The Polymer Society of Korea

Abstract

Molecular tracing of ultralow-volume biofluids is essential for precise diagnostics, but integrating optical nanosensors into simple devices that stably capture such fluids from rough, dynamic biosurfaces remains challenging. Here, we present a bioinspired 3D microstructured patch monolithically integrated with optical nanosensors (3D MIN) for real-time spatiotemporal molecular tracing of nanoliter-scale fluids. Inspired by tree frog toe pads, the patch uses soft hexagonally arranged pillars and microchannels to achieve conformal adhesion and controlled fluid capture. Near-infrared fluorescent single-walled carbon nanotube nanosensors embedded in a hydrogel were mechanically integrated within a single elastomer layer, enabling simultaneous fluid capture and sensing. The 3D MIN achieves stable adhesion on wet biosurfaces and enables real-time molecular tracing of human sweat with low-volume analysis (≥75 nL) within 45 s, without exercise or iontophoresis.