Biosensors

13 pages, 1648 KiB

Open AccessArticle

Biomimetic Plant-Root-Inspired Robotic Sensor System

by Margarita Alvira, Alessio Mondini, Gian Luigi Puleo, Islam Bogachan Tahirbegi, Lucia Beccai, Ali Sadeghi, Barbara Mazzolai, Mònica Mir and Josep Samitier

Biosensors 2024, 14(12), 565; https://doi.org/10.3390/bios14120565 - 22 Nov 2024

Abstract

There are many examples in nature in which the ability to detect is combined with decision-making, such as the basic survival instinct of plants and animals to search for food. We can technically translate this innate function via the use of robotics with [...] Read more.

There are many examples in nature in which the ability to detect is combined with decision-making, such as the basic survival instinct of plants and animals to search for food. We can technically translate this innate function via the use of robotics with integrated sensors and artificial intelligence. However, the integration of sensing capabilities into robotics has traditionally been neglected due to the significant associated technical challenges. Inspired by plant-root chemotropism, we present a miniaturized electrochemical array integrated into a robotic tip, embedding a customized micro-potentiometer. The system contains solid-state sensors fitted to the tip of the robotic root to three-dimensionally monitor potassium and pH changes in a moist, soil-like environment, providing an integrated electronic readout. The sensors measure a range of parameters compatible with realistic soil conditions. The sensors’ response can trigger the movement of the robotic root with a control algorithm inspired by the behavior of the plant root that determines the optimal path toward root growth, simulating the decision-making process of a plant. This nature-inspired technology may lead, in the future, to the realization of robotic devices with the potential for monitoring and exploring the soil autonomously. Full article

(This article belongs to the Special Issue Electrochemical (Bio)Sensors as Promising Analytical Tools in the Analysis of Soils, Plants and Environmental Monitoring)

► Show Figures

Figure 1

37 pages, 6074 KiB

Open AccessReview

Advances in Surface-Enhanced Raman Spectroscopy for Urinary Metabolite Analysis: Exploiting Noble Metal Nanohybrids

by Ningbin Zhao, Peizheng Shi, Zengxian Wang, Zhuang Sun, Kaiqiang Sun, Chen Ye, Li Fu and Cheng-Te Lin

Biosensors 2024, 14(12), 564; https://doi.org/10.3390/bios14120564 - 21 Nov 2024

Abstract

This review examines recent advances in surface-enhanced Raman spectroscopy (SERS) for urinary metabolite analysis, focusing on the development and application of noble metal nanohybrids. We explore the diverse range of hybrid materials, including carbon-based, metal–organic-framework (MOF), silicon-based, semiconductor, and polymer-based systems, which have [...] Read more.

This review examines recent advances in surface-enhanced Raman spectroscopy (SERS) for urinary metabolite analysis, focusing on the development and application of noble metal nanohybrids. We explore the diverse range of hybrid materials, including carbon-based, metal–organic-framework (MOF), silicon-based, semiconductor, and polymer-based systems, which have significantly improved SERS performance for detecting key urinary biomarkers. The principles underlying SERS enhancement in these nanohybrids are discussed, elucidating both electromagnetic and chemical enhancement mechanisms. We analyze various fabrication methods that enable precise control over nanostructure morphology, composition, and surface chemistry. The review critically evaluates the analytical performance of different hybrid systems for detecting specific urinary metabolites, considering factors such as sensitivity, selectivity, and stability. We address the analytical challenges associated with SERS-based urinary metabolite analysis, including sample preparation, matrix effects, and data interpretation. Innovative solutions, such as the integration of SERS with microfluidic devices and the application of machine learning algorithms for spectral analysis, are highlighted. The potential of these advanced SERS platforms for point-of-care diagnostics and personalized medicine is discussed, along with future perspectives on wearable SERS sensors and multi-modal analysis techniques. This comprehensive overview provides insights into the current state and future directions of SERS technology for urinary metabolite detection, emphasizing its potential to revolutionize non-invasive health monitoring and disease diagnosis. Full article

(This article belongs to the Special Issue Feature Paper in Biosensor and Bioelectronic Devices 2024)

12 pages, 1275 KiB

Open AccessArticle

Choline Oxidase-Incorporated ATRP-Based Cerium Nanogels as Nanozymes for Colorimetric Detection of Hydrogen Peroxide and Choline

by Trung Hieu Vu, Byung Jo Yu and Moon Il Kim

Biosensors 2024, 14(12), 563; https://doi.org/10.3390/bios14120563 - 21 Nov 2024

Abstract

Choline is an important molecule in monitoring food safety and infant nutrition. Here, we report Ce nanogels synthesized by atom transfer radical polymerization (ATRP) employing Ce-coordinated acryloyl-lysine polymer brushes (Ce@SiO₂ NGs) as highly efficient cascade nanozymes for colorimetric detection of choline. The [...] Read more.

