Biosensors

16 pages, 4595 KiB

Open AccessArticle

A Novel Aggregation-Induced Emission-Based Electrochemiluminescence Aptamer Sensor Utilizing Red-Emissive Sulfur Quantum Dots for Rapid and Sensitive Malathion Detection

by Yajun Wu, Dongxiao Ma, Xiaoli Zhu and Fangquan Xia

Biosensors 2025, 15(1), 64; https://doi.org/10.3390/bios15010064 - 20 Jan 2025

Viewed by 630

Abstract

Rapid, effective, and cost-effective methods for large-scale screening of pesticide residues in the environment and agricultural products are important for assessing potential environmental risks and safeguarding human health. Here, we constructed a novel aggregation-induced emission (AIE) electrochemical aptamer (Apt) sensor based on red-emissive [...] Read more.

Rapid, effective, and cost-effective methods for large-scale screening of pesticide residues in the environment and agricultural products are important for assessing potential environmental risks and safeguarding human health. Here, we constructed a novel aggregation-induced emission (AIE) electrochemical aptamer (Apt) sensor based on red-emissive sulfur quantum dots (SQDs), which aimed at the rapid screening and quantitative detection of malathion. SQDs were prepared using a two-step oxidation method with good electrochemiluminescence (ECL) optical properties. These SQDs were modified onto the electrode surface to serve as ECL luminophores. Subsequently, Apt was introduced and modified to form a double-helix structure with the complementary chain (cDNA). The ECL signal was reduced because the biomolecules had poor electrical conductivity and inefficient electron transfer. When the target malathion was added, the double helix structure was unraveled, the malathion Apt fell off the electrode surface, and the ECL signal was restored. The linear range of detection was 1.0 × 10⁻¹³–1.0 × 10⁻⁸ mol·L⁻¹, and the detection limit was 0.219 fM. The successful preparation of the sensor not only develops the ECL optical properties of SQDs but also expands the application of SQDs in ECL sensing. Full article

(This article belongs to the Special Issue Advanced Electrochemical Biosensors and Their Applications)

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18 pages, 4136 KiB

Open AccessArticle

Sensitive Detection of Biomarker in Gingival Crevicular Fluid Based on Enhanced Electrochemiluminescence by Nanochannel-Confined Co₃O₄ Nanocatalyst

by Changfeng Zhu, Yujiao Zhao and Jiyang Liu

Biosensors 2025, 15(1), 63; https://doi.org/10.3390/bios15010063 - 19 Jan 2025

Viewed by 674

Abstract

The sensitive detection of inflammatory biomarkers in gingival crevicular fluid (GCF) is highly desirable for the evaluation of periodontal disease. Luminol-based electrochemiluminescence (ECL) immunosensors offer a promising approach for the fast and convenient detection of biomarkers. However, luminol’s low ECL efficiency under neutral [...] Read more.

The sensitive detection of inflammatory biomarkers in gingival crevicular fluid (GCF) is highly desirable for the evaluation of periodontal disease. Luminol-based electrochemiluminescence (ECL) immunosensors offer a promising approach for the fast and convenient detection of biomarkers. However, luminol’s low ECL efficiency under neutral conditions remains a challenge. This study developed an immunosensor by engineering an immunorecognition interface on the outer surface of mesoporous silica nanochannel film (SNF) and confining a Co₃O₄ nanocatalyst within the SNF nanochannels to improve the luminol ECL efficiency. The SNF was grown on an indium tin oxide (ITO) electrode using the simple Stöber solution growth method. A Co₃O₄ nanocatalyst was successfully confined within the SNF nanochannels through in situ electrodeposition, confirmed by X-ray photoelectron spectroscopy (XPS) and electrochemical measurements. The confined Co₃O₄ demonstrated excellent electrocatalytic activity, effectively enhancing luminol and H₂O₂ oxidation and boosting the ECL signal under neutral conditions. Using interleukin-6 (IL-6) as a proof-of-concept demonstration, the epoxy functionalization of the SNF outer surface enabled the covalent immobilization of capture antibodies, forming a specific immunorecognition interface. IL-6 binding induced immunocomplex formation, which reduced the ECL signal and allowed for quantitative detection. The immunosensor showed a linear detection range for IL-6 from 1 fg mL⁻¹ to 10 ng mL⁻¹, with a limit of detection (LOD) of 0.64 fg mL⁻¹. It also demonstrated good selectivity and anti-interference capabilities, enabling the successful detection of IL-6 in artificial GCF samples. Full article

(This article belongs to the Special Issue Biosensing and Diagnosis—2nd Edition)

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18 pages, 2000 KiB

Open AccessSystematic Review

Is Breath Best? A Systematic Review on the Accuracy and Utility of Nanotechnology Based Breath Analysis of Ketones in Type 1 Diabetes

by Kamal Marfatia, Jing Ni, Veronica Preda and Noushin Nasiri

Biosensors 2025, 15(1), 62; https://doi.org/10.3390/bios15010062 - 19 Jan 2025

Viewed by 709

Abstract

Timely ketone detection in patients with type 1 diabetes mellitus (T1DM) is critical for the effective management of diabetic ketoacidosis (DKA). This systematic review evaluates the current literature on breath-based analysis for ketone detection in T1DM, highlighting nanotechnology as a potential for a [...] Read more.

Timely ketone detection in patients with type 1 diabetes mellitus (T1DM) is critical for the effective management of diabetic ketoacidosis (DKA). This systematic review evaluates the current literature on breath-based analysis for ketone detection in T1DM, highlighting nanotechnology as a potential for a non-invasive alternative to blood-based ketone measurements. A comprehensive search across 5 databases identified 11 studies meeting inclusion criteria, showcasing various breath analysis techniques, such as semiconducting gas sensors, colorimetry, and nanoparticle-based chemo-resistive sensors. These studies report high sensitivity and correlation between breath acetone (BrAce) levels and blood ketones, with some demonstrating accuracies up to 94.7% and correlations reaching R² values as high as 0.98. However, significant heterogeneity in methodologies and cut-off values limits device comparability and precludes meta-analysis. Despite these challenges, the findings indicate that BrAce monitoring could offer significant clinical benefits by enabling the earlier detection of ketone buildup, reducing DKA-related hospitalisations and healthcare costs. Standardising BrAce measurement techniques and sensitivity thresholds is essential to broaden clinical adoption. This review underscores the promise of nanotechnology-based breath analysis as a transformative tool for DKA management, with potential utility across varied ketotic conditions. Full article

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

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22 pages, 7586 KiB

Open AccessReview

Potential of Zinc Oxide Nanostructures in Biosensor Application

by Ibrahim M. Maafa

Biosensors 2025, 15(1), 61; https://doi.org/10.3390/bios15010061 - 18 Jan 2025

Viewed by 502

Abstract

The burgeoning field of biosensors has seen significant advancements with the induction of zinc oxide (ZnO) nanostructures, because of their unique structural, electrical, and optical properties. ZnO nanostructures provide numerous benefits for biosensor applications. Their superior electron mobility enables effective electron transfer between [...] Read more.

