Pub Date : 2025-10-20DOI: 10.1016/j.biosx.2025.100702
Younghwan Kim , Swomitra Kumar Mohanty
Portable and mobile biosensors are widely applied in point-of-care (POC) diagnostics due to their rapid response and suitability for decentralized testing. While DNA-based probes have been commonly used in electrochemical biosensors owing to their label-free operation, low cost, and sensitivity, their susceptibility to enzymatic degradation and low thermal stability has limited their broader utility. As an alternative, peptide nucleic acid (PNA) probes have gained increasing attention due to their synthetic backbone, which is based on an electrically neutral N-(2-aminoethyl)glycine (AEG) structure. This neutrality confers high resistance to nucleases and polymerases, while enabling stronger and more stable hybridization with negatively charged DNA targets. PNA probes also maintain structural integrity under low ionic strength conditions, improving signal stability compared to conventional DNA probes. These advantages have led to a growing body of research exploring PNA-based biosensors for portable applications. This mini-review surveys recent developments in this area, focusing on the physicochemical properties of PNA and their implications for biosensor design. Future directions for PNA biosensor development are also discussed. Representative studies on electrode architectures and detection strategies are highlighted, demonstrating the potential of PNA-based systems to support next-generation portable diagnostics.
{"title":"PNA-based biosensors for portable electrochemical diagnostics: Integration strategies and probe design","authors":"Younghwan Kim , Swomitra Kumar Mohanty","doi":"10.1016/j.biosx.2025.100702","DOIUrl":"10.1016/j.biosx.2025.100702","url":null,"abstract":"<div><div>Portable and mobile biosensors are widely applied in point-of-care (POC) diagnostics due to their rapid response and suitability for decentralized testing. While DNA-based probes have been commonly used in electrochemical biosensors owing to their label-free operation, low cost, and sensitivity, their susceptibility to enzymatic degradation and low thermal stability has limited their broader utility. As an alternative, peptide nucleic acid (PNA) probes have gained increasing attention due to their synthetic backbone, which is based on an electrically neutral N-(2-aminoethyl)glycine (AEG) structure. This neutrality confers high resistance to nucleases and polymerases, while enabling stronger and more stable hybridization with negatively charged DNA targets. PNA probes also maintain structural integrity under low ionic strength conditions, improving signal stability compared to conventional DNA probes. These advantages have led to a growing body of research exploring PNA-based biosensors for portable applications. This mini-review surveys recent developments in this area, focusing on the physicochemical properties of PNA and their implications for biosensor design. Future directions for PNA biosensor development are also discussed. Representative studies on electrode architectures and detection strategies are highlighted, demonstrating the potential of PNA-based systems to support next-generation portable diagnostics.</div></div>","PeriodicalId":260,"journal":{"name":"Biosensors and Bioelectronics: X","volume":"27 ","pages":"Article 100702"},"PeriodicalIF":10.61,"publicationDate":"2025-10-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145358739","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-10-15DOI: 10.1016/j.biosx.2025.100701
Ashutosh Kumar , Santosh Kumar , Nikita Mohanta , Siddharth Singh , Manoj K. Pal , Hem Chandra Jha , Mukesh Kumar
Early detection of lung cancer is crucial because of the lower survival rate for improving treatment outcomes. Chip-scale photonic biosensors offer a promising label-free and non-invasive diagnostic approach by analyzing intercellular properties. Here, we demonstrate a chip-scale photonic platform based on semiconductor heterojunctions of n-type ZnO/TiO2 with a comb-like structure to enable label-free detection of lung cancer cells. The lung cancer cells are detected using the engineered structure of the proposed photodetector through distinct fluctuations in the cells' electrical signature. The proposed voltage-controlled device configuration enhances interband transitions within the ZnO/TiO2 depletion region with strong light-matter interaction, particularly in the UV spectrum. The proposed biosensor results in an enhanced photocurrent response in the presence of A549 cells, demonstrating its high sensitivity towards lung cancer detection. The photocurrent in PBS increases from 45 μA to 80 μA when a small concentration of A549 cells (500 cells/μl) is added at a low bias of 1.6 V, demonstrating label-free detection capability. The proposed device with its engineered structure combines ZnO's efficient charge carrier transport with TiO2's proven biocompatibility, enabling sensitive and non-invasive analysis with an additional flexibility of voltage-controlled operation. The demonstrated on-chip biosensor can be a potential candidate for cancer detection, which can enable future integration with compact biosystems.
