Pub Date : 2026-02-09DOI: 10.1016/j.snb.2026.139639
Tomotaka Kumagai, Tatum Melati Andini, Hiroshi Sugiyama, Daron M. Standley, Soyoung Park
Fluorescence-coded nucleoside analogues, in which photophysical properties are rationally encoded into the nucleobase scaffold, offer powerful tools for probing nucleic acid structure and function in complex biological systems. However, the development of structurally tunable, environment-sensitive fluorescent nucleosides that retain high biocompatibility and versatility remains limited. To address this, we present a tunable platform of ThexT-based fluorescent nucleosides, developed by introducing electronically distinct donor groups. This modular design enables fine-tuning of their photophysical behavior, resulting in donor-dependent variations in solvatochromism, viscosity sensitivity, and quantum yield—hallmarks of fluorescent molecular rotors. aniThexT and mopThexT were synthesized and site-selectively incorporated into DNA without disrupting base-pairing fidelity or duplex stability, preserving their rotor-like characteristics within oligonucleotide strands. When embedded into the G4-forming aptamer AS1411, these probes exhibited fluorescence turn-on effects upon G4 folding and selective nucleolin binding. This enhancement was further evaluated using gel-shift assays, and live-cell imaging, where ThexT derivatives-labeled AS1411 enabled targeted visualization of nucleolin-overexpressing MDA-MB-231 cancer cells. Collectively, this work showcases our ThexT derivatives as versatile fluorogenic probes with broad applicability in nucleic acid structure analysis, biomolecular interaction mapping, and functional cellular imaging.
{"title":"A Variation in Thiophene-Extended Nucleosides as Microenvironment-Sensitive Fluorescent Probes","authors":"Tomotaka Kumagai, Tatum Melati Andini, Hiroshi Sugiyama, Daron M. Standley, Soyoung Park","doi":"10.1016/j.snb.2026.139639","DOIUrl":"https://doi.org/10.1016/j.snb.2026.139639","url":null,"abstract":"Fluorescence-coded nucleoside analogues, in which photophysical properties are rationally encoded into the nucleobase scaffold, offer powerful tools for probing nucleic acid structure and function in complex biological systems. However, the development of structurally tunable, environment-sensitive fluorescent nucleosides that retain high biocompatibility and versatility remains limited. To address this, we present a tunable platform of <sup><strong>Thex</strong></sup><strong>T</strong>-based fluorescent nucleosides, developed by introducing electronically distinct donor groups. This modular design enables fine-tuning of their photophysical behavior, resulting in donor-dependent variations in solvatochromism, viscosity sensitivity, and quantum yield—hallmarks of fluorescent molecular rotors. <sup><strong>aniThex</strong></sup><strong>T</strong> and <sup><strong>mopThex</strong></sup><strong>T</strong> were synthesized and site-selectively incorporated into DNA without disrupting base-pairing fidelity or duplex stability, preserving their rotor-like characteristics within oligonucleotide strands. When embedded into the G4-forming aptamer AS1411, these probes exhibited fluorescence turn-on effects upon G4 folding and selective nucleolin binding. This enhancement was further evaluated using gel-shift assays, and live-cell imaging, where <sup><strong>Thex</strong></sup><strong>T</strong> derivatives-labeled AS1411 enabled targeted visualization of nucleolin-overexpressing MDA-MB-231 cancer cells. Collectively, this work showcases our <sup><strong>Thex</strong></sup><strong>T</strong> derivatives as versatile fluorogenic probes with broad applicability in nucleic acid structure analysis, biomolecular interaction mapping, and functional cellular imaging.","PeriodicalId":425,"journal":{"name":"Sensors and Actuators B: Chemical","volume":"4 1","pages":""},"PeriodicalIF":8.4,"publicationDate":"2026-02-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146139041","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-02-09DOI: 10.1016/j.snb.2026.139636
Guizhen Luo, Ke Xiao, Cuicui Du, Xiaohua Zhang, Jinhua Chen
Staphylococcus enterotoxin B (SEB), a superantigen secreted by Staphylococcus aureus, is a significant pathogenic factor responsible for foodborne infections and food poisoning. Therefore, the sensitive detection of SEB is crucial and remains challenging. Herein, a dual-mode immunosensor that integrated photoelectrochemical (PEC) and electrochemical (EC) techniques was developed for the highly sensitive analysis of SEB, utilizing multifunctional hemin-loaded covalent organic frameworks (COF@hemin) as a signaling probe capable of both switching photocurrent polarity and generating electrochemical signals. The COF@hemin composite was synthesized by functionalization of COF-V with sulfhydryl groups, enabling efficient immobilization of hemin via a sulfhydryl-ene click reaction. After that, SEB antibody (Ab2) was connected to the COF@hemin composite through amide bonding to form Ab2-COF@hemin. Based on the SEB-mediated specific immune sandwich reaction, Ab2-COF@hemin was captured by a photoactive zinc-based metal-organic framework (Zn-MOF)-modified ITO electrode which was pre-immobilized with primary antibody (Ab1). The introduced COF@hemin not only switched the anodic photocurrent of Zn-MOF/ITO electrode to cathodic photocurrent, but also generated high electrochemical response due to the redox ability of hemin. Thus, the constructed PEC-EC dual-mode sensor enabled sensitive detection of SEB, demonstrating a linear range from 0.1 pg mL-1 to 10 ng mL-1 and a detection limit of 0.03 pg mL-1 in PEC mode, and a linear range from 1 pg mL-1 to 5 ng mL-1 with a detection limit of 0.2 pg mL-1 in EC mode. In addition, the proposed immunosensor demonstrated satisfactory performance in SEB detection in complex samples, indicating its potential applicability in food safety monitoring.
{"title":"Photocurrent-polarity-switching Photoelectrochemical and Electrochemical Dual-Mode Immunosensor for Staphylococcal Enterotoxin B Assay Based on Multifunctional COF@hemin Probe","authors":"Guizhen Luo, Ke Xiao, Cuicui Du, Xiaohua Zhang, Jinhua Chen","doi":"10.1016/j.snb.2026.139636","DOIUrl":"https://doi.org/10.1016/j.snb.2026.139636","url":null,"abstract":"Staphylococcus enterotoxin B (SEB), a superantigen secreted by Staphylococcus aureus, is a significant pathogenic factor responsible for foodborne infections and food poisoning. Therefore, the sensitive detection of SEB is crucial and remains challenging. Herein, a dual-mode immunosensor that integrated photoelectrochemical (PEC) and electrochemical (EC) techniques was developed for the highly sensitive analysis of SEB, utilizing multifunctional hemin-loaded covalent organic frameworks (COF@hemin) as a signaling probe capable of both switching photocurrent polarity and generating electrochemical signals. The COF@hemin composite was synthesized by functionalization of COF-V with sulfhydryl groups, enabling efficient immobilization of hemin via a sulfhydryl-ene click reaction. After that, SEB antibody (Ab2) was connected to the COF@hemin composite through amide bonding to form Ab2-COF@hemin. Based on the SEB-mediated specific immune sandwich reaction, Ab2-COF@hemin was captured by a photoactive zinc-based metal-organic framework (Zn-MOF)-modified ITO electrode which was pre-immobilized with primary antibody (Ab1). The introduced COF@hemin not only switched the anodic photocurrent of Zn-MOF/ITO electrode to cathodic photocurrent, but also generated high electrochemical response due to the redox ability of hemin. Thus, the constructed PEC-EC dual-mode sensor enabled sensitive detection of SEB, demonstrating a linear range from 0.1<!-- --> <!-- -->pg<!-- --> <!-- -->mL<sup>-1</sup> to 10<!-- --> <!-- -->ng<!-- --> <!-- -->mL<sup>-1</sup> and a detection limit of 0.03<!-- --> <!-- -->pg<!-- --> <!-- -->mL<sup>-1</sup> in PEC mode, and a linear range from 1<!-- --> <!-- -->pg<!-- --> <!-- -->mL<sup>-1</sup> to 5<!-- --> <!-- -->ng<!-- --> <!-- -->mL<sup>-1</sup> with a detection limit of 0.2<!-- --> <!-- -->pg<!-- --> <!-- -->mL<sup>-1</sup> in EC mode. In addition, the proposed immunosensor demonstrated satisfactory performance in SEB detection in complex samples, indicating its potential applicability in food safety monitoring.","PeriodicalId":425,"journal":{"name":"Sensors and Actuators B: Chemical","volume":"90 1","pages":""},"PeriodicalIF":8.4,"publicationDate":"2026-02-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146139040","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Salmonella typhimurium (S. typhimurium) is a prominent foodborne pathogen frequently detected in poultry and egg products, posing persistent challenges to food safety. Herein, we present a dual-recognition electrochemical biosensor that integrates aptamers and bacteriophages (phages) for highly sensitive detection of S. typhimurium. Tetrahedral DNA nanostructures (TDNs) incorporating S. typhimurium aptamers were employed to spatially assemble aptamers on the electrode surface, thereby improving capture efficiency. Meanwhile, phages were directionally immobilized on calcined zeolitic imidazolate framework (QZIF-67) nanostructures loaded with methylene blue (MB) via electrostatic adsorption, serving as both biorecognition and signal amplification elements. Upon target recognition, an “aptamer-bacterium-phage” sandwich complex was formed, which brought MB molecules closer to the electrode and significantly enhanced the electrochemical response. The biosensor achieved an ultralow detection limit of 2.6 CFU/mL and demonstrated excellent recovery rates (90.09-108.70%) in spiked chicken and egg samples, confirming its reliability and applicability. This work provides a practical and integrated approach for rapid and ultrasensitive bacteria detection in food safety monitoring.