Choline is an important molecule in monitoring food safety and infant nutrition. Here, we report Ce nanogels synthesized by atom transfer radical polymerization (ATRP) employing Ce-coordinated acryloyl-lysine polymer brushes (Ce@SiO₂ NGs) as highly efficient cascade nanozymes for colorimetric detection of choline. The synthesized Ce@SiO₂ NGs demonstrated remarkable peroxidase-like activity with a porous exterior, which are essential to entrap choline oxidase (COx) to yield COx@Ce@SiO₂ NGs and construct a cascade reaction system to detect choline. Immobilized COx catalyzed the oxidation of choline in food samples to produce H₂O₂, which subsequently induced the oxidation of chromogenic substrate 3,3′,5,5′-tetramethylbenzidine (TMB) to produce blue color signals. This method enabled the selective and sensitive detection of target choline with a satisfactory linear range of 4–400 μM, which is sufficient to analyze foodborne choline. The practical utility of the COx@Ce@SiO₂ NG-based assay was successfully validated to determine choline spiked in commercially available milk and infant formula with high accuracy and precision values. This approach provides a simple and affordable method of choline detection and has the potential to lead to more developments in ATRP-based nanozymes for diverse biosensing applications. Full article

(This article belongs to the Special Issue Feature Paper in Biosensor and Bioelectronic Devices 2024)

► Show Figures

Figure 1

19 pages, 3996 KiB

Open AccessArticle

Peroxidase-like Nanoparticles of Noble Metals Stimulate Increasing Sensitivity of Flavocytochrome b₂-Based L-Lactate Biosensors

by Galina Gayda, Olha Demkiv, Nataliya Stasyuk, Yuriy Boretsky, Mykhailo Gonchar and Marina Nisnevitch

Biosensors 2024, 14(11), 562; https://doi.org/10.3390/bios14110562 - 20 Nov 2024

Abstract

We report the development of amperometric biosensors (ABSs) employing flavocytochrome b₂ (Fcb₂) coupled with nanoparticles (NPs) of noble metals on graphite electrode (GE) surfaces. Each NPs/GE configuration was evaluated for its ability to decompose hydrogen peroxide (H₂O [...] Read more.

We report the development of amperometric biosensors (ABSs) employing flavocytochrome b₂ (Fcb₂) coupled with nanoparticles (NPs) of noble metals on graphite electrode (GE) surfaces. Each NPs/GE configuration was evaluated for its ability to decompose hydrogen peroxide (H₂O₂), mimicking peroxidase (PO) activity. The most effective nanoPO (nPO) was selected for developing ABSs targeting L-lactate. Consequently, several Fcb₂/nPO-based ABSs with enhanced sensitivity to L-lactate were developed, demonstrating mediated ET between Fcb₂ and the GE surface. The positive effect of noble metal NPs on Fcb₂-based sensor sensitivity may be explained by the synergy between their dual roles as both PO mimetics and electron transfer mediators. Furthermore, our findings provide preliminary data that may prompt a re-evaluation of the mechanism of L-lactate oxidation in Fcb₂-mediated catalysis. Previously, it was believed that L-lactate oxidation via Fcb₂ catalysis did not produce H₂O₂, unlike catalysis via L-lactate oxidase. Our initial research revealed that the inclusion of nPO in Fcb₂-based ABSs significantly increased their sensitivity. Employing other PO mimetics in ABSs for L-lactate yielded similar results, reinforcing our hypothesis that trace amounts of H₂O₂ may be generated as a transient intermediate in this reaction. The presence of nPO enhances the L-lactate oxidation rate through H₂O₂ utilization, leading to signal amplification and heightened bioelectrode sensitivity. The proposed ABSs have been successfully tested on blood serum and fermented food samples, showing their promise for L-lactate monitoring in medicine and the food industry. Full article

(This article belongs to the Special Issue Microelectrode Array for Biomedical Applications)

► Show Figures

Figure 1

27 pages, 8324 KiB

Open AccessReview

Recent Advances in the Fabrication and Application of Electrochemical Paper-Based Analytical Devices

by Zarfashan Shahid, Kornautchaya Veenuttranon, Xianbo Lu and Jiping Chen

Biosensors 2024, 14(11), 561; https://doi.org/10.3390/bios14110561 - 20 Nov 2024

Abstract

In response to growing environmental concerns, the scientific community is increasingly incorporating green chemistry principles into modern analytical techniques. Electrochemical paper-based analytical devices (ePADs) have emerged as a sustainable and efficient alternative to conventional analytical devices, offering robust applications in point-of-care testing, personalized [...] Read more.

