0.60 with the standard deviation of NN intervals, 0.67 with low frequency/high frequency, 0.47 with very low frequency) and the average of iSKNA (r = 0.67). SKNAER improved the detection accuracy for the burst of SKNA, with 98.2% for detection rate and 91.9% for precision, inducing increases of 3.7% and 29.1% compared with iSKNA (detection rate: 94.5% (p < 0.01), precision: 62.8% (p < 0.001)). The results from the hemodialysis experiment showed that SKNAER had more significant differences than aSKNA in the long-term SNA evaluation (p < 0.001 vs. p = 0.07 in the fourth period, p < 0.01 vs. p = 0.11 in the sixth period). The newly developed feature may play an important role in continuously monitoring SNA and keeping potential for further clinical tests. Full article
(This article belongs to the Special Issue Intelligent Biosignal Processing in Wearable and Implantable Sensors)
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Article
Acetone Gas Sensor Based on SWCNT/Polypyrrole/Phenyllactic Acid Nanocomposite with High Sensitivity and Humidity Stability
Biosensors 2022, 12(5), 354; https://doi.org/10.3390/bios12050354 - 19 May 2022
Viewed by 562
Abstract
We synthesized core-shell-shaped nanocomposites composed of a single-walled carbon nanotube (SWCNT) and heptadecafluorooctanesulfonic acid-doped polypyrrole (C8F-doped-PPy)/phenyllatic acid (PLA), i.e., C8F-doped-PPy/[email protected], for detecting acetone gas with high sensitivity and humidity stability. The obtained nanocomposites have the structural features of a sensing material as a [...] Read more.
We synthesized core-shell-shaped nanocomposites composed of a single-walled carbon nanotube (SWCNT) and heptadecafluorooctanesulfonic acid-doped polypyrrole (C8F-doped-PPy)/phenyllatic acid (PLA), i.e., C8F-doped-PPy/[email protected], for detecting acetone gas with high sensitivity and humidity stability. The obtained nanocomposites have the structural features of a sensing material as a C8F-doped-PPy layer surrounding a single-stranded SWCNT, and a PLA layer on the outer surface of the PPy as a specific sensing layer for acetone. PLA was chemically combined with the positively charged PPy backbone and provided the ability to reliably detect acetone gas at concentrations as low as 50 ppb even at 25 °C, which is required for medical diagnoses via human breath analysis. When C8F was contained in the pyrrole monomer in a ratio of 0.1 mol, it was able to stably detect an effective signal in a relative humidity (RH) of 0–80% range. Full article
(This article belongs to the Special Issue Application of Nanomaterials for Biosensors)
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Article
Bioluminescent-Inhibition-Based Biosensor for Full-Profile Soil Contamination Assessment
Biosensors 2022, 12(5), 353; https://doi.org/10.3390/bios12050353 - 19 May 2022
Viewed by 534
Abstract
A bioluminescent-enzyme-inhibition-based assay was applied to predict the potential toxicity of the full profile of the following soil samples: agricultural grassland, 10-year fallow land (treated with remediation processes for 10 years) and uncontaminated (virgin) land. This assay specifically detects the influence of aqueous [...] Read more.
A bioluminescent-enzyme-inhibition-based assay was applied to predict the potential toxicity of the full profile of the following soil samples: agricultural grassland, 10-year fallow land (treated with remediation processes for 10 years) and uncontaminated (virgin) land. This assay specifically detects the influence of aqueous soil extracts from soils on the activity of a coupled enzyme system of luminescent bacteria: NAD(P)H:FMN-oxidoreductase + luciferase (Red + Luc). It was shown that the inhibitory effect of the full-profile soil samples on the Red + Luc system decreased with depth for the 10-year fallow-land and virgin-land samples, which correlated with a decrease in the humic organic matter content in the soils. The inhibitory effect of the agricultural grassland on the Red + Luc enzyme system activity was more complex and involved the presence of the humic organic matter content, as well as the presence of pollutants in the whole-soil profile. However, if the interfering effect of humic organic substances on the Red + Luc system’s activity is taken into account during full-profile soil toxicity assessments, it might help to detect pollutant mobility and its leaching into the subsoil layer. Thus, this bioluminescent method, due to the technical simplicity, rapid response time and high sensitivity, has the potential to be developed as a biological part of the inhibition-based assay and/or biosensors for the preventive tracing of potential full-profile soil contamination. Full article
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Article
Fiber-Optic Distributed Sensing Network for Thermal Mapping of Gold Nanoparticles-Mediated Radiofrequency Ablation
Biosensors 2022, 12(5), 352; https://doi.org/10.3390/bios12050352 - 18 May 2022
Viewed by 540
Abstract
In this work, we report the design of an optical fiber distributed sensing network for the 2-dimensional (2D) in situ thermal mapping of advanced methods for radiofrequency thermal ablation. The sensing system is based on six high-scattering MgO-doped optical fibers, interleaved by a [...] Read more.