{"title":"Chip-scale optical detection of lung cancer with engineered photodetector based on distributed semiconductor heterojunctions","authors":"Ashutosh Kumar , Santosh Kumar , Nikita Mohanta , Siddharth Singh , Manoj K. Pal , Hem Chandra Jha , Mukesh Kumar","doi":"10.1016/j.biosx.2025.100701","DOIUrl":"10.1016/j.biosx.2025.100701","url":null,"abstract":"<div><div>Early detection of lung cancer is crucial because of the lower survival rate for improving treatment outcomes. Chip-scale photonic biosensors offer a promising label-free and non-invasive diagnostic approach by analyzing intercellular properties. Here, we demonstrate a chip-scale photonic platform based on semiconductor heterojunctions of n-type ZnO/TiO<sub>2</sub> with a comb-like structure to enable label-free detection of lung cancer cells. The lung cancer cells are detected using the engineered structure of the proposed photodetector through distinct fluctuations in the cells' electrical signature. The proposed voltage-controlled device configuration enhances interband transitions within the ZnO/TiO<sub>2</sub> depletion region with strong light-matter interaction, particularly in the UV spectrum. The proposed biosensor results in an enhanced photocurrent response in the presence of A549 cells, demonstrating its high sensitivity towards lung cancer detection. The photocurrent in PBS increases from 45 μA to 80 μA when a small concentration of A549 cells (500 cells/μl) is added at a low bias of 1.6 V, demonstrating label-free detection capability. The proposed device with its engineered structure combines ZnO's efficient charge carrier transport with TiO<sub>2</sub>'s proven biocompatibility, enabling sensitive and non-invasive analysis with an additional flexibility of voltage-controlled operation. The demonstrated on-chip biosensor can be a potential candidate for cancer detection, which can enable future integration with compact biosystems.</div></div>","PeriodicalId":260,"journal":{"name":"Biosensors and Bioelectronics: X","volume":"27 ","pages":"Article 100701"},"PeriodicalIF":10.61,"publicationDate":"2025-10-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145321015","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-10-14DOI: 10.1016/j.biosx.2025.100700
Roxane Mutschler , Alessandro T. Caputo , Zhong Guo , Yi Jin Liew , Maria Micaela Fiorito , Sophia Newton , Xi Zhang , Nuwan Karunathilaka , Wandy Chan , Karam Kostner , Dariusz Korczyk , John J. Atherton , Andrew J.S. Coates , Chamindie Punyadeera , Kirill Alexandrov , Zhenling Cui
Artificial allosteric protein switches (biosensors) hold the promise to deliver disruptive analytical and diagnostic applications. However, their construction is complicated by the limited availability of selective receptor domains. Here, we report the use of mRNA display to rapidly select FN3con-based binding domains to S100A7 protein - a biomarker of heart failure. The crystal structure of the resulting FN3con binding domain in complex with S100A7 dimer revealed that the binding interface of the dimer is formed by similar, but not identical, side-chain interaction networks. Using medium-throughput functional screening, we tested selected binding domains for compatibility with two protein biosensor architectures. The best biosensor demonstrated a dynamic range of 57-fold and a 1 nM limit of detection and was used to establish a rapid homogeneous assay for quantification of S100A7 in clinical saliva samples. The assay was able to distinguish heart failure patient samples from those of healthy donors. Our results demonstrate that mRNA binding domain development and biosensor prototyping pipelines can deliver practically useful biosensors to potentially any target.
{"title":"Protein biosensors of heart failure biomarker S100A7","authors":"Roxane Mutschler , Alessandro T. Caputo , Zhong Guo , Yi Jin Liew , Maria Micaela Fiorito , Sophia Newton , Xi Zhang , Nuwan Karunathilaka , Wandy Chan , Karam Kostner , Dariusz Korczyk , John J. Atherton , Andrew J.S. Coates , Chamindie Punyadeera , Kirill Alexandrov , Zhenling Cui","doi":"10.1016/j.biosx.2025.100700","DOIUrl":"10.1016/j.biosx.2025.100700","url":null,"abstract":"<div><div>Artificial allosteric protein switches (biosensors) hold the promise to deliver disruptive analytical and diagnostic applications. However, their construction is complicated by the limited availability of selective receptor domains. Here, we report the use of mRNA display to rapidly select FN3con-based binding domains to S100A7 protein - a biomarker of heart failure. The crystal structure of the resulting FN3con binding domain in complex with S100A7 dimer revealed that the binding interface of the dimer is formed by similar, but not identical, side-chain interaction networks. Using medium-throughput functional screening, we tested selected binding domains for compatibility with two protein biosensor architectures. The best biosensor demonstrated a dynamic range of 57-fold and a 1 nM limit of detection and was used to establish a rapid homogeneous assay for quantification of S100A7 in clinical saliva samples. The assay was able to distinguish heart failure patient samples from those of healthy donors. Our results demonstrate that mRNA binding domain development and biosensor prototyping pipelines can deliver practically useful biosensors to potentially any target.</div></div>","PeriodicalId":260,"journal":{"name":"Biosensors and Bioelectronics: X","volume":"27 ","pages":"Article 100700"},"PeriodicalIF":10.61,"publicationDate":"2025-10-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145321386","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-10-10DOI: 10.1016/j.biosx.2025.100698
Lawrence Nsubuga , Tatiana Lisboa Marcondes , Simon Høegh , Horst-Günter Rubahn , Roana de Oliveira Hansen
Electronic nose (e-nose) technologies rely on functional layers to enable selective detection of target analytes. While previous work has focused on improving repeatability through surface treatments and binder placement, challenges in sensitivity have limited the detection of early-stage spoilage in food applications. In this study, we present an approach to enhance the sensitivity of a piezoelectrically driven microcantilever (PD-MC) based e-nose by engineering the sensing material (binder) composition for cadaverine, while optimizing the sensing mechanism and improving surface application capabilities. Cadaverine is a proven biogenic amine associated with the spoilage of meat. The sensing material is synthesized by complexing Nickel with Cyclam in barium hydroxide, forming a square planar [Ni(cyclam)]2+ complex, and modified cyclam with substituted moieties, which forms a viscous glue used as a buffer for the active components and aiding in immobilization on the PD-MC surface. The modified binder formulation is found to enable the detection of cadaverine concentrations as low as 30 μg/kg, allowing for the differentiation between meat freshness on day 1 and day 2. This is a significant improvement over the previously reported detection threshold. Enhanced sensitivity is achieved without compromising repeatability or selectivity, as demonstrated through controlled exposure experiments and resonance frequency analyses. These findings largely advance the development of high-sensitivity, scalable e-nose systems for real-time monitoring of food freshness.