In response to growing environmental concerns, the scientific community is increasingly incorporating green chemistry principles into modern analytical techniques. Electrochemical paper-based analytical devices (ePADs) have emerged as a sustainable and efficient alternative to conventional analytical devices, offering robust applications in point-of-care testing, personalized healthcare, environmental monitoring, and food safety. ePADs align with green chemistry by minimizing reagent use, reducing energy consumption, and being disposable, making them ideal for eco-friendly and cost-effective analyses. Their user-friendly interface, alongside sensitive and selective detection capabilities, has driven their popularity in recent years. This review traces the evolution of ePADs from simple designs to complex multilayered structures that optimize analyte flow and improve detection. It also delves into innovative electrode fabrication methods, assessing key advantages, limitations, and modification strategies for enhanced sensitivity. Application-focused sections explore recent advancements in using ePADs for detecting diseases, monitoring environmental hazards like heavy metals and bacterial contamination, and screening contaminants in food. The integration of cutting-edge technologies, such as wearable wireless devices and the Internet of Things (IoT), further positions ePADs at the forefront of point-of-care testing (POCT). Finally, the review identifies key research gaps and proposes future directions for the field. Full article

(This article belongs to the Special Issue Paper-Based Biosensing Technologies: From Design to Application)

► Show Figures

Figure 1

29 pages, 4599 KiB

Open AccessReview

Advances in Wearable Biosensors for Healthcare: Current Trends, Applications, and Future Perspectives

by Dang-Khoa Vo and Kieu The Loan Trinh

Biosensors 2024, 14(11), 560; https://doi.org/10.3390/bios14110560 - 18 Nov 2024

Abstract

Wearable biosensors are a fast-evolving topic at the intersection of healthcare, technology, and personalized medicine. These sensors, which are frequently integrated into clothes and accessories or directly applied to the skin, provide continuous, real-time monitoring of physiological and biochemical parameters such as heart [...] Read more.

Wearable biosensors are a fast-evolving topic at the intersection of healthcare, technology, and personalized medicine. These sensors, which are frequently integrated into clothes and accessories or directly applied to the skin, provide continuous, real-time monitoring of physiological and biochemical parameters such as heart rate, glucose levels, and hydration status. Recent breakthroughs in downsizing, materials science, and wireless communication have greatly improved the functionality, comfort, and accessibility of wearable biosensors. This review examines the present status of wearable biosensor technology, with an emphasis on advances in sensor design, fabrication techniques, and data analysis algorithms. We analyze diverse applications in clinical diagnostics, chronic illness management, and fitness tracking, emphasizing their capacity to transform health monitoring and facilitate early disease diagnosis. Additionally, this review seeks to shed light on the future of wearable biosensors in healthcare and wellness by summarizing existing trends and new advancements. Full article

(This article belongs to the Special Issue Artificial Skins and Wearable Biosensors for Healthcare Monitoring)

► Show Figures

Figure 1

16 pages, 2696 KiB

Open AccessArticle

A Paper-Based Assay for the Determination of Total Antioxidant Capacity in Human Serum Samples

by Michelle T. Tran, Sophia V. Gomez, Vera Alenicheva and Vincent T. Remcho

Biosensors 2024, 14(11), 559; https://doi.org/10.3390/bios14110559 - 18 Nov 2024

Abstract

Determining the total antioxidant capacity (TAC) of biological samples is a valuable approach to measuring health status under oxidative stress conditions, such as infertility and type 2 diabetes. The Trolox equivalent antioxidant capacity (TEAC) assay is the most common approach to evaluating TAC [...] Read more.

Determining the total antioxidant capacity (TAC) of biological samples is a valuable approach to measuring health status under oxidative stress conditions, such as infertility and type 2 diabetes. The Trolox equivalent antioxidant capacity (TEAC) assay is the most common approach to evaluating TAC in biological matrices. This assay is typically performed in clinical settings on a microtiter plate using a plate reader. However, the instrumentation and expertise requirements, and the resulting delay in the reporting of assay outcomes, make solution-based TEAC assays impractical for point-of-care or at-home testing, where individuals may want to monitor their health status during treatment. This work introduces the first microfluidic paper-based analytical device (µPAD) that measures TAC in human serum using TEAC assay chemistry. TAC was determined through a colorimetric image analysis of the degree of decolorization of 2,2′-azinobis(3-ethylbenzothiazoline-6-sulfonic acid) radical cations (ABTS^●+) by serum antioxidants. The µPAD showed a linear response to Trolox, ranging from 0.44 to 2.4 mM, (r = 0.999). The performance of paper-based TEAC assays was validated through direct comparison to solution-based TEAC assays. There was a 0.04 mM difference in TAC values between the two platforms, well within one standard deviation of a standard solution-based assay conducted on an aliquot of the same serum sample (±0.25 mM). The µPAD had a limit of detection (LOD) of 0.20 mM, well below the TAC of normal human serum. The results suggest that the proposed device can be used for biological TAC determination and expands the field of TAC analysis in point-of-care health monitoring. Full article

(This article belongs to the Section Nano- and Micro-Technologies in Biosensors)