{"title":"A High-Sensitivity Aptamer-Phage Dual-Recognition Strategy for Electrochemical Detection of Salmonella typhimurium in Poultry","authors":"Yihang Yang, Xinyu Fang, Cong Liu, Shulei Zhang, Zhiyu Yang, Xu Jin, Liling Hao, Fei Xu","doi":"10.1016/j.snb.2026.139632","DOIUrl":"https://doi.org/10.1016/j.snb.2026.139632","url":null,"abstract":"<em>Salmonella typhimurium</em> (<em>S. typhimurium</em>) is a prominent foodborne pathogen frequently detected in poultry and egg products, posing persistent challenges to food safety. Herein, we present a dual-recognition electrochemical biosensor that integrates aptamers and bacteriophages (phages) for highly sensitive detection of <em>S. typhimurium</em>. Tetrahedral DNA nanostructures (TDNs) incorporating <em>S. typhimurium</em> aptamers were employed to spatially assemble aptamers on the electrode surface, thereby improving capture efficiency. Meanwhile, phages were directionally immobilized on calcined zeolitic imidazolate framework (QZIF-67) nanostructures loaded with methylene blue (MB) via electrostatic adsorption, serving as both biorecognition and signal amplification elements. Upon target recognition, an “aptamer-bacterium-phage” sandwich complex was formed, which brought MB molecules closer to the electrode and significantly enhanced the electrochemical response. The biosensor achieved an ultralow detection limit of 2.6 CFU/mL and demonstrated excellent recovery rates (90.09-108.70%) in spiked chicken and egg samples, confirming its reliability and applicability. This work provides a practical and integrated approach for rapid and ultrasensitive bacteria detection in food safety monitoring.","PeriodicalId":425,"journal":{"name":"Sensors and Actuators B: Chemical","volume":"385 1","pages":""},"PeriodicalIF":8.4,"publicationDate":"2026-02-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146139043","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-02-08DOI: 10.1016/j.snb.2026.139633
Lixin Ma, Xiaonan Yang, Chen Wang, Ruiyun Zhou, Zhikun Yang, Li Sun, Zhiming Guo, Jianrong Cai, Xiaobo Zou
Imidacloprid, a neonicotinoid pesticide commonly found in fruits and vegetables, poses a health hazard when present in excessive residues. This paper designs a terahertz metamaterial sensor based on quasi-bound state in the continuum (QBIC) resonances, achieved by a structure consisting of an external square open-ring and an internal dual-rod structure. Compared with individual components, the coupled meta-atomic array formed by the dual-rod and the open-ring has a stronger electric field intensity. Besides, the effective sensing area of this coupled structure is more than 2.5 times that of the two individual components combined, demonstrating a synergistic “1 + 1 > 2” effect. By adjusting the rod lengths of the dual-rod, a metamaterial exhibiting QBIC resonance at 0.89 THz was obtained, aligning with the absorption peak of imidacloprid and thereby enhancing detection sensitivity. Experimental results show that the QBIC metamaterial sensor exhibits excellent performance, with a linear range of 0.1 mg/kg–1000 mg/kg and a calculated limit of detection of 0.072 mg/kg. Additionally, in spiked orange samples, recovery rates ranged from 92.2% to 104.19%, with no significant difference from high-performance liquid chromatography results. These findings provide a novel strategy for sensitive terahertz detection of imidacloprid pesticide in real samples.