{"title":"High-sensitivity biogenic amine detection via engineered binder formulation in resonant microcantilever gas sensors: A case study of cadaverine","authors":"Lawrence Nsubuga , Tatiana Lisboa Marcondes , Simon Høegh , Horst-Günter Rubahn , Roana de Oliveira Hansen","doi":"10.1016/j.biosx.2025.100698","DOIUrl":"10.1016/j.biosx.2025.100698","url":null,"abstract":"<div><div>Electronic nose (e-nose) technologies rely on functional layers to enable selective detection of target analytes. While previous work has focused on improving repeatability through surface treatments and binder placement, challenges in sensitivity have limited the detection of early-stage spoilage in food applications. In this study, we present an approach to enhance the sensitivity of a piezoelectrically driven microcantilever (PD-MC) based e-nose by engineering the sensing material (binder) composition for cadaverine, while optimizing the sensing mechanism and improving surface application capabilities. Cadaverine is a proven biogenic amine associated with the spoilage of meat. The sensing material is synthesized by complexing Nickel with Cyclam in barium hydroxide, forming a square planar [Ni(cyclam)]<sup>2+</sup> complex, and modified cyclam with substituted moieties, which forms a viscous glue used as a buffer for the active components and aiding in immobilization on the PD-MC surface. The modified binder formulation is found to enable the detection of cadaverine concentrations as low as 30 μg/kg, allowing for the differentiation between meat freshness on day 1 and day 2. This is a significant improvement over the previously reported detection threshold. Enhanced sensitivity is achieved without compromising repeatability or selectivity, as demonstrated through controlled exposure experiments and resonance frequency analyses. These findings largely advance the development of high-sensitivity, scalable e-nose systems for real-time monitoring of food freshness.</div></div>","PeriodicalId":260,"journal":{"name":"Biosensors and Bioelectronics: X","volume":"27 ","pages":"Article 100698"},"PeriodicalIF":10.61,"publicationDate":"2025-10-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145321385","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-10-10DOI: 10.1016/j.biosx.2025.100699
Santiago Botasini , David Zhan , Norman Fischer , Charlotte T. Ravel , Ashley Tien , Maggie R. Grant , Glory Minabou Ndjite , Ty Sopko , Holly Childs , Maryann Greenfield , Christina X. Qian , Kara E. Gardiner , Nayantara M. Anders , Tasnim F. Ullah , Leah T. Redmond , Delaina A. Callaway , Eliya M. Behailu , Grace M. Sarkar , Nakati C. Sany , Margaret Slavin , Brantley Hall
The temporal dynamics of gut microbial metabolism, including how quickly and variably microbes respond to dietary changes, remain largely invisible to current research methods. While measuring metabolic outputs like short-chain fatty acids (SCFAs) in stool or blood provide insights into microbial metabolism, sampling frequency is severely limited, preventing observation of the temporal dynamics of how gut microbes respond to dietary inputs and environmental changes on an hour-by-hour basis. Hydrogen gas, produced by gut microbial metabolism, represents an underutilized biomarker for continuous monitoring of microbial metabolic activity. Following its production, hydrogen is expelled through two major routes: breath and flatus, with flatus containing dramatically higher hydrogen concentrations compared to breath, making it an ideal target for sensitive detection. Currently, no tools exist for continuous, non-invasive monitoring of hydrogen in flatus to track changes in gut microbial metabolism. To address this gap, we developed the Smart Underwear, the first wearable device that continuously measures hydrogen gas expelled in flatus, providing unprecedented temporal resolution of gut microbial activity. In a week-long User Experience Study, the Smart Underwear successfully tracked hydrogen in flatus with participants reporting high comfort and compliance. In a second study, the Smart Underwear accurately detected increased hydrogen production following inulin ingestion with 94.7 % sensitivity in 38 healthy participants, demonstrating its capability to track diet-induced changes in microbial metabolism. This novel platform enables longitudinal studies of microbiome function, capturing both inter-individual differences and intra-individual temporal dynamics, while opening new avenues for investigating diet-microbiome interactions, circadian patterns, and the functional consequences of changes in microbial composition.