► Show Figures

Graphical abstract

21 pages, 13351 KiB

Open AccessArticle

Bioluminescent Whole-Cell Bioreporter Bacterial Panel for Sustainable Screening and Discovery of Bioactive Compounds Derived from Mushrooms

by Calin Trif, Jovana Vunduk, Yardnapar Parcharoen, Aporn Bualuang and Robert S. Marks

Biosensors 2024, 14(11), 558; https://doi.org/10.3390/bios14110558 - 17 Nov 2024

Abstract

This study presents a rapid and comprehensive method for screening mushroom extracts for the putative discovery of bioactive molecules, including those exhibiting antimicrobial activity. This approach utilizes a panel of bioluminescent bacteria, whose light production is a sensitive indicator of various cellular effects [...] Read more.

This study presents a rapid and comprehensive method for screening mushroom extracts for the putative discovery of bioactive molecules, including those exhibiting antimicrobial activity. This approach utilizes a panel of bioluminescent bacteria, whose light production is a sensitive indicator of various cellular effects triggered by the extracts, including disruption of bacterial communication (quorum sensing), protein and DNA damage, fatty acid metabolism alterations, and oxidative stress induction. The bioassay’s strength is its ability to efficiently analyze a large number of extracts simultaneously while also assessing several different mechanisms of toxicity, significantly reducing screening time. All samples analyzed exhibited more than one cellular effect, as indicated by the reporter bacteria. Four samples (C. cornucopioides, F. fomentarius, I. obliquus, and M. giganteus) displayed the highest number (six) of possible mechanisms of antibacterial activity. Additionally, combining extraction and purification protocols with a bioluminescent bacterial panel enables simultaneous improvement of the desired antimicrobial properties of the extracts. The presented approach offers a valuable tool for uncovering the diverse antimicrobial mechanisms of mushroom extracts. Full article

(This article belongs to the Special Issue Prof. Shishmon Belkin 30th Anniversary of Working in Bioluminescent Bioreporter Bacteria Biosensors)

► Show Figures

Figure 1

20 pages, 7800 KiB

Open AccessArticle

Portable Miniaturized IoT-Enabled Point-of-Care Device for Electrochemical Sensing of Zopiclone in Cocktails

by María Gabriela Mejía-Méndez, Paula C. Cifuentes-Delgado, Sergio D. Gómez, Crhistian C. Segura, Nancy Ornelas-Soto and Johann F. Osma

Biosensors 2024, 14(11), 557; https://doi.org/10.3390/bios14110557 - 16 Nov 2024

Abstract

This study proposes a portable and IoT-based electrochemical point-of-care sensing device for detecting zopiclone in cocktails. The system utilizes an electrochemical laccase biosensor and a potentiostat, offering a low-cost and portable device for detecting this sedative drug in cocktails. The sensor characterization experiments [...] Read more.

This study proposes a portable and IoT-based electrochemical point-of-care sensing device for detecting zopiclone in cocktails. The system utilizes an electrochemical laccase biosensor and a potentiostat, offering a low-cost and portable device for detecting this sedative drug in cocktails. The sensor characterization experiments demonstrated the linear behavior of the oxidation and reduction currents for each of the targeted concentrations of zopiclone, enabling their detection and quantification even when mixed with an interfering substance. The proposed system could be used for the in situ analysis of cocktails, providing a valuable tool for monitoring the presence of hypnotic drugs in various social and clinical settings. The study utilized materials and reagents, including zopiclone, lab-made lemon juice, lab-made tequila, and lab-made triple sec, all prepared with reactants obtained in Bogotá, Colombia. The potentiostat used in the system was designed to manage cyclic voltammetry measurements. The electrochemical cells’ durability and longevity were also tested and characterized, with all electrodes undergoing 200 tests and their performance degradation varying according to the molecule used. The study concludes that the proposed system offers a valuable tool for detecting and monitoring pharmaceutical substances in various interfering ingredients that build up cocktails. Further research and application of this system can help address the global concern surrounding the administration of hypnotic substances to unknowing consumers through food or drinks to enable robbery and sexual assault. Full article

(This article belongs to the Special Issue Electrochemical Biosensing Platforms for Food, Drug and Health Safety)

► Show Figures

Figure 1

34 pages, 3181 KiB

Open AccessReview

Commercial Wearables for the Management of People with Autism Spectrum Disorder: A Review

by Jonathan Hernández-Capistrán, Giner Alor-Hernández, Humberto Marín-Vega, Maritza Bustos-López, Laura Nely Sanchez-Morales and Jose Luis Sanchez-Cervantes

Biosensors 2024, 14(11), 556; https://doi.org/10.3390/bios14110556 - 15 Nov 2024

Abstract

Autism Spectrum Disorder (ASD) necessitates comprehensive management, addressing complex challenges in social communication, behavioral regulation, and sensory processing, for which wearable technologies offer valuable tools to monitor and support interventions. Therefore, this review explores recent advancements in wearable technology, categorizing devices based on [...] Read more.