The burgeoning field of biosensors has seen significant advancements with the induction of zinc oxide (ZnO) nanostructures, because of their unique structural, electrical, and optical properties. ZnO nanostructures provide numerous benefits for biosensor applications. Their superior electron mobility enables effective electron transfer between the bioreceptor and transducer, enhancing sensitivity and reducing detection limits. Furthermore, ZnO’s biocompatibility and non-toxicity make it ideal for in vivo applications, reducing the chances of adverse biological responses. This review paper explores the prospects of ZnO nanostructures in the development of biosensors, focusing on their morphological and structural characteristics. Various synthesis techniques, that include sol-gel, sputtering, and chemical vapor deposition, were successfully employed to prepare different ZnO nanostructures, like nanorods, nanotubes, and nanowires. The various findings in this field underscore the efficacy of ZnO nanostructures in enhancing the specificity and sensitivity of biosensors, presenting a promising avenue for the advancement of point-of-care diagnostic devices. Full article

(This article belongs to the Special Issue Nanomaterials for Biosensors)

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19 pages, 3676 KiB

Open AccessArticle

Electrochemical Determination of Doxorubicin in the Presence of Dacarbazine Using MWCNTs/ZnO Nanocomposite Modified Disposable Screen-Printed Electrode

by Somayeh Tajik, Hadi Beitollahi, Fariba Garkani Nejad and Zahra Dourandish

Biosensors 2025, 15(1), 60; https://doi.org/10.3390/bios15010060 - 17 Jan 2025

Viewed by 634

Abstract

In the current work, the MWCNTs/ZnO nanocomposite was successfully synthesized using simple method. Then, FE-SEM, XRD, and EDX techniques were applied for morphological and structural characterization. Afterward, a sensitive voltammetric sensor based on modification of a screen-printed carbon electrode (SPCE) using MWCNTs/ZnO nanocomposite [...] Read more.

In the current work, the MWCNTs/ZnO nanocomposite was successfully synthesized using simple method. Then, FE-SEM, XRD, and EDX techniques were applied for morphological and structural characterization. Afterward, a sensitive voltammetric sensor based on modification of a screen-printed carbon electrode (SPCE) using MWCNTs/ZnO nanocomposite was developed for the determination of doxorubicin in the presence of dacarbazine. To evaluate the electrochemical response of the MWCNTs/ZnO/SPCE towards doxorubicin, cyclic voltammetry (CV) was applied. The MWCNTs/ZnO nanocomposite showed a significant synergistic effect on the electrochemical response of the electrode for the redox reaction of doxorubicin. Also, the MWCNTs/ZnO/SPCE demonstrated an enhanced sensing platform for the quantification of doxorubicin, obtaining a detection limit (LOD) of 0.002 µM and a sensitivity of 0.0897 µA/µM, as determined by differential pulse voltammetry (DPV) within a linear range from 0.007 to 150.0 µM. Also, the MWCNTs/ZnO nanocomposite-modified SPCE showed high electrochemical activities towards the oxidation of doxorubicin and dacarbazine with peak-potential separation of 345 mV, which is sufficient for doxorubicin determination in the presence of dacarbazine. Also, the MWCNTs/ZnO nanocomposite-modified SPCE presented reproducible and stable responses to determine doxorubicin. Finally, the developed platform demonstrated a successful performance for doxorubicin and dacarbazine determination in real samples, with recovery in the range of 97.1% to 104.0% and relative standard deviation (RSD) from 1.8% to 3.5%. Full article

(This article belongs to the Special Issue Applications of Advanced Electrochemical (Bio)sensors in Environment, Food, and Medicine)

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15 pages, 2384 KiB

Open AccessArticle

Application of PS2M Aptamer as Receptor Layer for Electrochemical Detection of Lead Ions

by Izabela Zaras, Olga Kujawa, Marcin Olszewski and Marta Jarczewska

Biosensors 2025, 15(1), 59; https://doi.org/10.3390/bios15010059 - 17 Jan 2025

Viewed by 508

Abstract

Since lead can cause severe effects on living organisms’ health and life, the regular monitoring of Pb levels in water and soil is of particular significance. Recently, it was shown that lead ions can also be detected using affinity-based biosensors, namely, using aptamers [...] Read more.

Since lead can cause severe effects on living organisms’ health and life, the regular monitoring of Pb levels in water and soil is of particular significance. Recently, it was shown that lead ions can also be detected using affinity-based biosensors, namely, using aptamers as recognition elements. In most cases, thrombin binding aptamer (TBA) was utilized; however, there are more examples of DNA aptamers which could also serve that purpose. Herein, we present studies on the electrochemical detection of lead ions using PS2M aptamer, which contains several guanine nucleotides, as the receptor element. Firstly, the method of aptamer-based layer fabrication was optimized along with the choice of a redox active indicator, which was a source of current signal. The experiments revealed the possibility of lead ion detection from 50 to 600 nM, which covers the range below and above the maximum accepted limit stated by US EPA (72 nM). Moreover, the sensing layer exhibited high selectivity towards lead ions and was successfully applied both for the analysis of tap water spiked with Pb²⁺ ions and as a miniaturized sensor. Finally, stability and regeneration studies on the aptamer-based receptor layer were executed to confirm the utility of the elaborated tool. Full article

(This article belongs to the Special Issue Electrochemical DNA Biosensors)

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11 pages, 1851 KiB

Open AccessArticle

Rapid Detection of microRNA-122 in Serum and Finger Blood Using a Lateral Flow Nucleic Acid Biosensor

by Min Zhang, Meijing Ma, Jiahui Wang, Yurui Zhou, Xueji Zhang and Guodong Liu

Biosensors 2025, 15(1), 58; https://doi.org/10.3390/bios15010058 - 17 Jan 2025

Viewed by 607

Abstract

MicroRNA122 (miR-122) is a microRNA that is highly expressed in hepatocytes and has been identified as a prospective therapeutic target and biomarker for liver injury. An expanding body of research has demonstrated that miR-122 is a critical regulator in both the initiation and [...] Read more.

MicroRNA122 (miR-122) is a microRNA that is highly expressed in hepatocytes and has been identified as a prospective therapeutic target and biomarker for liver injury. An expanding body of research has demonstrated that miR-122 is a critical regulator in both the initiation and progression of a wide range of liver diseases. Traditional methods for detecting miR-122 mainly include Northern blotting and qRT-PCR, but they are technically complex and cumbersome, requiring expensive instruments and high technical requirements. In this paper, we present a novel rapid testing method utilizing a lateral flow nucleic acid biosensor (LFNAB) for the sensitive and time-efficient detection of miR-122. This approach offers several advantages, including a high specificity for miR-122, the ability to detect low concentrations of the target molecule, and a significantly reduced testing time compared to conventional detection methods. In this study, a thiol-modified single-stranded detection DNA probe (Det-DNA), a biotinylated single-stranded capture DNA probe (Cap-DNA), and a biotinylated single-stranded control DNA probe (Con-DNA) are used to construct the LFNAB. A gold nanoparticle (AuNP) is a colored tag, which is used to label the Det-DNA probe. The principle of detecting miR-122 is based on dual DNA-miRNA hybridization reactions on the LFNAB to form sandwich-type AuNP-Det-DNA-miR-122-Cap-DNA complexes, which are captured on the test area of LFNAB for visualization and quantification. After systematic optimization of conditions of experiment, the response of LFNAB was highly linear within the scope of 0 pM-100 pM miR-122, and the detection limit in 15 min was 3.90 pM. The use of LFNAB to detect miR-122 in serum and fingertip blood has yielded satisfactory results. This successful application indicates the effectiveness of LFNAB in detecting miR-122 in both serum and fingertip blood samples, showcasing its potential utility in clinical and research settings for assessing miR-122 levels in different biological samples. Full article

(This article belongs to the Special Issue Biosensors for Biomedical Diagnostics)

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20 pages, 6592 KiB

Open AccessReview

Electrochemical Biosensors 3D Printed by Fused Deposition Modeling: Actualities, Trends, and Challenges

by Luiz Ricardo Guterres Silva, Carlos Eduardo Costa Lopes, Auro Atsushi Tanaka, Luiza Maria Ferreira Dantas, Iranaldo Santos Silva and Jéssica Santos Stefano

Biosensors 2025, 15(1), 57; https://doi.org/10.3390/bios15010057 - 17 Jan 2025

Viewed by 801

Abstract

The technology of 3D printing, particularly fused deposition modeling (FDM) 3D printing, has revolutionized the development of electrochemical biosensors, offering a versatile and cost-effective approach for clinical applications. This review explores the integration of FDM in fabricating biosensing platforms tailored for clinical diagnostics, [...] Read more.

