Integrated Passive Sensing Chip for Highly Sensitive and Reusable Detection of Differential-Charged Nanoplastics Concentration.

In this work, a new type, highly sensitive, and reusable nanoplastics (NPs) microwave detection method is proposed, which can be used to rapidly analyze NPs with different surface charges and sizes. The effective dielectric constant of NPs varies according to the different concentrations, particle sizes, and surface charges of NPs in aqueous solution. The feasibility of the microwave method for differential-charged NPs detection is verified using a complementary split ring resonator sensor manufactured on a cost-effective printed circuit board, which shows a high sensitivity only for positively charged NPs (PS-NH2) detection. To achieve microwave detection of both positively and negatively charged NPs (PS-SO3H), a microscale spiral-coupled resonator sensing chip is manufactured through integrated passive technology, which demonstrates extremely low detection limits and high sensitivity for both PS-NH2 and PS-SO3H, with different concentrations, particle sizes, and charges. In addition, for NPs solution doped with methyl orange, the device can still perform stable measurements, overcoming the inability of traditional NPs molecular element determination and optical detection methods to detect NPs aqueous solution with organic matter doping and color presence. The proposed microwave detection method could also be extended to sensing detection for detecting other hazardous environmental substances.

Simultaneous Biomechanical and Biochemical Monitoring for Self-Powered Breath Analysis.

The high moisture level of exhaled gases unavoidably limits the sensitivity of breath analysis via wearable bioelectronics. Inspired by pulmonary lobe expansion/contraction observed during respiration, a respiration-driven triboelectric sensor (RTS) was devised for simultaneous respiratory biomechanical monitoring and exhaled acetone concentration analysis. A tin oxide-doped polyethyleneimine membrane was devised to play a dual role as both a triboelectric layer and an acetone sensing material. The prepared RTS exhibited excellent ability in measuring respiratory flow rate (2-8 L/min) and breath frequency (0.33-0.8 Hz). Furthermore, the RTS presented good performance in biochemical acetone sensing (2-10 ppm range at high moisture levels), which was validated via finite element analysis. This work has led to the development of a novel real-time active respiratory monitoring system and strengthened triboelectric-chemisorption coupling sensing mechanism.