In this work, we report the design of an optical fiber distributed sensing network for the 2-dimensional (2D) in situ thermal mapping of advanced methods for radiofrequency thermal ablation. The sensing system is based on six high-scattering MgO-doped optical fibers, interleaved by a scattering-level spatial multiplexing approach that allows simultaneous detection of each fiber location, in a 40 × 20 mm grid (7.8 mm2 pixel size). Radiofrequency ablation (RFA) was performed on bovine phantom, using a pristine approach and methods mediated by agarose and gold nanoparticles in order to enhance the ablation properties. The 2D sensors allow the detection of spatiotemporal patterns, evaluating the heating properties and investigating the repeatability. We observe that agarose-based ablation yields the widest ablated area in the best-case scenario, while gold nanoparticles-mediated ablation provides the best trade-off between the ablated area (53.0–65.1 mm2, 61.5 mm2 mean value) and repeatability. Full article
(This article belongs to the Special Issue Photonics for Bioapplications: Sensors and Technology)
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Article
Investigation and Comparison of Specific Antibodies’ Affinity Interaction with SARS-CoV-2 Wild-Type, B.1.1.7, and B.1.351 Spike Protein by Total Internal Reflection Ellipsometry
Biosensors 2022, 12(5), 351; https://doi.org/10.3390/bios12050351 - 18 May 2022
Cited by 2 | Viewed by 595
Abstract
SARS-CoV-2 vaccines provide strong protection against COVID-19. However, the emergence of SARS-CoV-2 variants has raised concerns about the efficacy of vaccines. In this study, we investigated the interactions of specific polyclonal human antibodies (pAb-SCoV2-S) produced after vaccination with the Vaxzevria vaccine with the [...] Read more.
SARS-CoV-2 vaccines provide strong protection against COVID-19. However, the emergence of SARS-CoV-2 variants has raised concerns about the efficacy of vaccines. In this study, we investigated the interactions of specific polyclonal human antibodies (pAb-SCoV2-S) produced after vaccination with the Vaxzevria vaccine with the spike proteins of three SARS-CoV-2 variants of concern: wild-type, B.1.1.7, and B.1.351. Highly sensitive, label-free, and real-time monitoring of these interactions was accomplished using the total internal reflection ellipsometry method. Thermodynamic parameters such as association and dissociation rate constants, the stable immune complex formation rate constant (kr), the equilibrium association and dissociation (KD) constants and steric factors (Ps) were calculated using a two-step irreversible binding mathematical model. The results obtained show that the KD values for the specific antibody interactions with all three types of spike protein are in the same nanomolar range. The KD values for B.1.1.7 and B.1.351 suggest that the antibody produced after vaccination can successfully protect the population from the alpha (B.1.1.7) and beta (B.1.351) SARS-CoV-2 mutations. The steric factors (Ps) obtained for all three types of spike proteins showed a 100-fold lower requirement for the formation of an immune complex when compared with nucleocapsid protein. Full article
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Article
Easy-to-Operate Co-Flow Step Emulsification Device for High-Throughput Three-Dimensional Cell Culture
Biosensors 2022, 12(5), 350; https://doi.org/10.3390/bios12050350 - 18 May 2022
Viewed by 589
Abstract
Cell culture plays an essential role in tissue engineering and high-throughput drug screening. Compared with two-dimensional (2D) in vitro culture, three-dimensional (3D) in vitro culture can mimic cells in vivo more accurately, including complex cellular organizations, heterogeneity, and cell–extracellular matrix (ECM) interactions. This [...] Read more.
Cell culture plays an essential role in tissue engineering and high-throughput drug screening. Compared with two-dimensional (2D) in vitro culture, three-dimensional (3D) in vitro culture can mimic cells in vivo more accurately, including complex cellular organizations, heterogeneity, and cell–extracellular matrix (ECM) interactions. This article presents a droplet-based microfluidic chip that integrates cell distribution, 3D in vitro cell culture, and in situ cell monitoring in a single device. Using the microfluidic “co-flow step emulsification” approach, we have successfully prepared close-packed droplet arrays with an ultra-high-volume fraction (72%) which can prevent cells from adhering to the chip surface so as to achieve a 3D cell culture and make scalable and high-throughput cell culture possible. The proposed device could produce droplets from 55.29 ± 1.52 to 95.64 ± 3.35 μm, enabling the diverse encapsulation of cells of different sizes and quantities. Furthermore, the cost for each microfluidic CFSE chip is approximately USD 3, making it a low-cost approach for 3D cell culture. The proposed device is successfully applied in the 3D culture of saccharomyces cerevisiae cells with an occurrence rate for proliferation of 80.34 ± 3.77%. With low-cost, easy-to-operate, high-throughput, and miniaturization characteristics, the proposed device meets the requirements for 3D in vitro cell culture and is expected to be applied in biological fields such as drug toxicology and pharmacokinetics. Full article
(This article belongs to the Collection Microsystems for Cell Cultures)
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Brief Report
How Paretic and Non-Paretic Ankle Muscles Contract during Walking in Stroke Survivors: New Insight Using Novel Wearable Ultrasound Imaging and Sensing Technology
Biosensors 2022, 12(5), 349; https://doi.org/10.3390/bios12050349 - 18 May 2022
Cited by 1 | Viewed by 634
Abstract
Abnormal muscle tone and muscle weakness are related to gait asymmetry in stroke survivors. However, the internal muscle morphological changes that occur during walking remain unclear. To address this issue, this study investigated the muscle activity of the tibialis anterior (TA) and medial [...] Read more.