The technology of 3D printing, particularly fused deposition modeling (FDM) 3D printing, has revolutionized the development of electrochemical biosensors, offering a versatile and cost-effective approach for clinical applications. This review explores the integration of FDM in fabricating biosensing platforms tailored for clinical diagnostics, emphasizing its role in detecting various biomarkers and viral pathogens. Advances in 3D printing materials, especially the emergence of bespoke conductive filaments, have allowed the production of highly customizable and efficient biosensors. A detailed discussion focuses on the design and application of these biosensors for viral detection, highlighting their potential to improve diagnostic accuracy. Furthermore, the review addresses current trends, including the push towards miniaturization and multianalyte detection, alongside challenges such as material optimization and regulatory hurdles. By providing a comprehensive overview, this work underscores the transformative impact of 3D-printed electrochemical biosensors in clinical diagnostics while also identifying critical areas for future research and development. Full article

(This article belongs to the Special Issue Optical and Electrochemical Biosensors for Biological, Environmental, and Food Analysis)

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19 pages, 5726 KiB

Open AccessArticle

MOX Nanosensors to Detect Colorectal Cancer Relapses from Patient’s Blood at Three Years Follow-Up, and Gender Correlation

by Michele Astolfi, Giulia Zonta, Cesare Malagù, Gabriele Anania and Giorgio Rispoli

Biosensors 2025, 15(1), 56; https://doi.org/10.3390/bios15010056 - 16 Jan 2025

Viewed by 672

Abstract

Colorectal cancer represents 10% of all the annual tumors diagnosed worldwide, being often not timely diagnosed, because its symptoms are typically lacking or very mild. Therefore, it is crucial to develop and validate innovative low-invasive techniques to detect it before becoming intractable. To [...] Read more.

Colorectal cancer represents 10% of all the annual tumors diagnosed worldwide, being often not timely diagnosed, because its symptoms are typically lacking or very mild. Therefore, it is crucial to develop and validate innovative low-invasive techniques to detect it before becoming intractable. To this aim, a device equipped with nanostructured gas sensors has been employed to detect the airborne molecules of blood samples collected from healthy subjects, and from colorectal cancer affected patients at different stages of their pre- and post-surgery therapeutic path. Data was scrutinized by using statistical standard techniques to highlight their statistical differences, and through principal component analysis and support vector machine to classify them. The device was able to readily distinguish between the pre-surgery blood samples (i.e., taken when the patient had cancer), and the ones up to three years post-surgery (i.e., following the tumor removal) or the ones from healthy subjects. Finally, the correlation of the sensor responses with the patient/healthy subject’s gender was investigated, resulting negligible. These results pave the path toward a clinical validation of this device to monitor the patient’s health status by detecting possible relapses, to parallel to clinical follow-up protocols. Full article

(This article belongs to the Special Issue Nano Biosensors and Their Applications for In Vivo/Vitro Diagnosis—2nd Edition)

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14 pages, 4348 KiB

Open AccessArticle

Basic Characteristics of Ionic Liquid-Gated Graphene FET Sensors for Nitrogen Cycle Monitoring in Agricultural Soil

by Naoki Shiraishi, Jian Lu, Fatin Bazilah Fauzi, Ryo Imaizumi, Toyohiro Tsukahara, Satoshi Mogari, Shosuke Iida, Yusuke Matsukura, Satoshi Teramoto, Keisuke Yokoi, Izumi Ichinose and Mutsumi Kimura

Biosensors 2025, 15(1), 55; https://doi.org/10.3390/bios15010055 - 16 Jan 2025

Viewed by 549

Abstract

Nitrogen-based fertilizers are crucial in agriculture for maintaining soil health and increasing crop yields. Soil microorganisms transform nitrogen from fertilizers into

{N O}_{3}^{-}

–N, which is absorbed by crops. However, some nitrogen is converted to nitrous oxide (N₂O), a [...] Read more.

Nitrogen-based fertilizers are crucial in agriculture for maintaining soil health and increasing crop yields. Soil microorganisms transform nitrogen from fertilizers into

{N O}_{3}^{-}

–N, which is absorbed by crops. However, some nitrogen is converted to nitrous oxide (N₂O), a greenhouse gas with a warming potential about 300-times greater than carbon dioxide (CO₂). Agricultural activities are the main source of N₂O emissions. Monitoring N₂O can enhance soil health and optimize nitrogen fertilizer use, thereby supporting precision agriculture. To achieve this, we developed ionic liquid-gated graphene field-effect transistor (FET) sensors to measure N₂O concentrations in agricultural soil. We first fabricated and tested the electrical characteristics of the sensors. Then, we analyzed their transfer characteristics in our developed N₂O evaluation system using different concentrations of N₂O and air. The sensors demonstrated a negative shift in transfer characteristic curves when exposed to N₂O, with a Dirac point voltage difference of 0.02 V between 1 and 10 ppm N₂O diluted with pure air. These results demonstrate that the ionic liquid-gated graphene FET sensor is a promising device for N₂O detection for agricultural soil applications. Full article

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

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12 pages, 2012 KiB

Open AccessArticle

Aptamer-Conjugated Multi-Quantum Dot-Embedded Silica Nanoparticles for Lateral Flow Immunoassay

by Kwanghee Yoo, Hye-Seong Cho, Jaehi Kim, Minsup Shin, Jun-Sik Chu, Sohyeon Jang, Han-Joo Bae, Heung Su Jung, Homan Kang and Bong-Hyun Jun

Biosensors 2025, 15(1), 54; https://doi.org/10.3390/bios15010054 - 16 Jan 2025

Viewed by 587

Abstract

Lateral flow immunoassays (LFIAs) are widely used for their low cost, simplicity, and rapid results; however, enhancing their reliability requires the meticulous selection of ligands and nanoparticles (NPs). SiO₂@QD@SiO₂ (QD²) nanoparticles, which consist of quantum dots (QDs) embedded [...] Read more.