{"title":"Smart underwear: A novel wearable for long-term monitoring of gut microbial gas production via flatus","authors":"Santiago Botasini , David Zhan , Norman Fischer , Charlotte T. Ravel , Ashley Tien , Maggie R. Grant , Glory Minabou Ndjite , Ty Sopko , Holly Childs , Maryann Greenfield , Christina X. Qian , Kara E. Gardiner , Nayantara M. Anders , Tasnim F. Ullah , Leah T. Redmond , Delaina A. Callaway , Eliya M. Behailu , Grace M. Sarkar , Nakati C. Sany , Margaret Slavin , Brantley Hall","doi":"10.1016/j.biosx.2025.100699","DOIUrl":"10.1016/j.biosx.2025.100699","url":null,"abstract":"<div><div>The temporal dynamics of gut microbial metabolism, including how quickly and variably microbes respond to dietary changes, remain largely invisible to current research methods. While measuring metabolic outputs like short-chain fatty acids (SCFAs) in stool or blood provide insights into microbial metabolism, sampling frequency is severely limited, preventing observation of the temporal dynamics of how gut microbes respond to dietary inputs and environmental changes on an hour-by-hour basis. Hydrogen gas, produced by gut microbial metabolism, represents an underutilized biomarker for continuous monitoring of microbial metabolic activity. Following its production, hydrogen is expelled through two major routes: breath and flatus, with flatus containing dramatically higher hydrogen concentrations compared to breath, making it an ideal target for sensitive detection. Currently, no tools exist for continuous, non-invasive monitoring of hydrogen in flatus to track changes in gut microbial metabolism. To address this gap, we developed the Smart Underwear, the first wearable device that continuously measures hydrogen gas expelled in flatus, providing unprecedented temporal resolution of gut microbial activity. In a week-long User Experience Study, the Smart Underwear successfully tracked hydrogen in flatus with participants reporting high comfort and compliance. In a second study, the Smart Underwear accurately detected increased hydrogen production following inulin ingestion with 94.7 % sensitivity in 38 healthy participants, demonstrating its capability to track diet-induced changes in microbial metabolism. This novel platform enables longitudinal studies of microbiome function, capturing both inter-individual differences and intra-individual temporal dynamics, while opening new avenues for investigating diet-microbiome interactions, circadian patterns, and the functional consequences of changes in microbial composition.</div></div>","PeriodicalId":260,"journal":{"name":"Biosensors and Bioelectronics: X","volume":"27 ","pages":"Article 100699"},"PeriodicalIF":10.61,"publicationDate":"2025-10-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145321016","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-10-08DOI: 10.1016/j.biosx.2025.100697
Fabian O. Romero-Soto , Masoud Madadelahi , Victor H. Perez-Gonzalez , Sergio O. Martinez-Chapa , Marc J. Madou
Interdigitated electrodes (IDEs) enhance analyte diffusion through overlapping concentration profiles, locally renewing analyte and improving signal response. As the IDE gap decreases, redox amplification (RA)—efficiency of the analyte cycling between electrodes—improves exponentially. However, fabricating sub-micron gaps is costly and complex, limiting point-of-care applicability. To address this, we demonstrated that forced convection, i.e., hydrodynamic flow and mechanical vibration, significantly enhances mass transport and signal response in gold IDEs with 10, 5, and 2 μm gaps. Using methylene blue (MB) and potassium ferricyanide/ferrocyanide as redox probes, we examined flow direction (parallel and cross) and mechanical vibration effects. Under hydrodynamic flow, RA values decreased because convection disrupted lateral diffusion; however, the signal response increased due to enhanced analyte replenishment by mass transport. For MB, RA in cross-flow was direction-dependent: one direction reduced analyte depletion, yielding an 11.9 % higher RA. No significant directional effect was observed for the ferricyanide/ferrocyanide couple. Redox cycling under mechanical vibration across a 10 μm gap IDE increased the signal by 8-fold for MB and 4-fold for the ferricyanide/ferrocyanide couple compared to redox cycling under stagnant conditions. The maximum signal enhancement ratio (SER) obtained for MB (19.1) represents the highest vibration-induced value reported to date. To validate biosensing applicability, dopamine detection with redox cycling under mechanical vibration conditions achieved a detection limit (LOD) of 0.52 μM, nearly sixfold lower than in single-mode under stagnant conditions. These results show that large-gap IDEs without surface modification, combined with external convection, can achieve high RA performance and low LOD with minimal liquid volume (<20 μL). This strategy provides a cost-effective and scalable approach in electrochemical sensors for medical diagnostics and water analysis.
