Biosensors and Bioelectronics最新文献

Plasmonic photothermal polymerase chain reaction (PPT-PCR) is a nucleic acid amplification technique that utilizes the localized surface plasmon resonance effect of plasmonic nanomaterials under the irradiation of light with specific wavelengths to achieve rapid thermal cycling. PPT-PCR is considered as a next-generation PCR technique due to the potential to be applied to the development of point-of-care diagnostics and the fast, sensitive and accurate detection performance. In this study, we present PHANTOM, a proof-of-concept system that functionally integrates plasmonic photothermal PCR, magnetic nanoparticle removal, and swCNT-FET-based label-free electrical readout for rapid molecular diagnostics. The swCNT-FET sensor exhibits high sensitivity, capable of detecting low concentrations of target nucleic acids within minutes after PPT-PCR amplification. Besides, to improve the specificity of the assay, we introduce a hairpin structured primer to generate amplicons with an external single-strand tail that can hybridize with probes modified on the swCNT-FET sensor. With this design, an estimated limit of detection of 1.5 aM (experimentally validated down to 10 aM) was achieved within 20 min.

Real-time monitoring in organ-on-a-chip (OoC) systems is critical for capturing dynamic drug responses, yet standard gold (Au) electrodes utilized in electrical cell-substrate impedance sensing (ECIS) suffer from opacity, high cost, and poor reusability. Here, we report a transparent, robust, and reusable sensing interface based on iridium oxide-modified fluorine-doped tin oxide (IrOx@FTO). By electrodepositing nanostructured IrOx onto FTO, we exploited its pseudocapacitive properties to significantly improve interfacial properties, enhancing sensitivity while preserving optical clarity. We integrated these electrodes into a 128-channel high-throughput platform to monitor HaCaT keratinocytes. The system successfully resolved acute surfactant-induced barrier disruption and differentiated dose-dependent cytotoxic responses to doxorubicin (DOX) with higher precision than bare FTO. Crucially, cycling tests involving repeated culture and cleaning revealed that IrOx@FTO maintains exceptional baseline stability, significantly outperforming gold electrodes which exhibited severe degradation and delamination. This work establishes a scalable, optically compatible, and cost-effective strategy for long-term, multi-modal monitoring in advanced microphysiological systems.

Electrochemical aptamer-based (E-AB) microneedle (MN) sensors offer a promising route for continuous monitoring of endogenous biomarkers. However, long-term operation is often limited by signal attenuation arising from surface biofouling, aptamer detachment, and redox label degradation. Here, we investigated the origin of signal drift by monitoring changes in the peak current (I_P) of the redox label during prolonged square-wave voltammetry (SWV) operation in PBS, serum, and artificial ISF. To address this drift, we introduced a dual-frequency ratiometric approach based on the ratio between the I_P measured at frequencies showing maximum (F_max) and minimum (F_min) responses. Prolonged SWV measurements in PBS, where biofouling is negligible, showed a gradual decrease in I_P, and cyclic voltammetry measurements obtained before and after SWV operation confirmed a decrease in the MB faradaic current. These results suggest that SWV-induced aptamer detachment and/or MB degradation are major source of intrinsic signal drift. In serum and artificial ISF, this drift was further exacerbated by biofouling, resulting in an approximately 30% decrease in I_P measured at F_max and F_min (IF_max and IF_min) over 48 h. In contrast, the ratiometric signal (I_R = IF_max/IF_min), remained stable because similar signal drift in IF_max and IF_min was effectively compensated. In addition, the ratiometric approach reduced sensor-to-sensor variation, enabling reliable continuous cortisol monitoring with quantified concentrations that closely matched the applied levels, whereas IF_max-based quantification resulted in large deviations. These findings establish dual-frequency ratiometric E-AB MN sensors as a reliable platform for stable and accurate continuous biomarker monitoring in complex biological fluids.

The global rise in waterborne viral infections has created an urgent need for portable, highly efficient environmental virus detection technologies. CRISPR-based nucleic acid detection coupled with isothermal amplification (e.g., Recombinase Polymerase Amplification, RPA) shows great promise for field applications. However, most reported designs fail to achieve the single-molecule sensitivity, which significantly limits their practical applications. To bridge the gap, we proposed a rational design strategy for the RPA primer and the CRISPR-Cas13a crRNA, suggesting that sensitivity can be enhanced by simplifying the secondary structure of the crRNA spacer region. Subsequently, we established a portable, one-tube CRISPR-Cas13a bioassay to detect two major waterborne viruses, achieving ultrasensitive detection limits of 5/8 aM for norovirus and 2/3 aM for rotavirus within 40 min. Thereafter, seasonal sampling across different treatment stages of a drinking water treatment plant was conducted, and water samples were analyzed using the one-tube CRISPR-Cas13a bioassay in comparison with qPCR and dPCR, revealing a positive detection rate of 15.79% (6/38) for the one-tube CRISPR-Cas13a bioassay, 18.42% (7/38) for qPCR, and 15.79% (6/38) for dPCR. The assay's modular design allows for broad applicability to other pathogens by simply modifying the target nucleic acid sequence, offering high sensitivity and specificity. This innovation paves the way for deployable point-of-care testing and large-scale spatiotemporal virus monitoring.