Lateral flow immunoassays (LFIAs) are widely used for their low cost, simplicity, and rapid results; however, enhancing their reliability requires the meticulous selection of ligands and nanoparticles (NPs). SiO₂@QD@SiO₂ (QD²) nanoparticles, which consist of quantum dots (QDs) embedded in a silica (SiO₂) core and surrounded by an outer SiO₂ shell, exhibit significantly higher fluorescence intensity (FI) compared to single QDs. In this study, we prepared QD²@PEG@Aptamer, an aptamer conjugated with QD² using succinimidyl-[(N-maleimidopropionamido)-hexaethyleneglycol]ester, which is 130 times brighter than single QDs, for detecting carbohydrate antigen (CA) 19-9 through LFIA. For LFIA optimization, we determined the optimal conditions as a 1.0:2.0 × 10⁻² ratio of polyethylene glycol (PEG) to aptamer by adjusting the amounts of PEG and aptamer, phosphate-buffered saline containing 0.5% Tween^® 20 as a developing solution, and 0.15 μg NPs by setting the NP weight during development. Under these conditions, QD²@PEG@Aptamer selectively detected CA19-9, achieving a detection limit of 1.74 × 10⁻² mg·mL⁻¹. Moreover, FI remained stable for 10 days after detection. These results highlight the potential of QD² and aptamer conjugation technology as a reliable and versatile sensing platform for various diagnostic applications. Full article

(This article belongs to the Special Issue Novel Nanomaterials and Nanotechnology: From Fabrication Methods and Improvement Strategies to Applications in Biosensing and Biomedicine (2nd Edition))

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30 pages, 13353 KiB

Open AccessReview

Wearable Sensors for Plants: Status and Prospects

by Xuexin Yan, Yawen Pang, Kaiwen Niu, Bowen Hu, Zhengbo Zhu, Zuojun Tan and Hongwei Lei

Biosensors 2025, 15(1), 53; https://doi.org/10.3390/bios15010053 - 15 Jan 2025

Viewed by 896

Abstract

The increasing demand for smart agriculture has led to the development of agricultural sensor technology. Wearable sensors show great potential for monitoring the physiological and surrounding environmental information for plants due to their high flexibility, biocompatibility, and scalability. However, wearable sensors for plants [...] Read more.

The increasing demand for smart agriculture has led to the development of agricultural sensor technology. Wearable sensors show great potential for monitoring the physiological and surrounding environmental information for plants due to their high flexibility, biocompatibility, and scalability. However, wearable sensors for plants face several challenges that hinder their large-scale practical application. In this review, we summarize the current research status of wearable plant sensors by analyzing the classification, working principles, sensor materials, and structural design and discussing the multifunctional applications. More importantly, we comment on the challenges the wearable plant sensors face and provide our perspectives on further improving the sensitivity, reliability, and stability of wearable plant sensors for future smart agriculture. Full article

(This article belongs to the Special Issue Recent Progress in Wearable Biosensors: Materials, Functions and Applications)

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11 pages, 5003 KiB

Open AccessArticle

SERS Detection of Hydrophobic Molecules: Thio-β-Cyclodextrin-Driven Rapid Self-Assembly of Uniform Silver Nanoparticle Monolayers and Analyte Trapping

by Qi Yuan and Yunqing Wang

Biosensors 2025, 15(1), 52; https://doi.org/10.3390/bios15010052 - 15 Jan 2025

Viewed by 508

Abstract

High-sensitivity and repeatable detection of hydrophobic molecules through the surface-enhanced Raman scattering (SERS) technique is a tough challenge because of their weak adsorption and non-uniform distribution on SERS substrates. In this research, we present a simple self-assembly protocol for monolayer SERS mediated by [...] Read more.

High-sensitivity and repeatable detection of hydrophobic molecules through the surface-enhanced Raman scattering (SERS) technique is a tough challenge because of their weak adsorption and non-uniform distribution on SERS substrates. In this research, we present a simple self-assembly protocol for monolayer SERS mediated by 6-deoxy-6-thio-β-cyclodextrin (β-CD-SH). This protocol allows for the rapid assembly of a compact silver nanoparticle (Ag NP) monolayer at the oil/water interface within 40 s, while entrapping analyte molecules within hotspots. The proposed method shows general applicability for detecting hydrophobic molecules, exemplified as Nile blue, Nile red, fluconazole, carbendazim, benz[a]anthracene, and bisphenol A. The detection limits range from 10⁻⁶to 10⁻⁹ M, and the relative standard deviations (RSDs) of signal intensity are less than 10%. Moreover, this method was used to investigate the release behaviors of a hydrophobic pollutant (Nile blue) adsorbed on the nanoplastic surface in the water environment. The results suggest that elevated temperatures, increased salinities, and the coexistence of fulvic acid promote the release of Nile blue. This simple and fast protocol overcomes the difficulties related to hotspot accessibility and detection repeatability for hydrophobic analytes, holding out extensive application prospects in environmental monitoring and chemical analysis. Full article

(This article belongs to the Special Issue Miniature Sensors Based on Highly Efficient Chemical and Biological Sensing Interfaces)

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35 pages, 3819 KiB

Open AccessReview

Next-Generation Potentiometric Sensors: A Review of Flexible and Wearable Technologies

by Mahmoud Abdelwahab Fathy and Philippe Bühlmann

Biosensors 2025, 15(1), 51; https://doi.org/10.3390/bios15010051 - 15 Jan 2025

Viewed by 803

Abstract

In recent years, the field of wearable sensors has undergone significant evolution, emerging as a pivotal topic of research due to the capacity of such sensors to gather physiological data during various human activities. Transitioning from basic fitness trackers, these sensors are continuously [...] Read more.

In recent years, the field of wearable sensors has undergone significant evolution, emerging as a pivotal topic of research due to the capacity of such sensors to gather physiological data during various human activities. Transitioning from basic fitness trackers, these sensors are continuously being improved, with the ultimate objective to make compact, sophisticated, highly integrated, and adaptable multi-functional devices that seamlessly connect to clothing or the body, and continuously monitor bodily signals without impeding the wearer’s comfort or well-being. Potentiometric sensors, leveraging a range of different solid contact materials, have emerged as a preferred choice for wearable chemical or biological sensors. Nanomaterials play a pivotal role, offering unique properties, such as high conductivity and surface-to-volume ratios. This article provides a review of recent advancements in wearable potentiometric sensors utilizing various solid contacts, with a particular emphasis on nanomaterials. These sensors are employed for precise ion concentration determinations, notably sodium, potassium, calcium, magnesium, ammonium, and chloride, in human biological fluids. This review highlights two primary applications, that is, (1) the enhancement of athletic performance by continuous monitoring of ion levels in sweat to gauge the athlete’s health status, and (2) the facilitation of clinical diagnosis and preventive healthcare by monitoring the health status of patients, in particular to detect early signs of dehydration, fatigue, and muscle spasms. Full article

(This article belongs to the Special Issue Advances in Portable and Wearable Sensing Systems for Biochemical Monitoring)

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9 pages, 1393 KiB

Open AccessArticle

Resonant Young’s Slit Interferometer for Sensitive Detection of Low-Molecular-Weight Biomarkers

by Stefanus Renaldi Wijaya, Augusto Martins, Katie Morris, Steven D. Quinn and Thomas F. Krauss

Biosensors 2025, 15(1), 50; https://doi.org/10.3390/bios15010050 - 15 Jan 2025

Viewed by 562

Abstract

The detection of low-molecular-weight biomarkers is essential for diagnosing and managing various diseases, including neurodegenerative conditions such as Alzheimer’s disease. A biomarker’s low molecular weight is a challenge for label-free optical modalities, as the phase change they detect is directly proportional to the [...] Read more.