Autism Spectrum Disorder (ASD) necessitates comprehensive management, addressing complex challenges in social communication, behavioral regulation, and sensory processing, for which wearable technologies offer valuable tools to monitor and support interventions. Therefore, this review explores recent advancements in wearable technology, categorizing devices based on executive function, psychomotor skills, and the behavioral/emotional/sensory domain, highlighting their potential to improve ongoing management and intervention. To ensure rigor and comprehensiveness, the review employs a PRISMA-based methodology. Specifically, literature searches were conducted across diverse databases, focusing on studies published between 2014 and 2024, to identify the most commonly used wearables in ASD research. Notably, 55.45% of the 110 devices analyzed had an undefined FDA status, 23.6% received 510(k) clearance, and only a small percentage were classified as FDA Breakthrough Devices or in the submission process. Additionally, approximately 50% of the devices utilized sensors like ECG, EEG, PPG, and EMG, highlighting their widespread use in real-time physiological monitoring. Our work comprehensively analyzes a wide array of wearable technologies, including emerging and advanced. While these technologies have the potential to transform ASD management through real-time data collection and personalized interventions, improved clinical validation and user-centered design are essential for maximizing their effectiveness and user acceptance. Full article

(This article belongs to the Special Issue Recent Advances in Wearable Biosensors for Human Health Monitoring)

► Show Figures

Figure 1

14 pages, 2350 KiB

Open AccessArticle

Ultra-Selective and Sensitive Fluorescent Chemosensor Based on Phage Display-Derived Peptide with an N-Terminal Cu(II)-Binding Motif

by Marta Sosnowska, Tomasz Łęga, Dawid Nidzworski, Marcin Olszewski and Beata Gromadzka

Biosensors 2024, 14(11), 555; https://doi.org/10.3390/bios14110555 - 14 Nov 2024

Abstract

Copper, along with gold, was among the first metals that humans employed. Thus, the copper pollution of the world’s water resources is escalating, posing a significant threat to human health and aquatic ecosystems. It is crucial to develop detection technology that is both [...] Read more.

Copper, along with gold, was among the first metals that humans employed. Thus, the copper pollution of the world’s water resources is escalating, posing a significant threat to human health and aquatic ecosystems. It is crucial to develop detection technology that is both low-cost and feasible, as well as ultra-selective and sensitive. This study explored the use of the NH₂-Xxx-His motif-derived peptide from phage display technology for ultra-selective Cu²⁺ detection. Various Cu-binding M13 phage clones were isolated, and their affinity and cross-reactivity for different metal ions were determined. A detailed analysis of the amino acid sequence of the unique Cu-binding peptides was employed. For the development of an optical chemosensor, a peptide with an NH₂-Xxx-His motif was selected. The dansyl group was incorporated during solid-phase peptide synthesis, and fluorescence detection assays were employed. The efficacy of the Cu²⁺-binding peptide was verified through spectroscopic measurements. In summary, we developed a highly selective and sensitive fluorescent chemosensor for Cu²⁺ detection based on a peptide sequence from a phage display library that carries the N-terminal Xxx-His motif. Full article

(This article belongs to the Special Issue Application of Biosensors in Environmental Monitoring)

► Show Figures

Figure 1

19 pages, 9106 KiB

Open AccessReview

Chemical Heating for Minimally Instrumented Point-of-Care (POC) Molecular Diagnostics

by Michael G. Mauk, Felix Ansah and Mohamed El-Tholoth

Biosensors 2024, 14(11), 554; https://doi.org/10.3390/bios14110554 - 13 Nov 2024

Abstract

The minimal instrumentation of portable medical diagnostic devices for point-of-care applications is facilitated by using chemical heating in place of temperature-regulated electrical heaters. The main applications are for isothermal nucleic acid amplification tests (NAATs) and other enzymatic assays that require elevated, controlled temperatures. [...] Read more.

The minimal instrumentation of portable medical diagnostic devices for point-of-care applications is facilitated by using chemical heating in place of temperature-regulated electrical heaters. The main applications are for isothermal nucleic acid amplification tests (NAATs) and other enzymatic assays that require elevated, controlled temperatures. In the most common implementation, heat is generated by the exothermic reaction of a metal (e.g., magnesium, calcium, or lithium) with water or air, buffered by a phase-change material that maintains a near-constant temperature to heat the assay reactions. The ability to incubate NAATs electricity-free and to further to detect amplification with minimal instrumentation opens the door for fully disposable, inexpensive molecular diagnostic devices that can be used for pathogen detection as needed in resource-limited areas and during natural disasters, wars, and civil disturbances when access to electricity may be interrupted. Several design approaches are reviewed, including more elaborate schemes for multiple stages of incubation at different temperatures. Full article