Abnormal muscle tone and muscle weakness are related to gait asymmetry in stroke survivors. However, the internal muscle morphological changes that occur during walking remain unclear. To address this issue, this study investigated the muscle activity of the tibialis anterior (TA) and medial gastrocnemius (MG) of both the paretic and non-paretic sides during walking in nine stroke survivors, by simultaneously capturing electromyography (EMG), mechanomyography (MMG), and ultrasound images, and using a validated novel wearable ultrasound imaging and sensing system. Statistical analysis was performed to examine the test–retest reliability of the collected data, and both the main and interaction effects of each “side” (paretic vs. non-paretic) and “gait” factors, in stroke survivors. This study observed significantly good test–retest reliability in the collected data (0.794 ≤ ICC ≤ 0.985), and significant differences existed in both the side and gait factors of the average TA muscle thickness from ultrasound images, and in the gait factors of TA and MG muscle’s MMG and EMG signals (p < 0.05). The muscle morphological characteristics also appeared to be different between the paretic and non-paretic sides on ultrasound images. This study uncovered significantly different internal muscle contraction patterns between paretic and non-paretic sides during walking for TA (7.2% ± 1.6%) and MG (5.3% ± 4.9%) muscles in stroke survivors. Full article
(This article belongs to the Section Biosensors and Healthcare)
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Review
AIE-Active Photosensitizers: Manipulation of Reactive Oxygen Species Generation and Applications in Photodynamic Therapy
Biosensors 2022, 12(5), 348; https://doi.org/10.3390/bios12050348 - 18 May 2022
Viewed by 653
Abstract
Photodynamic therapy (PDT) is a non-invasive approach for tumor elimination that is attracting more and more attention due to the advantages of minimal side effects and high precision. In typical PDT, reactive oxygen species (ROS) generated from photosensitizers play the pivotal role, determining [...] Read more.
Photodynamic therapy (PDT) is a non-invasive approach for tumor elimination that is attracting more and more attention due to the advantages of minimal side effects and high precision. In typical PDT, reactive oxygen species (ROS) generated from photosensitizers play the pivotal role, determining the efficiency of PDT. However, applications of traditional PDT were usually limited by the aggregation-caused quenching (ACQ) effect of the photosensitizers employed. Fortunately, photosensitizers with aggregation-induced emission (AIE-active photosensitizers) have been developed with biocompatibility, effective ROS generation, and superior absorption, bringing about great interest for applications in oncotherapy. In this review, we review the development of AIE-active photosensitizers and describe molecule and aggregation strategies for manipulating photosensitization. For the molecule strategy, we describe the approaches utilized for tuning ROS generation by attaching heavy atoms, constructing a donor-acceptor effect, introducing ionization, and modifying with activatable moieties. The aggregation strategy to boost ROS generation is reviewed for the first time, including consideration of the aggregation of photosensitizers, polymerization, and aggregation microenvironment manipulation. Moreover, based on AIE-active photosensitizers, the cutting-edge applications of PDT with NIR irradiated therapy, activatable therapy, hypoxic therapy, and synergistic treatment are also outlined. Full article
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Article
An Aptamer-Functionalised Schottky-Field Effect Transistor for the Detection of Proteins
Biosensors 2022, 12(5), 347; https://doi.org/10.3390/bios12050347 - 18 May 2022
Viewed by 666
Abstract
The outbreak of the coronavirus disease 2019 (COVID-19) in December 2019 has highlighted the need for a flexible sensing system that can quickly and accurately determine the presence of biomarkers associated with the disease. This sensing system also needs to be easily adaptable [...] Read more.
The outbreak of the coronavirus disease 2019 (COVID-19) in December 2019 has highlighted the need for a flexible sensing system that can quickly and accurately determine the presence of biomarkers associated with the disease. This sensing system also needs to be easily adaptable to incorporate both novel diseases as well as changes in the existing ones. Here we report the feasibility of using a simple, low-cost silicon field-effect transistor functionalised with aptamers and designed to attach to the spike protein of SARS-CoV2. It is shown that a linear response can be obtained in a concentration range of 100 fM to 10 pM. Furthermore, by using a larger range of source-drain potentials compared with other FET based sensors, it is possible to look at a wider range of device parameters to optimise the response. Full article
(This article belongs to the Special Issue Feature Issue of Biosensors and Bioelectronic Devices Section)
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Article
Kinetics of Isothermal Dumbbell Exponential Amplification: Effects of Mix Composition on LAMP and Its Derivatives
Biosensors 2022, 12(5), 346; https://doi.org/10.3390/bios12050346 - 18 May 2022
Viewed by 562
Abstract
Loop-mediated isothermal amplification (LAMP) is an exponential amplification method of DNA strands that is more and more used for its high performances. Thanks to its high sensitivity and selectivity, LAMP found numerous applications from the detection of pathogens or viruses through their genome [...] Read more.
Loop-mediated isothermal amplification (LAMP) is an exponential amplification method of DNA strands that is more and more used for its high performances. Thanks to its high sensitivity and selectivity, LAMP found numerous applications from the detection of pathogens or viruses through their genome amplification to its incorporation as an amplification strategy in protein or miRNA biomarker quantification. The LAMP method is composed of two stages: the first one consists in the transformation of the DNA strands into dumbbell structures formed of two stems and loops thanks to four primers; then, in the second stage, only two primers are required to amplify the dumbbells exponentially in numerous hairpins of increasing lengths. In this paper, we propose a theoretical framework to analyze the kinetics of the second stage of LAMP, the isothermal dumbbell exponential amplification (IDEA) as function of the physico-chemical parameters of the amplification reaction. Dedicated experiments validate the models. We believe these results may help the optimization of LAMP performances by reducing the number of experiments necessary to find the best parameters. Full article
(This article belongs to the Special Issue Advances in Amplification Methods for Biosensors)
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Article
Analyzing Human Periodontal Soft Tissue Inflammation and Drug Responses In Vitro Using Epithelium-Capillary Interface On-a-Chip
Biosensors 2022, 12(5), 345; https://doi.org/10.3390/bios12050345 - 18 May 2022
Viewed by 608
Abstract
The gingival epithelium–capillary interface is a unique feature of periodontal soft tissue, preserving periodontal tissue homeostasis and preventing microorganism and toxic substances from entering the subepithelial tissue. However, the function of the interface is disturbed in periodontitis, and mechanisms of the breakdown of [...] Read more.