The detection of low-molecular-weight biomarkers is essential for diagnosing and managing various diseases, including neurodegenerative conditions such as Alzheimer’s disease. A biomarker’s low molecular weight is a challenge for label-free optical modalities, as the phase change they detect is directly proportional to the mass bound on the sensor’s surface. To address this challenge, we used a resonant Young’s slit interferometer geometry and implemented several innovations, such as phase noise matching and optimisation of the fringe spacing, to maximise the signal-to-noise ratio. As a result, we achieved a limit of detection of 2.9 × 10⁻⁶ refractive index units (RIU). We validated our sensor’s low molecular weight capability by demonstrating the detection of Aβ-42, a 4.5 kDa peptide indicative of Alzheimer’s disease, and reached the clinically relevant pg/mL regime. This system builds on the guided mode resonance modality we previously showed to be compatible with handheld operation using low-cost components. We expect this development will have far-reaching applications beyond Aβ-42 and become a workhorse tool for the label-free detection of low-molecular-weight biomarkers across a range of disease types. Full article

(This article belongs to the Special Issue Lighting Up Single-Molecule Biosensors and Bioimaging: Now and the Decade to Come)

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11 pages, 3947 KiB

Open AccessArticle

BSA-Assisted Synthesis of Au Nanoclusters/MnO₂ Nanosheets for Fluorescence “Switch-On” Detection of Alkaline Phosphatase

by Yijiong Xue, Chengqi Bao, Hui Liu, Fanghui Ma, Minghui Yang and Xiaoqing Li

Biosensors 2025, 15(1), 49; https://doi.org/10.3390/bios15010049 - 15 Jan 2025

Viewed by 530

Abstract

A fluorescence probe for “switch-on” detection of alkaline phosphatase (ALP) was developed based on Au nanoclusters anchored MnO₂ nanosheets (Au NCs-MnO₂ NSs), which were synthesized using bovine serum albumin (BSA) as template through a simple one-pot approach. In the sensing system, [...] Read more.

A fluorescence probe for “switch-on” detection of alkaline phosphatase (ALP) was developed based on Au nanoclusters anchored MnO₂ nanosheets (Au NCs-MnO₂ NSs), which were synthesized using bovine serum albumin (BSA) as template through a simple one-pot approach. In the sensing system, MnO₂ NSs function as both energy acceptors and target identifiers, effectively quenches the fluorescence of Au NCs via fluorescence resonance energy transfer (FRET). The presence of ALP catalyzes the hydrolysis of L-ascorbic acid-2-phosphate (AAP) to ascorbic acid (AA), reducing MnO₂ NSs to Mn²⁺ and facilitate the fluorescence recovery of Au NCs. The fluorescence assay offers the advantages of facile preparation, cost-effectiveness, good specificity, and high sensitivity. Moreover, the assay exhibits a broad linear range (0.005 U/mL to 8 U/mL) for ALP detection with a remarkable limit of detection of 0.0015 U/mL. Notably, this assay demonstrates promising applicability for detection ALP in human serum samples, thereby providing valuable potential for clinical applications. Full article

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

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13 pages, 2954 KiB

Open AccessArticle

A Microfluidic Paper-Based Device for Monitoring Urease Activity in Saliva

by Francisca T. S. M. Ferreira, António O. S. S. Rangel and Raquel B. R. Mesquita

Biosensors 2025, 15(1), 48; https://doi.org/10.3390/bios15010048 - 15 Jan 2025

Viewed by 513

Abstract

Chronic Kidney Disease (CKD) is a disorder that affects over 10% of the global population, and that would benefit from innovative methodologies that would provide early detection. Since it has been reported that there are high levels of urease in CKD patients’ saliva, [...] Read more.

Chronic Kidney Disease (CKD) is a disorder that affects over 10% of the global population, and that would benefit from innovative methodologies that would provide early detection. Since it has been reported that there are high levels of urease in CKD patients’ saliva, this sample is a promising non-invasive alternative to blood for CKD detection and monitoring. This work introduces a novel 3D µPAD for quantifying urease activity in saliva in a range of 0.041–0.750 U/mL, with limits of detection and quantification of 0.012 and 0.041 U/mL, respectively. The device uses the urease in the sample to convert urea into ammonia, causing a colorimetric change in the bromothymol blue. The accuracy of the developed device was evaluated by comparing the measurements of several saliva samples (#13) obtained with the μPAD and with a commercially available kit. Stability studies were also performed to assess its functionality as a point-of-care methodology, and the device was stable for 4 months when stored in a vacuum. After the sample placement, it could be scanned within 40 min without providing significantly different results. The developed device quantifies urease activity in saliva within 30 min, providing a simple, portable, lab-free alternative to existing methodologies. Full article

(This article belongs to the Special Issue Microfluidics for Biomedical Applications (3rd Edition))

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11 pages, 1660 KiB

Open AccessArticle

Enhanced Electrochemiluminescence from Ruthenium-Tagged Immune Complex at Flexible Chains for Sensitive Analysis of Glutamate Decarboxylase Antibody

by Yuyao Zhang, Li Qian, Qian Zhang, Yu Li, Yu Liu and Dechen Jiang

Biosensors 2025, 15(1), 47; https://doi.org/10.3390/bios15010047 - 15 Jan 2025

Viewed by 490

Abstract

Herein, a sensitive electrochemiluminescence (ECL) immunosensor is designed by immobilizing ruthenium-tagged immune complexes at flexible poly-ethylene-glycol (PEG) chains on the electrode surface, which offers more freedom for the collision of the ruthenium complex at the electrode during the initial ECL reaction. The electrochemical [...] Read more.

Herein, a sensitive electrochemiluminescence (ECL) immunosensor is designed by immobilizing ruthenium-tagged immune complexes at flexible poly-ethylene-glycol (PEG) chains on the electrode surface, which offers more freedom for the collision of the ruthenium complex at the electrode during the initial ECL reaction. The electrochemical characterizations confirm the loose structure of the assembled layer with the immune complex, providing an increase in the current and the resultant enhanced ECL emissions. Comparing the sensors with the rigid structure, a 34-fold increase in the maximal ECL emission is recorded when PEG3400 is used as a linker. Using the optimized protocol, the prepared immunosensor exhibits a wide-ranging linear response to the model antibody (glutamate decarboxylase antibody) ranging from 10 pg/mL to 10 ng/mL. The detection limit is almost two orders lower than the value using the classic enzyme-linked immunosorbent assay, which offers a new design to enhance ECL emissions and the resultant analytical performance. Full article

(This article belongs to the Special Issue Feature Papers of Biosensors)

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12 pages, 6487 KiB

Open AccessArticle

Mapping Surface Potential in DNA Aptamer–Neurochemical and Membrane–Ion Interactions on the SOS Substrate Using Terahertz Microscopy

by Kosei Morita, Yuta Mitsuda, Sota Yoshida, Toshihiko Kiwa and Jin Wang

Biosensors 2025, 15(1), 46; https://doi.org/10.3390/bios15010046 - 13 Jan 2025

Viewed by 656

Abstract

In this study, we utilized a terahertz chemical microscope (TCM) to map surface potential changes induced by molecular interactions on silicon-on-sapphire (SOS) substrates. By functionalizing the SOS substrate with DNA aptamers and an ion-selective membrane, we successfully detected and visualized aptamer–neurochemical complexes through [...] Read more.

In this study, we utilized a terahertz chemical microscope (TCM) to map surface potential changes induced by molecular interactions on silicon-on-sapphire (SOS) substrates. By functionalizing the SOS substrate with DNA aptamers and an ion-selective membrane, we successfully detected and visualized aptamer–neurochemical complexes through the terahertz amplitude. Additionally, comparative studies of DNA aptamers in PBS buffer and artificial cerebrospinal fluid (aCSF) were performed by computational structure modeling and terahertz measurements. Beyond neurochemicals, we also investigated calcium ions, measuring their concentrations in PDMS-fabricated micro-wells using minimal sample volumes. Our results highlight the capability of TCM as a powerful, label-free, and sensitive platform for the probing and mapping of surface potential arising from molecular interactions, with broad implications for biomedical diagnostics and research. Full article

(This article belongs to the Special Issue Advancing Biomedical Biosensing with Microelectrode Arrays)

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15 pages, 6362 KiB

Open AccessArticle

An Integrated Microfluidic Microwave Array Sensor with Machine Learning for Enrichment and Detection of Mixed Biological Solution

by Sen Yang, Yanxiong Wang, Yanfeng Jiang and Tian Qiang

Biosensors 2025, 15(1), 45; https://doi.org/10.3390/bios15010045 - 13 Jan 2025

Viewed by 602

Abstract

In this work, an integrated microfluidic microwave array sensor is proposed for the enrichment and detection of mixed biological solution. In individuals with urinary tract infections or intestinal health issues, the levels of white blood cells (WBCs) and Escherichia coli (E. coli [...] Read more.