(This article belongs to the Special Issue Biosensors Based on Isothermal Nucleic Acid Amplification Strategies)

► Show Figures

Figure 1

19 pages, 5570 KiB

Open AccessArticle

Hybrid Functional Near-Infrared Spectroscopy System and Electromyography for Prosthetic Knee Control

by Nouf Jubran AlQahtani, Ibraheem Al-Naib, Ijlal Shahrukh Ateeq and Murad Althobaiti

Biosensors 2024, 14(11), 553; https://doi.org/10.3390/bios14110553 - 13 Nov 2024

Abstract

The increasing number of individuals with limb loss worldwide highlights the need for advancements in prosthetic knee technology. To improve control and quality of life, integrating brain–computer communication with motor imagery offers a promising solution. This study introduces a hybrid system that combines [...] Read more.

The increasing number of individuals with limb loss worldwide highlights the need for advancements in prosthetic knee technology. To improve control and quality of life, integrating brain–computer communication with motor imagery offers a promising solution. This study introduces a hybrid system that combines electromyography (EMG) and functional near-infrared spectroscopy (fNIRS) to address these limitations and enhance the control of knee movements for individuals with above-knee amputations. The study involved an experiment with nine healthy male participants, consisting of two sessions: real execution and imagined execution using motor imagery. The OpenBCI Cyton board collected EMG signals corresponding to the desired movements, while fNIRS monitored brain activity in the prefrontal and motor cortices. The analysis of the simultaneous measurement of the muscular and hemodynamic responses demonstrated that combining these data sources significantly improved the classification accuracy compared to using each dataset alone. The results showed that integrating both the EMG and fNIRS data consistently achieved a higher classification accuracy. More specifically, the Support Vector Machine performed the best during the motor imagery tasks, with an average accuracy of 49.61%, while the Linear Discriminant Analysis excelled in the real execution tasks, achieving an average accuracy of 89.67%. This research validates the feasibility of using a hybrid approach with EMG and fNIRS to enable prosthetic knee control through motor imagery, representing a significant advancement potential in prosthetic technology. Full article

(This article belongs to the Section Wearable Biosensors)

► Show Figures

Figure 1

29 pages, 4900 KiB

Open AccessArticle

Physicochemical Rationale of Matrix Effects Involved in the Response of Hydrogel-Embedded Luminescent Metal Biosensors

by Elise Rotureau, Christophe Pagnout and Jérôme F. L. Duval

Biosensors 2024, 14(11), 552; https://doi.org/10.3390/bios14110552 - 13 Nov 2024

Abstract

There is currently a critical need for understanding how the response and activity of whole-cell bacterial reporters positioned in a complex biological or environmental matrix are impacted by the physicochemical properties of their micro-environment. Accordingly, a comprehensive analysis of the bioluminescence response of [...] Read more.

There is currently a critical need for understanding how the response and activity of whole-cell bacterial reporters positioned in a complex biological or environmental matrix are impacted by the physicochemical properties of their micro-environment. Accordingly, a comprehensive analysis of the bioluminescence response of Cd(II)-inducible PzntA-luxCDABE Escherichia coli biosensors embedded in silica-based hydrogels is reported to decipher how metal bioavailability, cell photoactivity and ensuing light bioproduction are impacted by the hydrogel environment and the associated matrix effects. The analysis includes the account of (i) Cd speciation and accumulation in the host hydrogels, in connection with their reactivity and electrostatic properties, and (ii) the reduced bioavailability of resources for the biosensors confined (deep) inside the hydrogels. The measurements of the bioluminescence response of the Cd(II) inducible-lux biosensors in both hydrogels and free-floating cell suspensions are completed by those of the constitutive rrnB P1-luxCDABE E. coli so as to probe cell metabolic activity in these two situations. The approach contributes to unraveling the connections between the electrostatic hydrogel charge, the nutrient/metal bioavailabilities and the resulting Cd-triggered bioluminescence output. Biosensors are hosted in hydrogels with thickness varying between 0 mm (the free-floating cell situation) and 1.6 mm, and are exposed to total Cd concentrations from 0 to 400 nM. The partitioning of bioavailable metals at the hydrogel/solution interface following intertwined metal speciation, diffusion and Boltzmann electrostatic accumulation is addressed by stripping chronopotentiometry. In turn, we detail how the bioluminescence maxima generated by the Cd-responsive cells under all tested Cd concentration and hydrogel thickness conditions collapse remarkably well on a single plot featuring the dependence of bioluminescence on free Cd concentration at the individual cell level. Overall, the construction of this master curve integrates the contributions of key and often overlooked processes that govern the bioavailability properties of metals in 3D matrices. Accordingly, the work opens perspectives for quantitative and mechanistic monitoring of metals by biosensors in environmental systems like biofilms or sediments. Full article

(This article belongs to the Section Environmental Biosensors and Biosensing)