The gingival epithelium–capillary interface is a unique feature of periodontal soft tissue, preserving periodontal tissue homeostasis and preventing microorganism and toxic substances from entering the subepithelial tissue. However, the function of the interface is disturbed in periodontitis, and mechanisms of the breakdown of the interface are incompletely understood. To address these limitations, we developed a microfluidic epithelium–capillary barrier with a thin culture membrane (10 μm) that closely mimics the in vivo gingival epithelial barrier with an immune micro-environment. To test the validity of the fabricated gingival epithelial barrier model, epithelium–capillary interface-on-a-chip was cultured with human gingival epithelial cells (HGECs) and human vascular endothelial cells (HUVEC). Their key properties were tested using optical microscope, transepithelial/transendothelial electrical resistance (TEER), and permeability assays. The clear expression of VE-cadherin revealed the tight junctions in endothelial cells. Live/dead assays indicated a high cell viability, and the astrocytic morphology of HGE cells was confirmed by F-actin immunostaining. By the third day of cell culture, TEER levels typically exceeded in co-cultures. The resultant permeability coefficients showed a significant difference between 70 kDa and 40 kDa FITC-dextran. The expression of protein intercellular cell adhesion molecule (ICAM-1) and human beta defensin-2 (HBD2) decreased when exposed to TNF-α and LPS, but recovered with the NF-κB inhibitor treatment- Pyrrolidinedithiocarbamic acid (PDTC), indicating the stability of the fabricated chip. These results demonstrate that the developed epithelium-capillary interface system is a valid model for studying periodontal soft tissue function and drug delivery. Full article
(This article belongs to the Special Issue Microfluidic Based Organ-on-Chips and Biomedical Application)
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Review
Diagnoses Based on C-Reactive Protein Point-of-Care Tests
Biosensors 2022, 12(5), 344; https://doi.org/10.3390/bios12050344 - 17 May 2022
Viewed by 559
Abstract
C-reactive protein (CRP) is an important part of the immune system’s reaction to various pathological impulses such as bacterial infections, systemic inflammation, and internal organ failures. An increased CRP level serves to diagnose the mentioned pathological states. Both standard laboratory methods and simple [...] Read more.
C-reactive protein (CRP) is an important part of the immune system’s reaction to various pathological impulses such as bacterial infections, systemic inflammation, and internal organ failures. An increased CRP level serves to diagnose the mentioned pathological states. Both standard laboratory methods and simple point-of-care devices such as lateral flow tests and immunoturbidimetric assays serve for the instrumental diagnoses based on CRP. The current method for CRP has many flaws and limitations in its use. Biosensor and bioassay analytical devices are presently researched by many teams to provide more sensitive and better-suited tools for point-of-care tests of CRP in biological samples when compared to the standard methods. This review article is focused on mapping the diagnostical relevance of CRP, the applicability of the current analytical methods, and the recent innovations in the measurement of CRP level. Full article
(This article belongs to the Section Biosensor and Bioelectronic Devices)
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Article
Double Competitive Immunodetection of Small Analyte: Realization for Highly Sensitive Lateral Flow Immunoassay of Chloramphenicol
Biosensors 2022, 12(5), 343; https://doi.org/10.3390/bios12050343 - 17 May 2022
Viewed by 557
Abstract
A new scheme of reagents interaction for lateral flow immunoassay (LFIA) is proposed, which combines the features of competitive and sandwich assay and provides highly sensitive detection of low-molecular-weight analytes. Namely, the antigen in the sample interferes with the formation of the antibody [...] Read more.
A new scheme of reagents interaction for lateral flow immunoassay (LFIA) is proposed, which combines the features of competitive and sandwich assay and provides highly sensitive detection of low-molecular-weight analytes. Namely, the antigen in the sample interferes with the formation of the antibody (on the membrane)–hapten-protein–antibody (on the nanoparticle-marker) complex, competing with hapten-protein conjugate in both reactions. The proposed scheme was modelled using COPASI software, with a prediction of limit of detection (LOD) decrease by one order of magnitude compared to the standard competitive LFIA. This feature was experimentally confirmed for the detection of chloramphenicol (CAP) in honey. When tested in spiked honey, the visual LOD was 50 ng/mL for the common scheme and 5 ng/mL for the proposed scheme. Instrumental LOD was 300 pg/mL (1.2 µg/kg in conversion per sample weight of honey) in the standard scheme and 20 pg/mL (80 ng/kg in conversion per sample weight of honey) in the proposed scheme. Full article
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Review
Targeted Molecular Imaging Probes Based on Magnetic Resonance Imaging for Hepatocellular Carcinoma Diagnosis and Treatment
Biosensors 2022, 12(5), 342; https://doi.org/10.3390/bios12050342 - 17 May 2022
Viewed by 578
Abstract
Hepatocellular carcinoma (HCC) is the sixth most commonly malignant tumor and the third leading cause of cancer-related death in the world, and the early diagnosis and treatment of patients with HCC is core in improving its prognosis. The early diagnosis of HCC depends [...] Read more.