In this work, an integrated microfluidic microwave array sensor is proposed for the enrichment and detection of mixed biological solution. In individuals with urinary tract infections or intestinal health issues, the levels of white blood cells (WBCs) and Escherichia coli (E. coli) in urine or intestinal extracts can be significantly elevated compared to normal. The proposed integrated chip, characterized by its low cost, simplicity of operation, fast response, and high accuracy, is designed to detect a mixed solution of WBCs and E. coli. The results demonstrate that microfluidics could effectively enrich WBCs with an efficiency of 88.3%. For WBC detection, the resonance frequency of the sensing chip decreases with increasing concentration, while for E. coli detection, the capacitance value of the sensing chip increases with elevated concentration. Furthermore, the measurement data are processed using machine learning. Specifically, the WBC measurement data are subjected to a further linear fitting. In addition, the prediction model for E. coli concentration, employing four different algorithms, achieves a maximum accuracy of 95.24%. Consequently, the proposed integrated chip can be employed for the clinical diagnosis of WBCs and E. coli, providing a novel approach for medical and biological research involving cells and bacteria. Full article

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

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36 pages, 1986 KiB

Open AccessReview

Exploring Innovative Approaches for the Analysis of Micro- and Nanoplastics: Breakthroughs in (Bio)Sensing Techniques

by Denise Margarita Rivera-Rivera, Gabriela Elizabeth Quintanilla-Villanueva, Donato Luna-Moreno, Araceli Sánchez-Álvarez, José Manuel Rodríguez-Delgado, Erika Iveth Cedillo-González, Garima Kaushik, Juan Francisco Villarreal-Chiu and Melissa Marlene Rodríguez-Delgado

Biosensors 2025, 15(1), 44; https://doi.org/10.3390/bios15010044 - 13 Jan 2025

Viewed by 1097

Abstract

Plastic pollution, particularly from microplastics (MPs) and nanoplastics (NPs), has become a critical environmental and health concern due to their widespread distribution, persistence, and potential toxicity. MPs and NPs originate from primary sources, such as cosmetic microspheres or synthetic fibers, and secondary fragmentation [...] Read more.

Plastic pollution, particularly from microplastics (MPs) and nanoplastics (NPs), has become a critical environmental and health concern due to their widespread distribution, persistence, and potential toxicity. MPs and NPs originate from primary sources, such as cosmetic microspheres or synthetic fibers, and secondary fragmentation of larger plastics through environmental degradation. These particles, typically less than 5 mm, are found globally, from deep seabeds to human tissues, and are known to adsorb and release harmful pollutants, exacerbating ecological and health risks. Effective detection and quantification of MPs and NPs are essential for understanding and mitigating their impacts. Current analytical methods include physical and chemical techniques. Physical methods, such as optical and electron microscopy, provide morphological details but often lack specificity and are time-intensive. Chemical analyses, such as Fourier transform infrared (FTIR) and Raman spectroscopy, offer molecular specificity but face challenges with smaller particle sizes and complex matrices. Thermal analytical methods, including pyrolysis gas chromatography–mass spectrometry (Py-GC-MS), provide compositional insights but are destructive and limited in morphological analysis. Emerging (bio)sensing technologies show promise in addressing these challenges. Electrochemical biosensors offer cost-effective, portable, and sensitive platforms, leveraging principles such as voltammetry and impedance to detect MPs and their adsorbed pollutants. Plasmonic techniques, including surface plasmon resonance (SPR) and surface-enhanced Raman spectroscopy (SERS), provide high sensitivity and specificity through nanostructure-enhanced detection. Fluorescent biosensors utilizing microbial or enzymatic elements enable the real-time monitoring of plastic degradation products, such as terephthalic acid from polyethylene terephthalate (PET). Advancements in these innovative approaches pave the way for more accurate, scalable, and environmentally compatible detection solutions, contributing to improved monitoring and remediation strategies. This review highlights the potential of biosensors as advanced analytical methods, including a section on prospects that address the challenges that could lead to significant advancements in environmental monitoring, highlighting the necessity of testing the new sensing developments under real conditions (composition/matrix of the samples), which are often overlooked, as well as the study of peptides as a novel recognition element in microplastic sensing. Full article

(This article belongs to the Special Issue Micro-nano Optic-Based Biosensing Technology and Strategy)

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10 pages, 2538 KiB

Open AccessArticle

Rapid Acquisition of High-Pixel Fluorescence Lifetime Images of Living Cells via Image Reconstruction Based on Edge-Preserving Interpolation

by Yinru Zhu, Yong Guo, Xinwei Gao, Qinglin Chen, Yingying Chen, Ruijie Xiang, Baichang Lin, Luwei Wang, Yuan Lu and Wei Yan

Biosensors 2025, 15(1), 43; https://doi.org/10.3390/bios15010043 - 13 Jan 2025

Viewed by 569

Abstract

Fluorescence lifetime imaging (FLIM) has established itself as a pivotal tool for investigating biological processes within living cells. However, the extensive imaging duration necessary to accumulate sufficient photons for accurate fluorescence lifetime calculations poses a significant obstacle to achieving high-resolution monitoring of cellular [...] Read more.

Fluorescence lifetime imaging (FLIM) has established itself as a pivotal tool for investigating biological processes within living cells. However, the extensive imaging duration necessary to accumulate sufficient photons for accurate fluorescence lifetime calculations poses a significant obstacle to achieving high-resolution monitoring of cellular dynamics. In this study, we introduce an image reconstruction method based on the edge-preserving interpolation method (EPIM), which transforms rapidly acquired low-resolution FLIM data into high-pixel images, thereby eliminating the need for extended acquisition times. Specifically, we decouple the grayscale image and the fluorescence lifetime matrix and perform an individual interpolation on each. Following the interpolation of the intensity image, we apply wavelet transformation and adjust the wavelet coefficients according to the image gradients. After the inverse transformation, the original image is obtained and subjected to noise reduction to complete the image reconstruction process. Subsequently, each pixel is pseudo-color-coded based on its intensity and lifetime, preserving both structural and temporal information. We evaluated the performance of the bicubic interpolation method and our image reconstruction approach on fluorescence microspheres and fixed-cell samples, demonstrating their effectiveness in enhancing the quality of lifetime images. By applying these techniques to live-cell imaging, we can successfully obtain high-pixel FLIM images at shortened intervals, facilitating the capture of rapid cellular events. Full article

(This article belongs to the Special Issue Fluorescent Materials with Excellent Biocompatibility and Their Application in Bio-Sensing, Bio-Imaging (Volume II))

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17 pages, 2598 KiB

Open AccessArticle

Anti-Tissue-Transglutaminase IgA Antibodies Presence Determination Using Electrochemical Square Wave Voltammetry and Modified Electrodes Based on Polypyrrole and Quantum Dots

by Angela Gabriela Pãun, Simona Popescu, Alisa Ioana Ungureanu, Roxana Trusca, Alina Popp, Cristina Dumitriu and George-Octavian Buica

Biosensors 2025, 15(1), 42; https://doi.org/10.3390/bios15010042 - 13 Jan 2025

Viewed by 609

Abstract

A novel electrochemical detection method utilizing a cost-effective hybrid-modified electrode has been established. A glassy carbon (GC) modified electrode was tested for its ability to measure electrochemical tTG antibody levels, which are essential for diagnosing and monitoring Celiac disease (CD). Tissue transglutaminase protein [...] Read more.