This research addresses the challenge of real-time monitoring of the neurotransmitter serotonin (5-HT), a key chemical messenger in the brain whose dynamics are important for understanding neurological disorders. While electrochemical methods are promising for such real-time detection, existing approaches face limitations in maintaining stable performance in physiological settings and achieving precise spatiotemporal measurements. To overcome these barriers, two electrochemical systems were developed: one for monitoring 5-HT secretion from cells and another for tracking 5-HT in the mouse brain. By enhancing electrodes with specific nanocomposites to improve sensitivity and selectivity, the cell system successfully analyzed real-time 5-HT secretion dynamics from rat insulinoma cells with performance comparable to standard methods. The neural interface system effectively tracked 5-HT fluctuations across multiple brain regions in living mice and detected changes induced by external interventions. These platforms enable real-time tracking of 5-HT dynamics both in cells and in living organisms, demonstrating significant potential for studies requiring real-time neurotransmitter monitoring.

This study developed a novel integrated self-powered biosensor for non-invasive auxiliary detection of pediatric asthma-associated miRNA-155. A flexible self-supporting electrode based on a propylene carbonate-PVDF-HFP/MXene composite was developed and implemented in an enzymatic biofuel cell self-powered sensing system. PVDF-HFP displayed excellent chemical stability and strong film-forming ability and MXene worked as electroactive materials in the self-supporting electrode substrate. The anode of the self-powered biosensor was prepared with Au NPs-decorated cobalt-nickel layered double hydroxide, which effectively enhanced electron transfer between enzymes and electrode to improve power output. Meanwhile, the cathode was designed based on [Ru(NH₃)₆]³⁺ as efficient electron acceptors. As a result, the glucose oxidation reaction at the anode and the reduction of [Ru(NH₃)₆]³⁺ at the cathode generated a measurable open-circuit voltage (E^OCV), which was real-time recorded through smartphone integration. The development of self-powered biosensor overcame the limitations of the low power output, functional layer detachment, and active site deactivation. The established integrated self-powered biosensing system successfully quantified salivary exosomal miRNA-155 across a broad concentration range (0.001-10,000 pM) with a detection limit of 0.21 fM. This work constructed a robust and portable platform suitable for non-invasive auxiliary detection of pediatric asthma, demonstrating promising applications in liquid biopsy.

Sensor arrays perform well in distinguishing subtle changes induced by structurally similar multi-target analytes in complex systems. However, the construction of most sensor arrays requires multiple receptors and sensing units, increasing detection complexity. Here, we developed Co₃O₄@Bi nanozymes with a Co-O-Bi interfacial structure, which is devoted to the construction of a single-receptor-single-reaction-unit multichannel sensor array. The Co-O-Bi interfaces facilitate electron transfer from Co to O and then to Bi and weaken the oxygen adsorption capacity. Compared to the Co₃O₄ nanozymes with repetitive metal Co-O-Co structural units, the resultant Co₃O₄@Bi nanozymes show a 3.6-fold enhancement in peroxidase-like activity, of which the oxidase-like performance exhibits a decline. As a result, the catalytic activity and selectivity of the Co₃O₄@Bi nanozymes were improved by introducing Co-O-Bi interfacial structures. Taking Co₃O₄@Bi as a single receptor and a typical chromogenic reaction as the single reaction unit, the sensor array was established and displayed three distinct characteristic peaks. Based on the different inhibition effects of various pesticides on the activity of Co₃O₄@Bi nanozyme, the characteristic peaks act as multiple signal channels, enabling the 100% discrimination of five pesticides during the combined use of multiple pesticides. In addition, the colorimetric sensor array can accurately identify the target pesticides with good selectivity and anti-interference capability. This work not only offers a new feasible strategy for the design of nanozymes with an interfacial structure but also addresses the reliance of traditional sensor arrays on multiple receptors and units.

Non-invasive wearable biopotential interfaces (WBIs), devices that enable recording of electrical signals from the body's surface, depend on electrodes that form a low impedance interface with the skin. Existing electrodes are often bulky, uncomfortable, slow to stabilize, and socially unacceptable due to their conspicuous appearance, or require complex conductive materials and fabrication processes. Here, we show that thin films of poly(vinyl alcohol) (PVA), a low-cost, transparent, electronically insulating biodegradable thermoplastic, can be used as a discreet, high-performance electrode when exposed to a water-based ionic gel. Water plasticizes PVA and makes it mechanically skin-like. Plasticized PVA also becomes ionically conductive to serve as an electrode that conforms to the skin to enable efficient ion transport at the skin's interface upon application, yielding 13× lower resistance than when the same gel is used with a plastic backing. This eliminates the stabilization delay of conventional wet or semi-wet electrodes, leading to a similar level of performance when compared to benchmark Ag/AgCl semi-wet electrodes for electrocardiography and electromyography, enabling the implementation of a wireless gesture recognition interface. Signal quality is maintained or improved over multi-hour recordings, and artificial sweat can replace the ionic gel to yield a comparable skin-electrode impedance. These results establish biodegradable thermoplastics as a scalable path towards socially acceptable, high-performance WBIs.