Hepatocellular carcinoma (HCC) is the sixth most commonly malignant tumor and the third leading cause of cancer-related death in the world, and the early diagnosis and treatment of patients with HCC is core in improving its prognosis. The early diagnosis of HCC depends largely on magnetic resonance imaging (MRI). MRI has good soft-tissue resolution, which is the international standard method for the diagnosis of HCC. However, MRI is still insufficient in the diagnosis of some early small HCCs and malignant nodules, resulting in false negative results. With the deepening of research on HCC, researchers have found many specific molecular biomarkers on the surface of HCC cells, which may assist in diagnosis and treatment. On the other hand, molecular imaging has progressed rapidly in recent years, especially in the field of cancer theranostics. Hence, the preparation of molecular imaging probes that can specifically target the biomarkers of HCC, combined with MRI testing in vivo, may achieve the theranostic purpose of HCC in the early stage. Therefore, in this review, taking MR imaging as the basic point, we summarized the recent progress regarding the molecular imaging targeting various types of biomarkers on the surface of HCC cells to improve the theranostic rate of HCC. Lastly, we discussed the existing obstacles and future prospects of developing molecular imaging probes as HCC theranostic nanoplatforms. Full article
(This article belongs to the Special Issue Advances in Nanomedicines for Disease Diagnosis and Therapeutics)
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Article
Solving Color Reproducibility between Digital Devices: A Robust Approach of Smartphones Color Management for Chemical (Bio)Sensors
Biosensors 2022, 12(5), 341; https://doi.org/10.3390/bios12050341 - 17 May 2022
Viewed by 523
Abstract
In the past twelve years, digital image colorimetry (DIC) on smartphones has acquired great importance as an alternative to the most common analytical techniques. This analysis method is based on fast, low-cost, and easily-accessible technology, which can provide quantitative information about an analyte [...] Read more.
In the past twelve years, digital image colorimetry (DIC) on smartphones has acquired great importance as an alternative to the most common analytical techniques. This analysis method is based on fast, low-cost, and easily-accessible technology, which can provide quantitative information about an analyte through the color changes of a digital image. Despite the fact that DIC is very widespread, it is not exempt from a series of problems that are not fully resolved yet, such as variability of the measurements between smartphones, image format in which color information is stored, power distribution of the illuminant used for the measurements, among others. This article proposes a methodology for the standardization and correction of these problems using self-developed software, together with the use of a 3D printed light box. This methodology is applied to three different colorimetric analyses using different types and brands of smartphones, proving that comparable measurements between devices can be achieved. As color can be related to many target analytes, establishing this measurement methodology can lead to new control analysis applicable to diverse sectors such as alimentary, industrial, agrarian, or sanitary. Full article
(This article belongs to the Special Issue Smartphone-Based Sensors for Biomedical Applications)
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Article
Bead Number Effect in a Magnetic-Beads-Based Digital Microfluidic Immunoassay
Biosensors 2022, 12(5), 340; https://doi.org/10.3390/bios12050340 - 16 May 2022
Viewed by 546
Abstract
In a biomedical diagnosis with a limited sample volume and low concentration, droplet-based microfluidics, also called digital microfluidics, becomes a very attractive approach. Previously, our group developed a magnetic-beads-based digital microfluidic immunoassay with a bead number of around 100, requiring less than 1 [...] Read more.
In a biomedical diagnosis with a limited sample volume and low concentration, droplet-based microfluidics, also called digital microfluidics, becomes a very attractive approach. Previously, our group developed a magnetic-beads-based digital microfluidic immunoassay with a bead number of around 100, requiring less than 1 μL of sample volume to achieve a pg/mL level limit of detection (LOD). However, the bead number in each measurement was not the same, causing an unstable coefficient of variation (CV) in the calibration curve. Here, we investigated whether a fixed number of beads in this bead-based digital microfluidic immunoassay could provide more stable results. First, the bead screening chips were developed to extract exactly 100, 49, and 25 magnetic beads with diameters of less than 6 μm. Then, four calibration curves were established. One calibration curve was constructed by using varying bead numbers (50–160) in the process. The other three calibration curves used a fixed number of beads, (100, 49, and 25). The results indicated that the CVs for a fixed number of beads were evidently smaller than the CVs for varying bead numbers, especially in the range of 1 pg/mL to 100 pg/mL, where the CVs for 100 beads were less than 10%. Furthermore, the calculated LOD, based on the composite calibration curves, could be reduced by three orders, from 3.0 pg/mL (for the unfixed bead number) to 0.0287 pg/mL (for 100 beads). However, when the bead numbers were too high (more than 500) or too low (25 or fewer), the bead manipulation for aggregation became more difficult in the magnetic-beads-based digital microfluidic immunoassay chip. Full article
(This article belongs to the Special Issue Biosensors Based on Microfluidic Devices)
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Article
Portable Respiration Monitoring System with an Embroidered Capacitive Facemask Sensor
Biosensors 2022, 12(5), 339; https://doi.org/10.3390/bios12050339 - 15 May 2022
Viewed by 663
Abstract
Respiration monitoring is a very important indicator of health status. It can be used as a marker in the recognition of a variety of diseases, such as sleep apnea, asthma or cardiac arrest. The purpose of the present study is to overcome limitations [...] Read more.
