Ultrafine Capillary-Tube Triboelectric Nanogenerator as Active Sensor for Microliquid Biological and Chemical Sensing

A practical, highly flexible capillary-tube triboelectric nanogenerator (ct-TENG) is reported as a microfluidic sensor. The ct-TENG is composed of an ultrafine tubular sandwich structure of polytetrafluoroethylene capillary tube, double helix aluminum foil, and silicon rubber hermetic tube. For the first time, microliter sampling (sampling volume, 0.5 µL), nondestructive and highly flexible, is achieved simultaneously for a microliquid sensing device. The self-powered ct-TENG is capable of outputting selectable electrical signals (1.1 V, 10 nA, 0.9 nC) used for sensing a volume of 0.5 µL microliquid due to Maxwell's displacement current generated with energy converted from microliquid flow. It also achieves both total aerobic count monitoring and electrical conductivity (κ) detection. Moreover, the ct-TENG is ultrafine/highly flexible structure and enables its application as a microliter magnitude active sensor for qualitative/quantitative detection. This work provides new opportunities for multifunctional sensing and potential applications in microliquid biological and chemical monitoring/detection technology.