{"title":"High-performance electrochemical sensors: The impact of hydrodynamic flow and vibration on redox amplification","authors":"Fabian O. Romero-Soto , Masoud Madadelahi , Victor H. Perez-Gonzalez , Sergio O. Martinez-Chapa , Marc J. Madou","doi":"10.1016/j.biosx.2025.100697","DOIUrl":"10.1016/j.biosx.2025.100697","url":null,"abstract":"<div><div>Interdigitated electrodes (IDEs) enhance analyte diffusion through overlapping concentration profiles, locally renewing analyte and improving signal response. As the IDE gap decreases, redox amplification (RA)—efficiency of the analyte cycling between electrodes—improves exponentially. However, fabricating sub-micron gaps is costly and complex, limiting point-of-care applicability. To address this, we demonstrated that forced convection, i.e., hydrodynamic flow and mechanical vibration, significantly enhances mass transport and signal response in gold IDEs with 10, 5, and 2 μm gaps. Using methylene blue (MB) and potassium ferricyanide/ferrocyanide as redox probes, we examined flow direction (parallel and cross) and mechanical vibration effects. Under hydrodynamic flow, RA values decreased because convection disrupted lateral diffusion; however, the signal response increased due to enhanced analyte replenishment by mass transport. For MB, RA in cross-flow was direction-dependent: one direction reduced analyte depletion, yielding an 11.9 % higher RA. No significant directional effect was observed for the ferricyanide/ferrocyanide couple. Redox cycling under mechanical vibration across a 10 μm gap IDE increased the signal by 8-fold for MB and 4-fold for the ferricyanide/ferrocyanide couple compared to redox cycling under stagnant conditions. The maximum signal enhancement ratio (SER) obtained for MB (19.1) represents the highest vibration-induced value reported to date. To validate biosensing applicability, dopamine detection with redox cycling under mechanical vibration conditions achieved a detection limit (LOD) of 0.52 μM, nearly sixfold lower than in single-mode under stagnant conditions. These results show that large-gap IDEs without surface modification, combined with external convection, can achieve high RA performance and low LOD with minimal liquid volume (<20 μL). This strategy provides a cost-effective and scalable approach in electrochemical sensors for medical diagnostics and water analysis.</div></div>","PeriodicalId":260,"journal":{"name":"Biosensors and Bioelectronics: X","volume":"27 ","pages":"Article 100697"},"PeriodicalIF":10.61,"publicationDate":"2025-10-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145321384","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-10-07DOI: 10.1016/j.biosx.2025.100696
A. D'Avino , A. Milano , V. Marchesano , B. Guilcapi , D. Sagnelli , M. Rippa , L. Zhou , G. Rossi , L. Consagra , M. Brigotti , S. Morabito , L. Petti
Surface-Enhanced Raman Spectroscopy (SERS) is a highly sensitive technique that enhances Raman signals using plasmonic nanomaterials, enabling the detection of trace biomolecules. Flexible SERS substrates offer advantages such as low cost, adaptability to various surfaces, and reliable performance in complex environments, making them ideal for real-time applications in food safety, environmental monitoring, and diagnostics. In this work, we present a flexible SERS sensor based on Kapton film coated with gold nanoparticles, fabricated through a simple bottom-up method. As a case study, we evaluated, for the first time to the best of our knowledge, its performance in detecting Shiga toxins (Stxs), which are produced by Shiga toxin-producing Escherichia coli (STEC) and are responsible for severe illnesses such as hemorrhagic colitis and hemolytic uremic syndrome. Early and accurate detection of Stxs is critical for outbreak control and timely treatment. We focused on three variants: Shiga toxin 1 (Stx1), Shiga toxin 2 (Stx2), and cleaved Stx2, which are structurally similar but differ in pathogenicity. The SERS spectra collected from each toxin revealed subtle but consistent differences, and Principal Component Analysis (PCA) successfully discriminated between them. Notably, our sensor achieved an outstanding enhancement factor of 7 × 106 and reached an ultra-low limit of detection (LOD) of 15 pM for Stx2 representing, to our knowledge, the lowest LOD reported to date for this toxin using a flexible SERS platform. We also evaluated the LOD in clinically relevant concentrations measured in sera, demonstrating that our system provides a sensitivity suitable for application in real diagnostic settings in the earlier stages of the disease. These results demonstrate the high sensitivity and discriminative power of our sensor, highlighting its strong potential for real-time, on-site monitoring of hazardous biomolecules in fields such as environmental surveillance, food safety, and clinical diagnostics.
