Biosensors and Bioelectronics最新文献

miRNA, the non-coding RNA comprised of about 22 nucleotides, serves as the biomarker in various biomedical scenarios based on different expression level. The more miRNAs are characterized, the more accurate result will be obtained, highlighting the necessary of multiplex miRNA quantification. Although PCR-based methods have been widely applied, the limited specificity and sensitivity restrict their application in liquid biopsy, prenatal diagnosis and forensic identification due to the trace of target and degraded specimen. Despite the higher sensitivity and specificity of loop-mediated isothermal amplification (LAMP), the short fragment renders miRNA detection impossible, let alone multiplex quantification. In this study, a novel strategy for multiplex miRNA quantification is developed based on the response of difunctional molecular beacon to hairpin probe-triggered isothermal amplification. Two hairpin probes are designed to hybridize with target miRNA and fused by ligase, forming a dumbbell structure as the trigger to initiate LAMP. The difunctional molecular beacon, featured with 3'-overhang, serves as loop primer by annealing to the dumbbell structure and participates in amplification. The quencher-fluorophore pair located on molecular beacon is separated through strand displacement, generating fluorescence to monitor amplification of each target for multiplex miRNA quantification. Hairpin probe addresses the incompatibility between template length requirement of LAMP and short fragment of miRNA, even extended cDNA from reverse transcription. Besides, specificity is improved by hairpin probe fusion with single nucleotide distinguishability, which is also not possessed in reverse transcription. The paradigm contains universal hairpin probe and molecular beacon, providing a general platform for multiplex miRNA analysis.

Traditional DNA methylation assays for colon cancer still face challenges of insufficient sensitivity, limited specificity, and low cost-efficiency in clinical samples. Herein, we develop an electrochemiluminescence biosensor based on a dual-enhanced electron transfer mechanism using DNA tetrahedral nanostructure probes for the ultrasensitive detection of methylated DNA related to colon cancer. The DNA tetrahedral structure probe overcomes the shortcomings of poor adaptability caused by the low binding efficiency and high spatial steric hindrance in complex clinical samples. The electrochemiluminescence biosensor uses active-site-rich TiO₂-Ti₃C₂ MXenes@AgNPs hybrid nanocomposites as the electro-active substrate. These nanocomposites exhibited accelerated electron transfer and shortened the reaction paths due to the intrinsic photoelectric activity of TiO₂ and the surface plasmon resonance (SPR) effect between AgNPs and TiO₂. Furthermore, the three-dimensional (3D) self-assembled AuNPs-ABEI nanoluminous spheres substantially improved the luminescence intensity by concentrating more AuNPs to accelerate electron transfer while immobilizing additional ABEI molecules. The dual-enhanced electron transfer strategy significantly accelerated the kinetics of interfacial electron transfer. Metal nanoparticles (such as AgNP, AuNP, and TiO₂) generate SPR-induced local electric fields under electrochemical excitation. The electric fields enhance the electron transfer and amplify the electrochemiluminescence intensity, thereby achieving ultra-sensitive detection of the methylated Septin9 gene with a detection limit as low as 8.2 aM. Clinical sample validation using clinical serum samples from healthy controls (n = 100) and colon cancer patients (n = 100) has shown that the biosensor achieves comparable performance to the gold standard method in terms of both sensitivity and specificity, demonstrating equivalent detection efficacy to pyrosequencing.

Hydrogen peroxide (H₂O₂) serves as a key biomarker of oxidative stress in pathological processes such as cancer and inflammation. However, its in vivo visualization remains challenging due to the lack of sensitive, rapid, and bioorthogonal imaging methods. Here, we present a H₂O₂-activatable CRISPR/Cas12a strategy, termed A-BO-CRISPR, for real-time fluorescence imaging in living systems. This biosensing strategy employs a 4-bromomethylphenylboronic acid pinacol ester-caged DNA activator whose binding to crRNA is initially blocked by steric hindrance, effectively suppressing Cas12a trans-cleavage activity. Upon encountering endogenous H₂O₂, the boronate ester is selectively hydrolyzed, restoring activator/crRNA hybridization and triggering amplified fluorescent signal generation via Cas12a-mediated collateral cleavage of a ssDNA reporter. The system achieves a detection limit of 0.64 μM and responds within minutes, enabling real-time monitoring of H₂O₂ fluxes in living cells and tumor-bearing mice. It exhibits high selectivity and robust stability in complex biological environments. By integrating a chemical gating mechanism with CRISPR-based signal amplification, this work paves the way for potential applications in probing redox biology, imaging-guided diagnostics and therapeutic monitoring.

Luminol remains a foundational electrochemiluminescence (ECL) emitter, yet its performance is intrinsically restricted by slow electron transfer and the short-lived, diffusive nature of oxygen-derived intermediates. These limitations necessitate external coreactants or catalytic additives, obscuring mechanistic interpretation and reducing operational robustness. Here we demonstrate an unimolecular strategy to reorganize oxygen-driven ECL by covalently integrating phenanthroline and luminol through an imine linkage. The resulting π-extended scaffold forms an internal electron-relay pathway that enhances charge transport, promotes oxygen activation and stabilizes the radical intermediates required for light emission. The hybrid produces strong, coreactant-free ECL under air-saturated conditions, with mechanistic studies confirming a coordinated sequence of intramolecular electron flow, superoxide formation and excited-state generation within a confined redox microdomain. As a proof of concept, the emitter enables sensitive and selective detection of glutathione across a wide concentration range (0.5-1000 μM, detection limit 0.479 μM), with predictable quenching behavior that reflects the hybrid's reorganized oxygen-activation pathway. These findings establish a mechanism-guided molecular blueprint for designing next-generation, oxygen-responsive luminophores in which electronic coupling and structural confinement jointly dictate ECL efficiency.