Respiration monitoring is a very important indicator of health status. It can be used as a marker in the recognition of a variety of diseases, such as sleep apnea, asthma or cardiac arrest. The purpose of the present study is to overcome limitations of the current state of the art in the field of respiration monitoring systems. Our goal was the development of a lightweight handheld device with portable operation and low power consumption. The proposed approach includes a textile capacitive sensor with interdigitated electrodes embroidered into the facemask, integrated with readout electronics. Readout electronics is based on the direct interface of the capacitive sensor and a microcontroller through just one analog and one digital pin. The microcontroller board and sensor are powered by a smartphone or PC through a USB cable. The developed mobile application for the Android™ operating system offers reliable data acquisition and acts as a bridge for data transfer to the remote server. The embroidered sensor was initially tested in a humidity-controlled chamber connected to a commercial impedance analyzer. Finally, in situ testing with 10 volunteering subjects confirmed stable operation with reliable respiration monitoring. Full article
(This article belongs to the Special Issue Electrochemical (Bio)Sensors and Energy Autonomous Sensing System)
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Communication
Establishment and Comparative Analysis of Enzyme-Linked Immunoassay and Time-Resolved Fluoroimmunoassay for the Determination of Trace Quinclorac in Environment
Biosensors 2022, 12(5), 338; https://doi.org/10.3390/bios12050338 - 14 May 2022
Viewed by 553
Abstract
As a common herbicide in farmland, there has been wide concern over quinclorac residue because of its potential risks to the environment and human health. For the detection and monitoring of quinclorac residue in the environment, enzyme-linked immunoassay (ELISA) and time-resolved fluoroimmunoassay (TRFIA) [...] Read more.
As a common herbicide in farmland, there has been wide concern over quinclorac residue because of its potential risks to the environment and human health. For the detection and monitoring of quinclorac residue in the environment, enzyme-linked immunoassay (ELISA) and time-resolved fluoroimmunoassay (TRFIA) were established. The half-maximal inhibition concentrations (IC50) of ELISA and TRFIA were 0.169 mg/L and 0.087 mg/L with a linear range (IC20–IC80) of 0.020–1.389 mg/L and 0.004–1.861 mg/L, respectively. Compared with ELISA, the limit of detection (LOD, IC20) and IC50 of TRFIA improved approximately 5-fold and 2-fold. The cross-reaction rates for the quinclorac analogs were less than 2%. The average recoveries of quinclorac in river water, paddy water, paddy soil, and brown rice samples were 77.3–106.1%, with RSDs of 1.7–12.5%. More importantly, the results of the two methods were consistent with that of the referenced method of UPLC-MS/MS (R2 > 0.98). ELISA and TRFIA both showed good detection performance and could meet the requirements of the quantitative determination of quinclorac. Therefore, the proposed ELISA and TRFIA could be applied to the rapid and sensitive detection and monitoring of quinclorac residue in the environment. Full article
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Article
Multilayered Mesoporous Composite Nanostructures for Highly Sensitive Label-Free Quantification of Cardiac Troponin-I
Biosensors 2022, 12(5), 337; https://doi.org/10.3390/bios12050337 - 14 May 2022
Viewed by 785
Abstract
Cardiac troponin-I (cTnI) is a well-known biomarker for the diagnosis and control of acute myocardial infarction in clinical practice. To improve the accuracy and reliability of cTnI electrochemical immunosensors, we propose a multilayer nanostructure consisting of Fe3O4-COOH labeled anti-cTnI [...] Read more.
Cardiac troponin-I (cTnI) is a well-known biomarker for the diagnosis and control of acute myocardial infarction in clinical practice. To improve the accuracy and reliability of cTnI electrochemical immunosensors, we propose a multilayer nanostructure consisting of Fe3O4-COOH labeled anti-cTnI monoclonal antibody (Fe3O4-COOH-Ab1) and anti-cTnI polyclonal antibody (Ab2) conjugated on Au-Ag nanoparticles (NPs) decorated on a metal–organic framework ([email protected]2). In this design, Fe3O4-COOH was used for separation of cTnI in specimens and signal amplification, hierarchical porous ZIF-67 extremely enhanced the specific surface area, and Au-Ag NPs synergically promoted the conductivity and sensitivity. They were additionally employed as an immobilization platform to enhance antibody loading. Electron microscopy images indicated that Ag-Au NPs with an average diameter of 1.9 ± 0.5 nm were uniformly decorated on plate-like ZIF-67 particles (with average size of 690 nm) without any agglomeration. Several electrochemical assays were implemented to precisely evaluate the immunosensor performance. The square wave voltammetry technique exhibited the best performance with a sensitivity of 0.98 mA mL cm−2 ng−1 and a detection limit of 0.047 pg mL−1 in the linear range of 0.04 to 8 ng mL−1. Full article
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Review
Assessment of Nanoparticle-Mediated Tumor Oxygen Modulation by Photoacoustic Imaging
Biosensors 2022, 12(5), 336; https://doi.org/10.3390/bios12050336 - 13 May 2022
Viewed by 624
Abstract
Photoacoustic imaging (PAI) is an invaluable tool in biomedical imaging, as it provides anatomical and functional information in real time. Its ability to image at clinically relevant depths with high spatial resolution using endogenous tissues as contrast agents constitutes its major advantage. One [...] Read more.