{"title":"Flexible gold nanoparticle SERS tape for rapid, label-free and ultrasensitive detection and differentiation of Shiga toxin variants","authors":"A. D'Avino , A. Milano , V. Marchesano , B. Guilcapi , D. Sagnelli , M. Rippa , L. Zhou , G. Rossi , L. Consagra , M. Brigotti , S. Morabito , L. Petti","doi":"10.1016/j.biosx.2025.100696","DOIUrl":"10.1016/j.biosx.2025.100696","url":null,"abstract":"<div><div>Surface-Enhanced Raman Spectroscopy (SERS) is a highly sensitive technique that enhances Raman signals using plasmonic nanomaterials, enabling the detection of trace biomolecules. Flexible SERS substrates offer advantages such as low cost, adaptability to various surfaces, and reliable performance in complex environments, making them ideal for real-time applications in food safety, environmental monitoring, and diagnostics. In this work, we present a flexible SERS sensor based on Kapton film coated with gold nanoparticles, fabricated through a simple bottom-up method. As a case study, we evaluated, for the first time to the best of our knowledge, its performance in detecting Shiga toxins (Stxs), which are produced by Shiga toxin-producing Escherichia coli (STEC) and are responsible for severe illnesses such as hemorrhagic colitis and hemolytic uremic syndrome. Early and accurate detection of Stxs is critical for outbreak control and timely treatment. We focused on three variants: Shiga toxin 1 (Stx1), Shiga toxin 2 (Stx2), and cleaved Stx2, which are structurally similar but differ in pathogenicity. The SERS spectra collected from each toxin revealed subtle but consistent differences, and Principal Component Analysis (PCA) successfully discriminated between them. Notably, our sensor achieved an outstanding enhancement factor of 7 × 10<sup>6</sup> and reached an ultra-low limit of detection (LOD) of 15 pM for Stx2 representing, to our knowledge, the lowest LOD reported to date for this toxin using a flexible SERS platform. We also evaluated the LOD in clinically relevant concentrations measured in sera, demonstrating that our system provides a sensitivity suitable for application in real diagnostic settings in the earlier stages of the disease. These results demonstrate the high sensitivity and discriminative power of our sensor, highlighting its strong potential for real-time, on-site monitoring of hazardous biomolecules in fields such as environmental surveillance, food safety, and clinical diagnostics.</div></div>","PeriodicalId":260,"journal":{"name":"Biosensors and Bioelectronics: X","volume":"27 ","pages":"Article 100696"},"PeriodicalIF":10.61,"publicationDate":"2025-10-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145263113","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Graphene oxide (GO) emerged as a biosensing material due to its patternable features, electron transfer properties, high functionality, and greater surface area that enables sensitive point-of-use applications. This report outlines the design of an electrochemical biosensor composed of a polycarbonate track-etched (PCTE) nano-sieve platform with two silver electrodes, which can detect the surface glycoprotein of the severe acute respiratory syndrome coronavirus 2 (SARS CoV-2), specifically the Spike protein (S-protein), in a rapid and sensitive manner. To fabricate the GO material, we utilized the modified Hummers' method to convert graphite powder. In this study, we covalently immobilized SARS-CoV-2 specific antibodies onto an EDC-NHS functionalized nanosieve platform using two methods i.e., conventional or traditional method and protein-G mediated. The immobilization of these antibodies on the nanosieve platform was achieved through bio-linkage, resulting in specific interactions between the spike protein and the antibodies. These interactions led to a partial blockage of the nanosieve, this led to a considerable decrease in the ionic current for a voltage range of 1.0–2.0 V. The linear range was set between 3.6 mM and 3.6 aM. The detection limit was in nM in traditional method which was notably decreased to fM in protein-G mediated antibodies immobilization. Notably, when testing two non-specific proteins, bovine serum albumin (BSA) and influenza virus, under the same settings, there was no significant change in the current. This nano-biorecognition platform, or nanobiosensor, offers improved stability and higher sensitivity due to the integration of minor GO laminates.
