ACS Sensors最新文献

Pathogenic bacterial infections pose a significant threat to human life, health, and socioeconomic development, with those arising from Escherichia coli (E. coli) O157:H7 being particularly concerning. Herein, customized aggregation-induced emission luminogens (AIEgen)-based signaling tags (TPA-galactose) were combined with a microfluidic chip for the determination of E. coli O157:H7. TPA-galactose undergoes hydrolysis by the β-galactosidase, resulting in the formation of highly fluorescent TPA–OH with AIE characteristics. Phages covalently bound to the surface of magnetic beads specifically capture and lyse E. coli O157:H7, releasing endogenous β-galactosidase, and the fluorescence intensity of TPA–OH facilitates the determination of E. coli O157:H7. The microfluidic chip process achieves a sensitivity of 45 CFU/mL in 45 min, requiring no DNA extraction or amplification, utilizing minimal sample volume, and enabling accurate one-stop quantification of live E. coli O157:H7. This strategy enables the rapid on-site determination of E. coli O157:H7 in environmental, food, and clinical samples, significantly enhancing public health and safety.

Timely and accurate detection of H₂S is crucial for preventing serious health issues in both humans and livestock upon exposure. However, metal-oxide-based H₂S sensors often suffer from mediocre sensitivity, poor selectivity, or long response/recovery time. Here, an atomic Ru species-driven SnO₂-based sensor is fabricated to realize highly sensitive and selective detection of H₂S at the parts per billion level as low as 100 ppb. The sensor shows a high sensing response (R_air/R_gas = 310.1) and an ultrafast response time (less than 1 s) to 20 ppm H₂S at an operating temperature of 160 °C. Operando SR-FTIR spectroscopic characterizations and DFT calculations prove that the superior sensing properties can be mainly attributed to the driven effect of atomic Ru species on the formation of surface-adsorbed oxygen species on the surface of SnO₂, which provides more active sites and enhances the sensing performance of SnO₂ for H₂S. Furthermore, a lab-made wireless portable H₂S monitoring system is developed to rapidly detect the H₂S for early warning, suggesting the potential application of the fabricated H₂S sensor and monitoring system. This work provides a novel approach for fabricating a highly sensitive and selective gas sensor driven by atomic metal species loaded on metal-oxide semiconductors.

Due to fabrication variation (i.e., device-to-device differences in the total number of probes immobilized on their electrode), electrochemical aptamer-based (EAB) sensors generally require calibration, reducing their convenience. In response, here, we describe an approach for achieving calibration-free EAB measurement relying on the differential electron transfer kinetics between target-bound and -unbound states using a square wave voltammetry technique. Specifically, by adjusting the amplitude and frequency of the potential wave, we generate a voltammetric output with two distinct current peaks, which are representative of signals probed from different electron transfer kinetics. The ratio of these two peaks provides a means of correcting the sensor-to-sensor fabrication variation. Using this approach, we demonstrate accurate, calibration-free measurements of multiple small molecules (e.g., kanamycin, ATP, and doxorubicin) and proteins (e.g., thrombin) in whole blood.

Malondialdehyde (MDA) serves as a pivotal indicator to estimate the lipid peroxidation status and as a biomarker for the assessment of oxidative stress and screening of disease by people excretion. However, most of the existing analytical methods for MDA suffer from complicated derivation, leading to poor accuracy and inconvenience. In this work, the guanidinium-functionalized covalent organic framework (COF) was delicacy-designed and used to tune the modular structure by the building blocks with condensation, phototriggered click reaction, and further guanidylation process. A methoxy-group-containing linker in the skeleton was adopted to form lone-pair delocalized oxygen atoms, trigger the resonance effect, attenuate the polarization of the C═N bond linkages, and weaken the interlayer repulsion, supporting the stability of the guest gating COF. The available guanidino groups grew from the ordered pore walls of the COF and served as the customized talon with an enhanced interaction site density to rapidly grab the target guest by charge-assisted strong hydrogen bonds and electrostatic attraction forces. This distinctive feature significantly bolstered sensitive signal transduction, enabling rapid MDA sensing (within 120 s) without derivation treatment, and achieved a calculated limit of detection (LOD) as low as 0.08 μM. With the accessible image-data transmission process, the portable dual-channel sensing platform achieved sensitive and accurate MDA monitoring.