Photoacoustic imaging (PAI) is an invaluable tool in biomedical imaging, as it provides anatomical and functional information in real time. Its ability to image at clinically relevant depths with high spatial resolution using endogenous tissues as contrast agents constitutes its major advantage. One of the most important applications of PAI is to quantify tissue oxygen saturation by measuring the differential absorption characteristics of oxy and deoxy Hb. Consequently, PAI can be utilized to monitor tumor-related hypoxia, which is a crucial factor in tumor microenvironments that has a strong influence on tumor invasiveness. Reactive oxygen species (ROS)-based therapies, such as photodynamic therapy, radiotherapy, and sonodynamic therapy, are oxygen-consuming, and tumor hypoxia is detrimental to their efficacy. Therefore, a persistent demand exists for agents that can supply oxygen to tumors for better ROS-based therapeutic outcomes. Among the various strategies, NP-mediated supplemental tumor oxygenation is especially encouraging due to its physio-chemical, tumor targeting, and theranostic properties. Here, we focus on NP-based tumor oxygenation, which includes NP as oxygen carriers and oxygen-generating strategies to alleviate hypoxia monitored by PAI. The information obtained from quantitative tumor oxygenation by PAI not only supports optimal therapeutic design but also serves as a highly effective tool to predict therapeutic outcomes. Full article
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Article
Functionalization of Glucose Oxidase in Organic Solvent: Towards Direct Electrical Communication across Enzyme-Electrode Interface
Biosensors 2022, 12(5), 335; https://doi.org/10.3390/bios12050335 - 13 May 2022
Viewed by 545
Abstract
Enzymatic biosensors based on glucose oxidase has been proven to be one of the effective strategies for the detection of glucose and contributed to health improvements. Therefore, research and debates to date are ongoing in an attempt to find the most effective way [...] Read more.
Enzymatic biosensors based on glucose oxidase has been proven to be one of the effective strategies for the detection of glucose and contributed to health improvements. Therefore, research and debates to date are ongoing in an attempt to find the most effective way to detect this analyte using this enzyme as the recognition center. The 3rd generation biosensors using direct electron transfer (DET) type enzymes are a great way towards practical devices. In this work, we developed a simple method for the functionalization of glucose oxidase with redoxable ferrocene groups in chloroform. The enzyme retained its activity after storage in this organic solvent and after the functionalization procedures. This enzyme functionalization strategy was employed to develop the biosensing monolayer-based platforms for the detection of glucose utilizing the quasi-DET mechanism. As a result of an electrochemical regeneration of the catalytic center, the formation of harmful H2O2 is minimized during enzymatic electrocatalysis. Full article
(This article belongs to the Special Issue Electrochemistry and Spectroscopy-Based Biosensors)
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Article
Field-Effect Capacitors Decorated with Ligand-Stabilized Gold Nanoparticles: Modeling and Experiments
Biosensors 2022, 12(5), 334; https://doi.org/10.3390/bios12050334 - 13 May 2022
Viewed by 612
Abstract
Nanoparticles are recognized as highly attractive tunable materials for designing field-effect biosensors with enhanced performance. In this work, we present a theoretical model for electrolyte-insulator-semiconductor capacitors (EISCAP) decorated with ligand-stabilized charged gold nanoparticles. The charged AuNPs are taken into account as additional, nanometer-sized [...] Read more.
Nanoparticles are recognized as highly attractive tunable materials for designing field-effect biosensors with enhanced performance. In this work, we present a theoretical model for electrolyte-insulator-semiconductor capacitors (EISCAP) decorated with ligand-stabilized charged gold nanoparticles. The charged AuNPs are taken into account as additional, nanometer-sized local gates. The capacitance-voltage (CV) curves and constant-capacitance (ConCap) signals of the AuNP-decorated EISCAPs have been simulated. The impact of the AuNP coverage on the shift of the CV curves and the ConCap signals was also studied experimentally on Al–p-Si–SiO2 EISCAPs decorated with positively charged aminooctanethiol-capped AuNPs. In addition, the surface of the EISCAPs, modified with AuNPs, was characterized by scanning electron microscopy for different immobilization times of the nanoparticles. Full article
(This article belongs to the Special Issue Biosensors in Nanotechnology)
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Article
A Patient-Ready Wearable Transcutaneous CO2 Sensor
Biosensors 2022, 12(5), 333; https://doi.org/10.3390/bios12050333 - 13 May 2022
Viewed by 582
Abstract
Continuously monitoring transcutaneous CO2 partial pressure is of crucial importance in the diagnosis and treatment of respiratory and cardiac diseases. Despite significant progress in the development of CO2 sensors, their implementation as portable or wearable devices for real-time monitoring remains under-explored. [...] Read more.
Continuously monitoring transcutaneous CO2 partial pressure is of crucial importance in the diagnosis and treatment of respiratory and cardiac diseases. Despite significant progress in the development of CO2 sensors, their implementation as portable or wearable devices for real-time monitoring remains under-explored. Here, we report on the creation of a wearable prototype device for transcutaneous CO2 monitoring based on quantifying the fluorescence of a highly breathable CO2-sensing film. The developed materials are based on a fluorescent pH indicator (8-hydroxy-1,3,6-pyrenetrisulfonic acid trisodium salt or HPTS) embedded into hydrophobic polymer matrices. The film’s fluorescence is highly sensitive to changes in CO2 partial pressure in the physiological range, as well as photostable and insensitive to humidity. The device and medical-grade films are based on our prior work on transcutaneous oxygen-sensing technology, which has been extensively validated clinically. Full article
(This article belongs to the Special Issue Frontiers of Wearable Biosensors for Human Health Monitoring)
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Communication
Two-Dimensional Ti3C2 MXene-Based Novel Nanocomposites for Breath Sensors for Early Detection of Diabetes Mellitus
Biosensors 2022, 12(5), 332; https://doi.org/10.3390/bios12050332 - 13 May 2022
Viewed by 768
Abstract
The rates of diabetes throughout the world are rising rapidly, impacting nearly every country. New research is focused on better ways to monitor and treat this disease. Breath acetone levels have been defined as a biomarker for diabetes. The development of a method [...] Read more.