{"title":"Design and fabrication of an electrochemical nano-biosensor for the quick sensing of SARS CoV-2","authors":"Sonali Priyadarshini , Kanchan Karki , Sanjay Kumar , Lakshika Bhandari , Krishna Pal Singh , Narotam Sharma , Anuj Nehra","doi":"10.1016/j.biosx.2025.100695","DOIUrl":"10.1016/j.biosx.2025.100695","url":null,"abstract":"<div><div>Graphene oxide (GO) emerged as a biosensing material due to its patternable features, electron transfer properties, high functionality, and greater surface area that enables sensitive point-of-use applications. This report outlines the design of an electrochemical biosensor composed of a polycarbonate track-etched (PCTE) nano-sieve platform with two silver electrodes, which can detect the surface glycoprotein of the severe acute respiratory syndrome coronavirus 2 (SARS CoV-2), specifically the Spike protein (S-protein), in a rapid and sensitive manner. To fabricate the GO material, we utilized the modified Hummers' method to convert graphite powder. In this study, we covalently immobilized SARS-CoV-2 specific antibodies onto an EDC-NHS functionalized nanosieve platform using two methods i.e., conventional or traditional method and protein-G mediated. The immobilization of these antibodies on the nanosieve platform was achieved through bio-linkage, resulting in specific interactions between the spike protein and the antibodies. These interactions led to a partial blockage of the nanosieve, this led to a considerable decrease in the ionic current for a voltage range of 1.0–2.0 V. The linear range was set between 3.6 mM and 3.6 aM. The detection limit was in nM in traditional method which was notably decreased to fM in protein-G mediated antibodies immobilization. Notably, when testing two non-specific proteins, bovine serum albumin (BSA) and influenza virus, under the same settings, there was no significant change in the current. This nano-biorecognition platform, or nanobiosensor, offers improved stability and higher sensitivity due to the integration of minor GO laminates.</div></div>","PeriodicalId":260,"journal":{"name":"Biosensors and Bioelectronics: X","volume":"27 ","pages":"Article 100695"},"PeriodicalIF":10.61,"publicationDate":"2025-09-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145217678","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-09-25DOI: 10.1016/j.biosx.2025.100693
Marco Cinquino , Suleyman Mahircan Demir , Angela Tafadzwa Shumba , Luca Fachechi , Francesco Rizzi , Antonio Qualtieri , Luigi Patrono , Vincenzo Mariano Mastronardi , Massimo De Vittorio
Monitoring physiological cardiovascular parameters such as heart rate, heart rate variability (HRV), heart sounds, blood pressure wave (BPW), pulse wave velocity (PWV), and cardio-ankle vascular index (CAVI) is crucial for the early diagnosis of cardiovascular diseases. While hospital monitoring devices are consistently reliable, they are often expensive, bulky, and require well-trained personnel. Low-cost, highly accessible, and easy-to-use devices that continuously monitor these parameters are extremely important as they can address these issues, helping individuals to stay informed about their health status. Here is reported a new method for simultaneously measuring cardiovascular bio-indicators by analyzing Ballistocardiogram (BCG), BPW, and heart sound traces, achieved by a single acquisition, exploiting a thin, flexible, bio-compatible, and non-invasive piezoelectric sensor based on a 1 μm thick aluminum nitride film and a flexible 25 μm thick Kapton substrate. A CAVI = 6.8 ± 0.3, and the other 26 parameters are measured from four arterial pulse sites – carotid, brachial, radial, and posterior tibial arteries – providing a comprehensive subject's health profile. The proposed approach offers a non-invasive method for continuous health monitoring, exploiting a bio-compatible, low-cost, and low-power technology that can also be a powerful tool for disease prevention, facilitating personalized medical diagnosis and therapies simultaneously.
{"title":"A novel approach for non-invasive, simultaneous, and realtime monitoring of BCG, BPW, and heart sounds with flexible and bio-compatible piezoelectric AlN sensor","authors":"Marco Cinquino , Suleyman Mahircan Demir , Angela Tafadzwa Shumba , Luca Fachechi , Francesco Rizzi , Antonio Qualtieri , Luigi Patrono , Vincenzo Mariano Mastronardi , Massimo De Vittorio","doi":"10.1016/j.biosx.2025.100693","DOIUrl":"10.1016/j.biosx.2025.100693","url":null,"abstract":"<div><div>Monitoring physiological cardiovascular parameters such as heart rate, heart rate variability (HRV), heart sounds, blood pressure wave (BPW), pulse wave velocity (PWV), and cardio-ankle vascular index (CAVI) is crucial for the early diagnosis of cardiovascular diseases. While hospital monitoring devices are consistently reliable, they are often expensive, bulky, and require well-trained personnel. Low-cost, highly accessible, and easy-to-use devices that continuously monitor these parameters are extremely important as they can address these issues, helping individuals to stay informed about their health status. Here is reported a new method for simultaneously measuring cardiovascular bio-indicators by analyzing Ballistocardiogram (BCG), BPW, and heart sound traces, achieved by a single acquisition, exploiting a thin, flexible, bio-compatible, and non-invasive piezoelectric sensor based on a 1 μm thick aluminum nitride film and a flexible 25 μm thick Kapton substrate. A CAVI = 6.8 ± 0.3, and the other 26 parameters are measured from four arterial pulse sites – carotid, brachial, radial, and posterior tibial arteries – providing a comprehensive subject's health profile. The proposed approach offers a non-invasive method for continuous health monitoring, exploiting a bio-compatible, low-cost, and low-power technology that can also be a powerful tool for disease prevention, facilitating personalized medical diagnosis and therapies simultaneously.</div></div>","PeriodicalId":260,"journal":{"name":"Biosensors and Bioelectronics: X","volume":"27 ","pages":"Article 100693"},"PeriodicalIF":10.61,"publicationDate":"2025-09-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145263112","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-09-25DOI: 10.1016/j.biosx.2025.100691
