In Vitro Detection of Lactate and Uric Acid Based on Adaptive Graphene Oxide Membranes

In vitro detection of small molecules in the human circulatory system contributes a lot to prompt personalized healthcare and early disease diagnose. The precise detection requires to select target molecules for real-time noninvasive identifications, which remains a challenge derived from the lack of both molecule-sieving techniques and rapid detection tools. Herein, positively charged polymer chains into graphene oxide membranes are seeded to tune their interlayer spacing precisely and persistently within a range of 8.67-13.75 Å. The adaptive yet stable nanocapillaries allow membranes to sieve small molecules with fitted sizes, for example, salts and biomarkers. The molecule-sieving membranes with organic electrochemical transistors, further achieving an in vitro detection of lactate and uric acid with a high accuracy, are coupled. Based on this finding, a wearable sweat lactate rapid test kit, which detects sweat lactate secreted from human body within a few minutes, is demonstrated.