A novel electrochemical detection method utilizing a cost-effective hybrid-modified electrode has been established. A glassy carbon (GC) modified electrode was tested for its ability to measure electrochemical tTG antibody levels, which are essential for diagnosing and monitoring Celiac disease (CD). Tissue transglutaminase protein biomolecules are immobilized on a quantum dots-polypyrrole nanocomposite in the improved electrode. Initial, quantum dots (QDs) were obtained from Bombyx mori silk fibroin and embedded in polypyrrole film. Using carbodiimide coupling, a polyamidoamine (PAMAM) dendrimer was linked with GQDs-polypyrrole film to improve sensor sensitivity. The tissue transglutaminase (tTG) antigen was cross-linked onto PAMAM using N-(3-dimethylaminopropyl)-N′-ethylcarbodiimide hydrochloride (EDC)-N-hydroxy succinimide (NHS) chemistry to develop a nanoprobe that can detect human serum anti-tTG antibodies. The physicochemical characteristics of the synthesized nanocomposite were examined by FTIR, UV-visible, FE-SEM, EDX, and electrochemical studies. The novel electrode measures anti-tissue antibody levels in real time using human blood serum samples. The modified electrode has great repeatability and an 8.7 U/mL detection limit. Serum samples from healthy people and CD patients were compared to standard ELISA kit assays. SPSS and Excel were used for statistical analysis. The improved electrode and detection system can identify anti-tissue antibodies up to 80 U/mL. Full article

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

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20 pages, 4215 KiB

Open AccessReview

Pioneering Role of Nanopore Single-Molecule Sensing in Environmental and Food Surveillance

by Wenqiang Tian, Xu Wang, Yan Zhang, Ting Weng, Tlili Chaker, Xiaohan Chen, Qingke Kong and Deqiang Wang

Biosensors 2025, 15(1), 41; https://doi.org/10.3390/bios15010041 - 13 Jan 2025

Viewed by 592

Abstract

In recent years, environmental and food safety have garnered substantial focus due to their intimate connection with human health. Numerous biosensors have been developed for identifying deleterious compounds; however, these biosensors reveal certain limitations. Nanopore sensors, featuring nano-scaled pore size, have demonstrated outstanding [...] Read more.

In recent years, environmental and food safety have garnered substantial focus due to their intimate connection with human health. Numerous biosensors have been developed for identifying deleterious compounds; however, these biosensors reveal certain limitations. Nanopore sensors, featuring nano-scaled pore size, have demonstrated outstanding performance in terms of rapidity, sensitivity, and selectivity as a single-molecule technique for environmental and food surveillance. In this review, we present a comprehensive overview of nanopore applications in these two fields. To elucidate the pioneering roles of nanopores, analytes are categorized into three distinct groups, including metal ions, synthetic contaminants, and biotoxins. Moreover, a variety of strategies are involved, such as the coalescence with ligand probes, the implementation of chemical reactions, the functionalization of nanopores, etc. These scientific studies showcase the versatility and diversity of the nanopore technique, paving the way for further developments of nanopore technology in environmental and food safety. Full article

(This article belongs to the Special Issue Biosensors for Environmental Monitoring and Food Safety)

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17 pages, 6994 KiB

Open AccessArticle

MicroVi: A Cost-Effective Microscopy Solution for Yeast Cell Detection and Count in Wine Value Chain

by Ismael Benito-Altamirano, Sergio Moreno, David M. Vaz-Romero, Anna Puig-Pujol, Gemma Roca-Domènech, Joan Canals, Anna Vilà, Joan Daniel Prades and Ángel Diéguez

Biosensors 2025, 15(1), 40; https://doi.org/10.3390/bios15010040 - 12 Jan 2025

Viewed by 779

Abstract

In recent years, the wine industry has been researching how to improve wine quality along the production value chain. In this scenario, we present here a new tool, MicroVi, a cost-effective chip-sized microscopy solution to detect and count yeast cells in wine samples. [...] Read more.

In recent years, the wine industry has been researching how to improve wine quality along the production value chain. In this scenario, we present here a new tool, MicroVi, a cost-effective chip-sized microscopy solution to detect and count yeast cells in wine samples. We demonstrate that this novel microscopy setup is able to measure the same type of samples as an optical microscopy system, but with smaller size equipment and with automated cell count configuration. The technology relies on the top of state-of-the-art computer vision pipelines to post-process the images and count the cells. A typical pipeline consists of normalization, feature extraction (i.e., SIFT), image composition (to increase both resolution and scanning area), holographic reconstruction and particle count (i.e., Hough transform). MicroVi achieved a 2.19 µm resolution by properly resolving the G7.6 features from the USAF Resolving Power Test Target 1951. Additionally, we aimed for a successful calibration of cell counts for Saccharomyces cerevisiae. We compared our direct results with our current optical setup, achieving a linear calibration for measurements ranging from 0.5 to 50 million cells per milliliter. Furthermore, other yeast cells were qualitatively resolved with our MicroVi microscope, such as, Brettanomyces bruxellensis, or bacteria, like, Lactobacillus plantarum, thus confirming the system’s reliability for consistent microbial assessment. Full article

(This article belongs to the Special Issue Trends in Optical Biosensing and Bioimaging)

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22 pages, 7906 KiB

Open AccessArticle

Developing a Label-Free Infrared Spectroscopic Analysis with Chemometrics and Computational Enhancement for Assessing Lupus Nephritis Activity

by Mei-Ching Yu, Xiang-Di Huang, Chin-Wei Kuo, Kai-Fu Zhang, Ping-Chung Liang, U-Ser Jeng, Pei-Yu Huang, Frederick Wai Keung Tam and Yao-Chang Lee

Biosensors 2025, 15(1), 39; https://doi.org/10.3390/bios15010039 - 11 Jan 2025

Viewed by 575

Abstract

Patterns of disease and therapeutic responses vary widely among patients with autoimmune glomerulonephritis. This study introduces groundbreaking personalized infrared (IR)-based diagnostics for real-time monitoring of disease status and treatment responses in lupus nephritis (LN). We have established a relative absorption difference (RAD) equation [...] Read more.