This study reports the development of Activated Biochar Carbon Nanoparticles (ABCN) from rice husk waste via CO₂ laser ablation, acid washing, and thermal activation, creating a porous, conductive nanomaterial. Comprehensive characterization using SEM, DLS, XRD, and FTIR confirmed ABCN's structural properties, with derived nanofluids showing 71 nm average particle size and excellent colloidal stability in DI water. The nanofluid was integrated into a microfluidic pressure sensor using soft lithography, demonstrating piezo-resistive functionality across 337 Pa to 60 kPa with strong linearity/repeatability. The sensor achieved rapid response (∼100ms) and recovery (∼70ms) times, enabling real-time monitoring of physiological signals (pulse waves, respiration) and acoustic discrimination of spoken words. This work establishes ABCN-based microfluidic sensors as promising wearable platforms for healthcare diagnostics, combining sustainable materials with high-performance sensing capabilities. The sensor's multifunctionality, derived from agricultural waste, addresses critical needs for affordable, non-invasive health monitoring solutions while demonstrating novel applications in both physiological and acoustic signal detection. These findings highlight the potential of laser-activated biochar nanomaterials for next-generation biomedical devices.

Coexisting aflatoxin B1 (AFB1) and ochratoxin A (OTA) can produce synergetic toxic effects, particularly carcinogenicity, highlighting the importance of their simultaneous detection. Although homogeneous strategies can avoid cross-interference on the electrode surface during multi-target detection, the complexity of the signal amplification process and background interference remains a challenge. This study integrates an efficient signal amplification strategy and magnetic separation technology into a homogeneous electrochemical strategy for the simultaneous detection of AFB1 and OTA. First, taking advantage of the adsorption of Zr-based metal-organic framework (UiO-66) for electroactive dyes, the aptamer was combined with it via the stirring method, followed by enrichment of neutral red (NR)/methylene blue (MB) to prepare a signal amplification probe. Then, the probe capture was achieved through double-strand hybridization by using complementary DNA (cDNA)-functionalized Fe₃O₄@PtNPs. Once the target was present, the high specificity of the aptamer forced the release of the signal probe. Meanwhile, the external magnet can rapidly remove the background-interfering species that are independent of the target. By ingeniously integrating the advantages of low background and an efficient signal amplification strategy, this method successfully achieved highly sensitive simultaneous detection of AFB1 and OTA. The detection ranges for AFB1 and OTA were 1 pg/mL to 100 ng/mL and 500 fg/mL to 100 ng/mL, with detection limits as low as 0.51 pg/mL and 0.42 pg/mL, respectively. Overall, this strategy represents a satisfactory exploration towards achieving efficient and sensitive strategies for detecting numerous mycotoxins.

Wearable microneedles (MNs) biosensors offer significant potential for minimally invasive biomarker detection in interstitial fluid (ISF). However, suboptimal fluid collection efficiency, dermal irritation due to rigid structural components, and inadequate long-term operational stability collectively represent critical barriers to their clinical translation for early disease diagnosis. Here, we propose a fully integrated dual-extraction-driven flexible microneedles (DFMN) sensor for active detection of melanoma-associated miRNA. The DFMN sensor comprises hydrogel MNs, hollow Au-Ag NPs functionalized flexible electrodes, and a miniaturized wireless module. The synergistic combination of passive diffusion driven by hydrogel MN swelling and active transport via reverse iontophoresis enhanced ISF extraction volume by 1.6-fold within 5 min. This dual-extraction mechanism enabled real-time wireless detection of miRNA-221 with an ultra-low limit of detection (LOD) of 43 aM. Furthermore, to enhance reliability in complex biological environments, an artificial neural network algorithm was implemented, achieving a correlation coefficient (R²) of 0.985. The DFMN sensor holds broad application prospects in interdisciplinary fields such as human-machine interaction, smart healthcare, and artificial intelligence, providing an innovative solution for real-time sensitive detection of wearable flexible sensors.

Pathogens have long presented a significant threat to human lives and environmental security, and the rapid detection of infectious pathogens is therefore vital for mitigating such risks. However, the practical application of biosensors is often hampered by complex sample matrices and limited sensitivity. To address these challenges, we established magnetic nanoparticle (MNP) functionalized with phenylboronic acid (PBA) (MNP-PBA) that efficiently and non-destructively captures Staphylococcus aureus (S. aureus) from complex samples within 20 min, achieving 92.21 % capture rate at 10⁸ CFU/mL. In addition, an aggregation-induced emission luminogen, TTQ-PF₆, was introduced as a detection probe. TTQ-PF₆ exhibits a large Stokes shift (265 nm), intense red fluorescence, and exceptional anti-photobleaching ability-representing a 5.67-fold and 9.40-fold enhancement compared to Rhodamine X, respectively. Moreover, TTQ-PF₆ allows multiple fluorophores to be conjugated to a single DNA strand without the need for chemical reagents. The combination of MNP-PBA and red-emitting TTQ-PF₆ provides strong resistance to matrix interference in bacterial detection, realizing a broad detection linear range for S. aureus from 10² to 10⁷ CFU/mL, with a limit of detection as low as 13.74 CFU/mL. Overall, this work provides a robust and efficient platform for pathogen detection in complex environments.