Talanta最新文献

The label-free detection and analysis of cancer cells using portable biosensing devices is crucial and promising. In this study, a novel reusable biosensing platform with a microfluidic-like based on terahertz plasmonic metasurfaces utilizing graphene integrated with an all-silicon groove for detecting liquid live cancer cells was developed. The proposed biosensor platform stands out because it can differentiate between the concentrations of three types of cancer cells by monitoring changes in resonance intensity and phase difference. The minimum concentration for identification was reduced to as low as 5 × 10⁴ cells/mL. We effectively constructed two-dimensional optical intensity cards using continuous wavelet transforms, which presented a more accurate approach for the recognition and determination of the three types of cancer cells. Our proposed biosensors show great potential for the determination and recognition of label-free cancer cells in aqueous environments as alternatives to non-immune biosensing technology.

While numerous needle-based continuous glucose monitoring (CGM) devices have been available today, the insufficient enzyme immobilization on monitoring sensor severely limited the detection sensitivity of CGM devices. This manuscript describes here a high-sensitivity continuous glucose sensor (CGS) by engineering a porous 3D cellulose/carbon nanotube (CNT) network on the working electrode, which subcutaneously increases the detection enzyme capacity and thus significantly enhances the signal intensity and sensitivity. Furthermore, a tapered needle made of soft resin is engraved into three distinct microgrooves where the glucose oxidase (GOD)-modified working electrode, Pt-modified counter electrode, and Ag/AgCl-modified reference electrode are separately constructed inside the microgrooves. Moreover, a miniature potentiostat tailored for signal acquisition, processing, and transmission is engineered. After incorporated with a wireless circuit, the proposed CGS achieves continuous glucose monitoring in interstitial fluid with a surprising sensitivity of 9.15 μA/mM/cm², as well as maintaining functionality for a period of up to 9 days in live rats. This work provides the public a high-sensitivity continuous glucose monitoring device.

This study presents a gas chromatographic detector using alternating current (AC) discharged in air to generate μ-arc at atmosphereic pressure. This air-based μ-arc emission detector (μ-AED) was assembled by two stainless-steel syringe needles inside a quartz tube. The length of μ-arc (i.e., distance of discharge) measures 550 μm. The organic compounds with various functional groups were chromatographically separated and fed into the μ-AED. The intensity changes in the emission spectrum were recorded as these compounds passing through the μ-arc. When organic compounds pass through the μ-arc, the changes in emission intensity could go either increase or decrease depending on the input power and underlying mechanisms. It was found that when operating the μ-arc at relatively low power, organic samples present as negative peaks, and better S/N ratio were obtained. The detection limits (3σ/s) range from 209 pg for n-butyl acetate to 552 pg for 1-chloropentane. A selectivity study reveals that μ-AED is more sensitive to oxygen-containing and aromatic compounds. The μ-AED developed in this study demonstrates the simplest design with reasonable miniaturization. The direct discharge in air makes this μ-AED suitable for future application with μ-GC which uses scrubbed air as carrier gas and eliminates bulky gas cylinders.