Patterns of disease and therapeutic responses vary widely among patients with autoimmune glomerulonephritis. This study introduces groundbreaking personalized infrared (IR)-based diagnostics for real-time monitoring of disease status and treatment responses in lupus nephritis (LN). We have established a relative absorption difference (RAD) equation to assess characteristic spectral indices based on the temporal peak heights (PHs) of two characteristic serum absorption bands: ν₁ as the target signal and ν₂ as the PH reference for the ν₁ absorption band, measured at each dehydration time (t) during dehydration. The RAD gap (Ψ), defined as the difference in the RAD values between the initial and final stages of serum dehydration, enables the measurement of serum levels of IgG glycosylation (ν₁ (1030 cm⁻¹), ν₂ (1171 cm⁻¹)), serum lactate (ν₁ (1021 cm⁻¹), ν₂ (1171 cm⁻¹)), serum hydrophobicity (ν₁ (2930 cm⁻¹), ν₂ (2960 cm⁻¹)), serum hydrophilicity (ν₁ (1550 cm⁻¹), ν₂ (1650 cm⁻¹)), and albumin (ν₁ (1400 cm⁻¹), ν₂ (1450 cm⁻¹)). Furthermore, this IR-based assay incorporates an innovative algorithm and our proprietary iPath software (ver. 1.0), which calculates the prognosis prediction function (PPF, Φ) from the RAD gaps of five spectral markers and correlates these with conventional clinical renal biomarkers. We propose that this algorithm-assisted, IR-based approach can augment the patient-centric care of LN patients, particularly by focusing on changes in serum IgG glycosylation. Full article

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

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28 pages, 2948 KiB

Open AccessReview

Integration of Functional Materials in Photonic and Optoelectronic Technologies for Advanced Medical Diagnostics

by Naveen Thanjavur, Laxmi Bugude and Young-Joon Kim

Biosensors 2025, 15(1), 38; https://doi.org/10.3390/bios15010038 - 10 Jan 2025

Viewed by 1099

Abstract

Integrating functional materials with photonic and optoelectronic technologies has revolutionized medical diagnostics, enhancing imaging and sensing capabilities. This review provides a comprehensive overview of recent innovations in functional materials, such as quantum dots, perovskites, plasmonic nanomaterials, and organic semiconductors, which have been instrumental [...] Read more.

Integrating functional materials with photonic and optoelectronic technologies has revolutionized medical diagnostics, enhancing imaging and sensing capabilities. This review provides a comprehensive overview of recent innovations in functional materials, such as quantum dots, perovskites, plasmonic nanomaterials, and organic semiconductors, which have been instrumental in the development of diagnostic devices characterized by high sensitivity, specificity, and resolution. Their unique optical properties enable real-time monitoring of biological processes, advancing early disease detection and personalized treatment. However, challenges such as material stability, reproducibility, scalability, and environmental sustainability remain critical barriers to their clinical translation. Breakthroughs such as green synthesis, continuous flow production, and advanced surface engineering are addressing these limitations, paving the way for next-generation diagnostic tools. This article highlights the transformative potential of interdisciplinary research in overcoming these challenges and emphasizes the importance of sustainable and scalable strategies for harnessing functional materials in medical diagnostics. The ultimate goal is to inspire further innovation in the field, enabling the creation of practical, cost-effective, and environmentally friendly diagnostic solutions. Full article

(This article belongs to the Special Issue Advances in Electrochemical, Photonic and Optoelectronic Biosensor Technologies for Rapid Point-of-Care Diagnostics)

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26 pages, 8161 KiB

Open AccessReview

Recent Progress in Self-Healing Triboelectric Nanogenerators for Artificial Skins

by Guoliang Li, Zongxia Li, Haojie Hu, Baojin Chen, Yuan Wang, Yanchao Mao, Haidong Li and Baosen Zhang

Biosensors 2025, 15(1), 37; https://doi.org/10.3390/bios15010037 - 10 Jan 2025

Viewed by 685

Abstract

Self-healing triboelectric nanogenerators (TENGs), which incorporate self-healing materials capable of recovering their structural and functional properties after damage, are transforming the field of artificial skin by effectively addressing challenges associated with mechanical damage and functional degradation. This review explores the latest advancements in [...] Read more.

Self-healing triboelectric nanogenerators (TENGs), which incorporate self-healing materials capable of recovering their structural and functional properties after damage, are transforming the field of artificial skin by effectively addressing challenges associated with mechanical damage and functional degradation. This review explores the latest advancements in self-healing TENGs, emphasizing material innovations, structural designs, and practical applications. Key materials include dynamic covalent polymers, supramolecular elastomers, and ion-conductive hydrogels, which provide rapid damage recovery, superior mechanical strength, and stable electrical performance. Innovative structural configurations, such as layered and encapsulated designs, optimize triboelectric efficiency and enhance environmental adaptability. Applications span healthcare, human–machine interfaces, and wearable electronics, demonstrating the immense potential for tactile sensing and energy harvesting. Despite significant progress, challenges remain in scalability, long-term durability, and multifunctional integration. Future research should focus on advanced material development, scalable fabrication, and intelligent system integration to unlock the full potential of self-healing TENGs. This review provides a comprehensive overview of current achievements and future directions, underscoring the pivotal role of self-healing TENGs in artificial skin technology. Full article

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

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15 pages, 6331 KiB

Open AccessArticle

Digital Melting Curve Analysis for Multiplex Quantification of Nucleic Acids on Droplet Digital PCR

by Xiaoqing Dai, Meng Cao and Zunliang Wang

Biosensors 2025, 15(1), 36; https://doi.org/10.3390/bios15010036 - 10 Jan 2025

Viewed by 561

Abstract

We present a cost-effective and simple multiplex nucleic acid quantification method using droplet digital PCR (ddPCR) with digital melting curve analysis (MCA). This approach eliminates the need for complex fluorescent probe design, reducing both costs and dependence on fluorescence channels. We developed a [...] Read more.

We present a cost-effective and simple multiplex nucleic acid quantification method using droplet digital PCR (ddPCR) with digital melting curve analysis (MCA). This approach eliminates the need for complex fluorescent probe design, reducing both costs and dependence on fluorescence channels. We developed a convolutional neighborhood search algorithm to correct droplet displacement during heating, ensuring precise tracking and accurate extraction of melting curves. An experimental protocol for digital MCA on the ddPCR platform was established, enabling accurate quantification of six target pathogen genes using a single fluorescence channel, with an average accuracy of 85%. Our method overcomes the multiplexing limitations of ddPCR, facilitating its application in multi-target pathogen detection. Full article

(This article belongs to the Special Issue Design, Fabrication, and Applications of Microfluidic Devices for Biosensing)

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44 pages, 7218 KiB

Open AccessReview

Surface Plasmon Resonance-Based Biodetection Systems: Principles, Progress and Applications—A Comprehensive Review

by Muhammad A. Butt

Biosensors 2025, 15(1), 35; https://doi.org/10.3390/bios15010035 - 9 Jan 2025

Viewed by 769

Abstract

Surface Plasmon Resonance (SPR)-based biodetection systems have emerged as powerful tools for real-time, label-free biomolecular interaction analysis, revolutionizing fields such as diagnostics, drug discovery, and environmental monitoring. This review highlights the foundational principles of SPR, focusing on the interplay of evanescent waves and [...] Read more.

Surface Plasmon Resonance (SPR)-based biodetection systems have emerged as powerful tools for real-time, label-free biomolecular interaction analysis, revolutionizing fields such as diagnostics, drug discovery, and environmental monitoring. This review highlights the foundational principles of SPR, focusing on the interplay of evanescent waves and surface plasmons that underpin its high sensitivity and specificity. Recent advancements in SPR technology, including enhancements in sensor chip materials, integration with nanostructures, and coupling with complementary detection techniques, are discussed to showcase their role in improving analytical performance. The paper also explores diverse applications of SPR biodetection systems, ranging from pathogen detection and cancer biomarker identification to food safety monitoring and environmental toxin analysis. By providing a comprehensive overview of technological progress and emerging trends, this review underscores the transformative potential of SPR-based biodetection systems in addressing critical scientific and societal challenges. Future directions and challenges, including miniaturization, cost reduction, and expanding multiplexing capabilities, are also presented to guide ongoing research and development in this rapidly evolving field. Full article

(This article belongs to the Special Issue Micro-nano Optic-Based Biosensing Technology and Strategy)

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