Luminescent wearable biosensors based on gold nanocluster networks for "turn-on" detection of Uric acid, glucose and alcohol in sweat

Abstract

From the difficulty of awareness of abnormal concentrations of biochemical indexes in people's daily life come wearable sensing technologies. Recently, luminescent wearable biosensors are emerging with simple fabrication, easy use, cost-effectivity and reliability. But several challenges should be taken up, such as availability of varied analytes, high sensitivity, stability of enzymes, photostability, low signal noises and recyclability of sensors. Here, the Luminescent Wearable Sweat Tape (LWST) biosensor is developed via embedding multi-component nanoprobes onto microwell-patterned paper substrates of hollowed-out double-side tapes. The nanoprobes consist of responsive luminophores, enzyme-loaded gold nanocluster (AuNCs) nano-networks, which are wrapped by the switch, MnO₂ nanosheets. The responsive luminophores are constructed by 3 substitutable components: enzymes (uricase, GOx and alcohol dehydrogenase) for molecular target recognition, glutathione-protected AuNCs (yellow, red and green) for luminescent signal output and polycations PAH for integration. MnO₂ NSs as the switch can quench the emission of the AuNCs but degraded by the reductive product of incorporated enzymes. Thus, targeting analysts (uric acid, glucose and alcohol) can be dose-dependently detected through "turn-on" luminescence approach. After incorporating the nanoprobes into hollow-out tapes, the formed LWST biosensors can detect uric acid, glucose and alcohol in sweat with the help of a smartphone. Subsequently, we primarily apply them into human daily life scenario, sampling from dine parties, and the positive relationships of analyte intakes and the increase of analytes in sweat are significant with individual difference.

Keywords: Gold nanoclusters; Luminescence; Polymer networks; Sweat biomarkers; Wearable biosensor.