{"title":"Quasi-bound states in the continuum empowered terahertz metamaterial sensor for imidacloprid detection in fruits","authors":"Lixin Ma, Xiaonan Yang, Chen Wang, Ruiyun Zhou, Zhikun Yang, Li Sun, Zhiming Guo, Jianrong Cai, Xiaobo Zou","doi":"10.1016/j.snb.2026.139633","DOIUrl":"https://doi.org/10.1016/j.snb.2026.139633","url":null,"abstract":"Imidacloprid, a neonicotinoid pesticide commonly found in fruits and vegetables, poses a health hazard when present in excessive residues. This paper designs a terahertz metamaterial sensor based on quasi-bound state in the continuum (QBIC) resonances, achieved by a structure consisting of an external square open-ring and an internal dual-rod structure. Compared with individual components, the coupled meta-atomic array formed by the dual-rod and the open-ring has a stronger electric field intensity. Besides, the effective sensing area of this coupled structure is more than 2.5 times that of the two individual components combined, demonstrating a synergistic “1 + 1 > 2” effect. By adjusting the rod lengths of the dual-rod, a metamaterial exhibiting QBIC resonance at 0.89<!-- --> <!-- -->THz was obtained, aligning with the absorption peak of imidacloprid and thereby enhancing detection sensitivity. Experimental results show that the QBIC metamaterial sensor exhibits excellent performance, with a linear range of 0.1<!-- --> <!-- -->mg/kg–1000<!-- --> <!-- -->mg/kg and a calculated limit of detection of 0.072<!-- --> <!-- -->mg/kg. Additionally, in spiked orange samples, recovery rates ranged from 92.2% to 104.19%, with no significant difference from high-performance liquid chromatography results. These findings provide a novel strategy for sensitive terahertz detection of imidacloprid pesticide in real samples.","PeriodicalId":425,"journal":{"name":"Sensors and Actuators B: Chemical","volume":"92 1","pages":""},"PeriodicalIF":8.4,"publicationDate":"2026-02-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146139042","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-02-07DOI: 10.1016/j.snb.2026.139621
Sihui Wang, Feng Liu, Meng Sun, Hongchun Gu, Lei Yang, Xun Feng, Yang Chen
Hydrogen peroxide (H₂O₂) in skin tissue serves as a critical biomarker for oxidative stress and physiological status, yet its precise in situ monitoring remains challenging due to the lack of non-invasive, real-time sensing platforms. Herein, we presented a smartphone-assisted biosensing system based on a nanozyme-integrated hydrogel microneedle patch for on-site and quantitative detection of cutaneous H₂O₂. The sensing platform incorporated a palladium-embedded metal-organic framework (Pd-PCN) with enhanced peroxidase-like activity, which was co-immobilized with a chromogenic substrate in a polymeric composite hydrogel microneedle array. This composite matrix maintained structural integrity and biocompatibility during short-term skin application while providing an aqueous microenvironment favorable for nanozyme-catalyzed reactions. Upon insertion into the skin, H₂O₂ from interstitial fluid would diffuse into the microneedle and trigger a colorimetric reaction. The resulting color intensity could be quantitatively captured via smartphone-based RGB analysis. The system demonstrated a wide linear detection range (5~100 µM), a low detection limit (1.53 µM), high reproducibility (RSD < 5%), and negligible interference from common biological substances. Confocal imaging and mechanical testing further confirm the structural stability and skin-penetration capability of the microneedle under operational conditions. This work established a reliable, minimally invasive, and user-friendly platform for continuous monitoring of oxidative biomarkers in skin, paving the way for personalized dermatological care and point-of-care diagnostics.