► Show Figures

Graphical abstract

15 pages, 1885 KiB

Open AccessArticle

Innovative Peptide-Based Plasmonic Optical Biosensor for the Determination of Cholesterol

by Ana Lia Bernardo, Anne Parra, Virginia Cebrián, Óscar Ahumada, Sergio Oddi and Enrico Dainese

Biosensors 2024, 14(11), 551; https://doi.org/10.3390/bios14110551 - 13 Nov 2024

Abstract

Plasmonic-based biosensors have gained prominence as potent optical biosensing platforms in both scientific and medical research, attributable to their enhanced sensitivity and precision in detecting biomolecular and chemical interactions. However, the detection of low molecular weight analytes with high sensitivity and specificity remains [...] Read more.

Plasmonic-based biosensors have gained prominence as potent optical biosensing platforms in both scientific and medical research, attributable to their enhanced sensitivity and precision in detecting biomolecular and chemical interactions. However, the detection of low molecular weight analytes with high sensitivity and specificity remains a complex and unresolved issue, posing significant limitations for the advancement of clinical diagnostic tools and medical device technologies. Notably, abnormal cholesterol levels are a well-established indicator of various pathological conditions; yet, the quantitative detection of the free form of cholesterol is complicated by its small molecular size, pronounced hydrophobicity, and the necessity for mediator molecules to achieve efficient sensing. In the present study, a novel strategy for cholesterol quantification was developed, leveraging a plasmonic optical readout in conjunction with a highly specific cholesterol-binding peptide (C-pept) as a biorecognition element, anchored on a functionalized silica substrate. The resulting biosensor exhibited an exceptionally low detection limit of 21.95 µM and demonstrated a linear response in the 10–200 µM range. This peptide-integrated plasmonic sensor introduces a novel one-step competitive method for cholesterol quantification, positioning itself as a highly sensitive biosensing modality for implementation within the AVAC platform, which operates using reflective dark-field microscopy. Full article

(This article belongs to the Special Issue Nanotechnology-Enabled Biosensors)

► Show Figures

Graphical abstract

12 pages, 6188 KiB

Open AccessArticle

Bi-Plane Multicolor Scanning Illumination Microscopy with Multispot Excitation and a Distorted Diffraction Grating

by Siwei Li, Yunke Zhang, Zhiwen Liao, Zengyuan Tian, Hairulazwan Hashim, Youjun Zeng and Yandong Zhang

Biosensors 2024, 14(11), 550; https://doi.org/10.3390/bios14110550 - 13 Nov 2024

Abstract

Multifocus microscopy has previously been demonstrated to provide volumetric information from a single shot. However, the practical application of this method is challenging due to its weak optical sectioning and limited spatial resolution. Here, we report on the combination of a distorted diffraction [...] Read more.

Multifocus microscopy has previously been demonstrated to provide volumetric information from a single shot. However, the practical application of this method is challenging due to its weak optical sectioning and limited spatial resolution. Here, we report on the combination of a distorted diffraction grating and multifocal scanning illumination microscopy to improve spatial resolution and contrast. DG is introduced in the emission path of the multifocal scanning illumination microscopy, which splits the fluorescence signal from different sample layers into different diffraction orders. After postprocessing, super-resolution wide-field images of different sample layers can be reconstructed from single 2D scanning. Full article

(This article belongs to the Special Issue Advanced Optical Methods for Biosensing)

► Show Figures

Figure 1

15 pages, 8475 KiB

Open AccessArticle

A Novel High-Throughput Sample-in-Result-Out Device for the Rapid Detection of Viral Nucleic Acids

by Fangning Wang, Fei Hu, Yunyun Zhang, Xichen Li, Qin Ma, Xincheng Wang and Niancai Peng

Biosensors 2024, 14(11), 549; https://doi.org/10.3390/bios14110549 - 13 Nov 2024

Abstract

Clustered regularly interspaced short palindromic repeats (CRISPR) molecular diagnostic technology is one of the most reliable diagnostic tools for infectious diseases due to its short reaction time, high sensitivity, and excellent specificity. However, compared with fluorescent polymerase chain reaction (PCR) technology, CRISPR molecular [...] Read more.