Caterina Ledda , Helena C. Maltezou , Gaetano Isola , Giuseppe Motta , Carmelina Daniela Anfuso , Claudio Costantino , Venerando Rapisarda
The emergence of SARS-CoV-2 and the seasonal burden of influenza have underscored the urgent need for rapid and decentralized diagnostic tools in healthcare settings. This review explores the role of Point-of-Care (POC) testing in controlling respiratory virus transmission, focusing on its technical foundations, clinical applications, and implementation challenges. A systematic literature screening was conducted across PubMed, Scopus, and Web of Science, prioritizing studies from 2020 onward, to examine the diagnostic performance, use cases, and operational constraints of rapid antigen and molecular POC platforms. Comparative analysis highlights substantial differences in analytical sensitivity, turnaround times, cost-effectiveness, and deployment logistics between isothermal amplification, RT-PCR-based, and immunochromatographic assays. Emerging technologies, including SERS-based biosensors and multiplex portable platforms, are also discussed for their potential to enhance specificity and scalability. A dedicated section addresses real-world barriers such as device cost, personnel training, sample throughput, and regulatory considerations. Figure-based summaries and performance tables are included to assist clinicians and policymakers in selecting appropriate tools. Finally, we propose a strategic framework for integrating POC diagnostics into infection control protocols in hospitals and occupational health services. The findings suggest that when appropriately selected and deployed, POC testing can significantly reduce transmission risk, optimize patient management, and minimize workforce disruption. These outcomes justify broader adoption of POC tools and continued investment in innovation and clinical validation.
SARS-CoV-2的出现和流感的季节性负担突出表明，迫切需要在卫生保健机构中使用快速和分散的诊断工具。本文综述了即时检测（POC）在控制呼吸道病毒传播中的作用，重点介绍了其技术基础、临床应用和实施挑战。在PubMed、Scopus和Web of Science上进行了系统的文献筛选，对2020年以后的研究进行了优先排序，以检查快速抗原和分子POC平台的诊断性能、用例和操作限制。对比分析强调了等温扩增、基于rt - pcr和免疫层析分析在分析灵敏度、周转时间、成本效益和部署后勤方面的实质性差异。新兴技术，包括基于sers的生物传感器和多路便携式平台，也因其增强特异性和可扩展性的潜力而被讨论。一个专门的部分解决了现实世界的障碍，如设备成本、人员培训、样品吞吐量和监管考虑。包括基于数字的摘要和绩效表，以帮助临床医生和决策者选择适当的工具。最后，我们提出了将POC诊断纳入医院和职业卫生服务感染控制协议的战略框架。研究结果表明，如果选择和部署得当，POC检测可以显著降低传播风险，优化患者管理，并最大限度地减少劳动力中断。这些结果证明了更广泛地采用POC工具并继续投资于创新和临床验证。
{"title":"Decoding point-of-care testing: A strategic tool for influenza and SARS-CoV-2 management in healthcare facilities","authors":"Caterina Ledda , Helena C. Maltezou , Gaetano Isola , Giuseppe Motta , Carmelina Daniela Anfuso , Claudio Costantino , Venerando Rapisarda","doi":"10.1016/j.biosx.2025.100691","DOIUrl":"10.1016/j.biosx.2025.100691","url":null,"abstract":"<div><div>The emergence of SARS-CoV-2 and the seasonal burden of influenza have underscored the urgent need for rapid and decentralized diagnostic tools in healthcare settings. This review explores the role of Point-of-Care (POC) testing in controlling respiratory virus transmission, focusing on its technical foundations, clinical applications, and implementation challenges. A systematic literature screening was conducted across PubMed, Scopus, and Web of Science, prioritizing studies from 2020 onward, to examine the diagnostic performance, use cases, and operational constraints of rapid antigen and molecular POC platforms. Comparative analysis highlights substantial differences in analytical sensitivity, turnaround times, cost-effectiveness, and deployment logistics between isothermal amplification, RT-PCR-based, and immunochromatographic assays. Emerging technologies, including SERS-based biosensors and multiplex portable platforms, are also discussed for their potential to enhance specificity and scalability. A dedicated section addresses real-world barriers such as device cost, personnel training, sample throughput, and regulatory considerations. Figure-based summaries and performance tables are included to assist clinicians and policymakers in selecting appropriate tools. Finally, we propose a strategic framework for integrating POC diagnostics into infection control protocols in hospitals and occupational health services. The findings suggest that when appropriately selected and deployed, POC testing can significantly reduce transmission risk, optimize patient management, and minimize workforce disruption. These outcomes justify broader adoption of POC tools and continued investment in innovation and clinical validation.</div></div>","PeriodicalId":260,"journal":{"name":"Biosensors and Bioelectronics: X","volume":"27 ","pages":"Article 100691"},"PeriodicalIF":10.61,"publicationDate":"2025-09-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145263105","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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