{"title":"A Session-Lasting Biostable and Biocompatible Hydrogel Microneedle Patch for Nanozyme-Mediated On-Site and Smartphone-Based Quantification of Skin H₂O₂","authors":"Sihui Wang, Feng Liu, Meng Sun, Hongchun Gu, Lei Yang, Xun Feng, Yang Chen","doi":"10.1016/j.snb.2026.139621","DOIUrl":"https://doi.org/10.1016/j.snb.2026.139621","url":null,"abstract":"Hydrogen peroxide (H₂O₂) in skin tissue serves as a critical biomarker for oxidative stress and physiological status, yet its precise in situ monitoring remains challenging due to the lack of non-invasive, real-time sensing platforms. Herein, we presented a smartphone-assisted biosensing system based on a nanozyme-integrated hydrogel microneedle patch for on-site and quantitative detection of cutaneous H₂O₂. The sensing platform incorporated a palladium-embedded metal-organic framework (Pd-PCN) with enhanced peroxidase-like activity, which was co-immobilized with a chromogenic substrate in a polymeric composite hydrogel microneedle array. This composite matrix maintained structural integrity and biocompatibility during short-term skin application while providing an aqueous microenvironment favorable for nanozyme-catalyzed reactions. Upon insertion into the skin, H₂O₂ from interstitial fluid would diffuse into the microneedle and trigger a colorimetric reaction. The resulting color intensity could be quantitatively captured via smartphone-based RGB analysis. The system demonstrated a wide linear detection range (5~100<!-- --> <!-- -->µM), a low detection limit (1.53<!-- --> <!-- -->µM), high reproducibility (RSD < 5%), and negligible interference from common biological substances. Confocal imaging and mechanical testing further confirm the structural stability and skin-penetration capability of the microneedle under operational conditions. This work established a reliable, minimally invasive, and user-friendly platform for continuous monitoring of oxidative biomarkers in skin, paving the way for personalized dermatological care and point-of-care diagnostics.","PeriodicalId":425,"journal":{"name":"Sensors and Actuators B: Chemical","volume":"38 1","pages":""},"PeriodicalIF":8.4,"publicationDate":"2026-02-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146129714","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-02-06DOI: 10.1016/j.snb.2026.139585
Ehren M. Dixon, Lorraine C. Nagle, James F. Rohan
To address the stability and cost limitations of enzymatic glucose sensors, this work details the use of nanoporous copper (NPC) modified microdisc array (MDA) sensors for non-enzymatic glucose detection, with a focus on bovine health monitoring. Electrochemical analysis in 0.1 M NaOH, using cyclic voltammetry (CV) and chronoamperometry (CA), demonstrated excellent sensor performance. The device demonstrated a wide linear detection range (0.01 – 4.0 mM, R2>0.99) and a 4 µM limit of detection (LOD). It achieved high sensitivities of 14.87 and 9.87 µA µM-1 cm-2 across its low-concentration and full linear detection ranges, respectively. The sensor showed high selectivity, with minimal interference from common analytes in saliva and blood, and ageing studies revealed stable performance for up to 56 days when stored in acetone. Successful validation in artificial saliva confirmed the sensor's applicability for direct biofluid analysis. These findings establish NPC-modified MDAs as a robust, cost-effective, and promising platform for glucose monitoring in complex biofluids, particularly for veterinary diagnostics and agri-tech applications.
{"title":"Nanoporous copper microdisc arrays for non-enzymatic detection of glucose in aqueous and saliva solutions","authors":"Ehren M. Dixon, Lorraine C. Nagle, James F. Rohan","doi":"10.1016/j.snb.2026.139585","DOIUrl":"https://doi.org/10.1016/j.snb.2026.139585","url":null,"abstract":"To address the stability and cost limitations of enzymatic glucose sensors, this work details the use of nanoporous copper (NPC) modified microdisc array (MDA) sensors for non-enzymatic glucose detection, with a focus on bovine health monitoring. Electrochemical analysis in 0.1<!-- --> <!-- -->M NaOH, using cyclic voltammetry (CV) and chronoamperometry (CA), demonstrated excellent sensor performance. The device demonstrated a wide linear detection range (0.01 – 4.0<!-- --> <!-- -->mM, R<sup>2</sup>>0.99) and a 4<!-- --> <!-- -->µM limit of detection (LOD). It achieved high sensitivities of 14.87 and 9.87<!-- --> <!-- -->µA<!-- --> <!-- -->µM<sup>-1</sup> cm<sup>-2</sup> across its low-concentration and full linear detection ranges, respectively. The sensor showed high selectivity, with minimal interference from common analytes in saliva and blood, and ageing studies revealed stable performance for up to 56 days when stored in acetone. Successful validation in artificial saliva confirmed the sensor's applicability for direct biofluid analysis. These findings establish NPC-modified MDAs as a robust, cost-effective, and promising platform for glucose monitoring in complex biofluids, particularly for veterinary diagnostics and agri-tech applications.","PeriodicalId":425,"journal":{"name":"Sensors and Actuators B: Chemical","volume":"177 1","pages":""},"PeriodicalIF":8.4,"publicationDate":"2026-02-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146129715","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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