The rates of diabetes throughout the world are rising rapidly, impacting nearly every country. New research is focused on better ways to monitor and treat this disease. Breath acetone levels have been defined as a biomarker for diabetes. The development of a method to monitor and diagnose diabetes utilizing breath acetone levels would provide a fast, easy, and non-invasive treatment option. An ideal material for point-of-care diabetes management would need to have a high response to acetone, high acetone selectivity, low interference from humidity, and be able to operate at room temperature. Chemiresistive gas sensors are a promising method for sensing breath acetone due to their simple fabrication and easy operation. Certain semiconductor materials in chemiresistive sensors can react to acetone in the air and produce changes in resistance that can be correlated with acetone levels. While these materials have been developed and show strong responses to acetone with good selectivity, most of them must operate at high temperatures (compared to RT), causing high power consumption, unstable device operation, and complex device design. In this paper, we systematically studied a series of 2-dimensional MXene-based nanocomposites as the sensing materials in chemiresistive sensors to detect 2.86 ppm of acetone at room temperature. Most of them showed great sensitivity and selectivity for acetone. In particular, the 1D/2D CrWO/Ti3C2 nanocomposite showed the best sensing response to acetone: nine times higher sensitivity than 1D KWO nanowires. To determine the sensing selectivity, a CrWO/Ti3C2 nanocomposite-based sensor was exposed to various common vapors in human breath. The result revealed that it has excellent selectivity for acetone, and far lower responses to other vapors. All these preliminary results indicate that this material is a promising candidate for the creation of a point-of-care diabetes management device. Full article
(This article belongs to the Special Issue Nanomaterials and Nanostructure Devices for Biosensing)
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Article
Electrochemical Biosensor Using Nitrogen-Doped Graphene/Au Nanoparticles/DNAzyme for Ca2+ Determination
Biosensors 2022, 12(5), 331; https://doi.org/10.3390/bios12050331 - 12 May 2022
Viewed by 657
Abstract
An electrochemical biosensor for detecting Ca2+ concentration was proposed using glass carbon electrodes (GCEs) modified with nitrogen-doped graphene (NGR), gold nanoparticles (AuNPs) and DNAzyme. The resistance signal was amplified through two methods: electrochemical reduction of AuNPs on the NGR surface to increase [...] Read more.
An electrochemical biosensor for detecting Ca2+ concentration was proposed using glass carbon electrodes (GCEs) modified with nitrogen-doped graphene (NGR), gold nanoparticles (AuNPs) and DNAzyme. The resistance signal was amplified through two methods: electrochemical reduction of AuNPs on the NGR surface to increase the specific surface area of the electrode and strengthen the adsorption of DNAzyme; and increasement of the DNAzyme base sequence. The process of electrode modification was characterized by scanning electron microscopy, Raman spectroscopy, cyclic voltammetry (CV), and electrochemical impedance spectroscopy (EIS). Experimental parameters’ influence, such as the deposition time of gold nanoparticles and the detection time, were assessed by electrochemical methods. The linear ranges of the electrochemical biosensor were in the range from 5 × 10−6 to 5 × 10−5 and 5 × 10−5 to 4 × 10−4 M, with a detection limit of 3.8 × 10−6 M. The concentration of Ca2+ in the serum of dairy cows was determined by the biosensor with satisfactory results, which could be potentially used to diagnose subclinical hypocalcemia. Full article
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Article
A Digital Microfluidic Device Integrated with Electrochemical Impedance Spectroscopy for Cell-Based Immunoassay
Biosensors 2022, 12(5), 330; https://doi.org/10.3390/bios12050330 - 12 May 2022
Viewed by 593
Abstract
The dynamic immune response to various diseases and therapies has been considered a promising indicator of disease status and therapeutic effectiveness. For instance, the human peripheral blood mononuclear cell (PBMC), as a major player in the immune system, is an important index to [...] Read more.
The dynamic immune response to various diseases and therapies has been considered a promising indicator of disease status and therapeutic effectiveness. For instance, the human peripheral blood mononuclear cell (PBMC), as a major player in the immune system, is an important index to indicate a patient’s immune function. Therefore, establishing a simple yet sensitive tool that can frequently assess the immune system during the course of disease and treatment is of great importance. This study introduced an integrated system that includes an electrochemical impedance spectroscope (EIS)-based biosensor in a digital microfluidic (DMF) device, to quantify the PBMC abundance with minimally trained hands. Moreover, we exploited the unique droplet manipulation feature of the DMF platform and conducted a dynamic cell capture assay, which enhanced the detection signal by 2.4-fold. This integrated system was able to detect as few as 104 PBMCs per mL, presenting suitable sensitivity to quantify PBMCs. This integrated system is easy-to-operate and sensitive, and therefore holds great potential as a powerful tool to profile immune-mediated therapeutic responses in a timely manner, which can be further evolved as a point-of-care diagnostic device to conduct near-patient tests from blood samples. Full article
(This article belongs to the Special Issue Immunosensors - Trends and Perspective)
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