Clustered regularly interspaced short palindromic repeats (CRISPR) molecular diagnostic technology is one of the most reliable diagnostic tools for infectious diseases due to its short reaction time, high sensitivity, and excellent specificity. However, compared with fluorescent polymerase chain reaction (PCR) technology, CRISPR molecular diagnostic technology lacks high-throughput automated instrumentation and standardized detection reagents for high sensitivity, limiting its large-scale clinical application. In this study, a high-throughput automated device was developed by combining reagent lyophilization, extraction-free technology, and a one-pot consumable system. This innovative approach enabled the rapid sample-in-result-out detection of 48 samples in 25 min and demonstrated high sensitivity and specificity for the qualitative analysis of clinical samples. The obtained results show that the detection limit of the designed system for African swine fever virus (ASFV) is 0.5 copies/μL. As a proof concept, a single-tube dual-target nucleic acid detection method was developed, achieving a detection limit of 5 copies/μL for the ORF1ab and N genes of severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) within 45 min. The method is highly specific, reliable, and stable, providing a feasible solution for the clinical application of CRISPR nucleic acid detection technology. Full article

(This article belongs to the Special Issue Biosensing Technologies in Medical Diagnosis)

► Show Figures

Figure 1

16 pages, 7688 KiB

Open AccessArticle

Enhanced Detection of Vibrio harveyi Using a Dual-Composite DNAzyme-Based Biosensor

by Siying Li, Shuai Zhang, Weihong Jiang, Yuying Wang, Mingwang Liu, Mingsheng Lyu and Shujun Wang

Biosensors 2024, 14(11), 548; https://doi.org/10.3390/bios14110548 - 13 Nov 2024

Abstract

Vibrio harveyi is a serious bacterial pathogen which can infect a wide range of marine organisms, such as marine fish, invertebrates, and shrimp, in aquaculture, causing severe losses. In addition, V. harveyi can be transmitted through food and water, infecting humans and posing [...] Read more.

Vibrio harveyi is a serious bacterial pathogen which can infect a wide range of marine organisms, such as marine fish, invertebrates, and shrimp, in aquaculture, causing severe losses. In addition, V. harveyi can be transmitted through food and water, infecting humans and posing a serious threat to public safety. Therefore, rapid and accurate detection of this pathogen is key for the prevention and control of related diseases. In this study, nine rounds of in vitro screening were conducted with Systematic Evolution of Ligands by Exponential Enrichment (SELEX) technology using unmodified DNA libraries, targeting the crude extracellular matrix (CEM) of V. harveyi. Two DNAzymes, named DVh₁ and DVh₃, with high activity and specificity were obtained. Furthermore, a fluorescent biosensor with dual DNAzymes was constructed which exhibited improved detection efficiency. The sensor showed a good fluorescence response to multiple aquatic products (i.e., fish, shrimp, and shellfish) infected with V. harveyi, with a detection limit below 11 CFU/mL. The fluorescence signal was observed within 30 min of reaction after target addition. This simple, inexpensive, highly effective, and easy to operate DNAzymes biosensor can be used for field detection of V. harveyi. Full article

(This article belongs to the Section Optical and Photonic Biosensors)

► Show Figures

Graphical abstract

12 pages, 1852 KiB

Open AccessArticle

Development of an Escherichia coli Cell-Based Biosensor for Aspirin Monitoring by Genetic Engineering of MarR

by Yeonhong Kim, Yangwon Jeon, Kyeoungseok Song, Haekang Ji, Soon-Jin Hwang and Youngdae Yoon

Biosensors 2024, 14(11), 547; https://doi.org/10.3390/bios14110547 - 12 Nov 2024

Abstract

Multiple antibiotic resistance regulators (MarRs) control the transcription of genes in the mar operon of Escherichia coli in the presence of salicylic acid (SA). The interaction with SA induces conformational changes in the MarR released from the promoter of the mar operon, turning [...] Read more.

Multiple antibiotic resistance regulators (MarRs) control the transcription of genes in the mar operon of Escherichia coli in the presence of salicylic acid (SA). The interaction with SA induces conformational changes in the MarR released from the promoter of the mar operon, turning on transcription. We constructed an SA-specific E. coli cell-based biosensor by fusing the promoter of the mar operon (P_marO) and the gene that encodes an enhanced green fluorescent protein (egfp). Because SA and aspirin are structurally similar, a biosensor for monitoring aspirin can be obtained by genetically engineering MarR to be aspirin (ASP)-responsive. To shift the selectivity of MarR toward ASP, we changed the residues around the ligand-binding sites by site-directed mutagenesis. We examined the effects of genetic engineering on MarR by introducing MarRs with P_marO-egfp into E. coli. Among the tested mutants, MarR T72A improved the ASP responses by approximately 3 times compared to the wild-type MarR, while still showing an SA response. Although the MarR T72A biosensor exhibited mutual interference between SA and ASP, it accurately determined the ASP concentration in spiked water and medicine samples with over 90% accuracy. While the ASP biosensors still require improvement, our results provide valuable insights for developing E. coli cell-based biosensors for ASP and transcription factor-based biosensors in general. Full article

(This article belongs to the Special Issue Cell-Based Biosensors for Rapid Detection and Monitoring)

► Show Figures

Figure 1

Journal Description

Biosensors

Latest Articles

Journal Menu

Journal Browser

Highly Accessed Articles

Latest Books

E-Mail Alert

News

Topics

Conferences

Special Issues

Topical Collections

Further Information

Guidelines

MDPI Initiatives

Follow MDPI