A Biocompatible and High-Sensitive Epidermal Glucose Biosensor Modified by an Enhanced Catalytic Zwitterionic Hydrogel

Biocompatibility of the human-device interface and high sensitivity are essential for epidermal biosensors. This work reports an epidermal glucose biosensor modified by an enhanced catalytic zwitterionic hydrogel, enabling biocompatible and high-sensitive detection. The biosensor comprises two electrodes for interstitial fluid (ISF) extraction by reverse iontophoresis (RI), two electrodes for electrochemical detection, and a highly biocompatible zwitterionic hydrogel for glucose catalysis and interface to skin. The hydrogel is composed of poly-sulfobetaine methacrylate (PSBMA), carboxylate cellulose nanofiber (CNF-C), Al<sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3+</sup>, platinum nanoparticles (PtNPs), and glucose oxidase (GOx). All of the compositions are highly biocompatible, benefiting for human-device interface and the maintaining of the GOx bioactivity. The hydrogel holds an excellent porous network structure for highly GOx loading, accelerating the catalytic decomposition of the extracted glucose. At the same time, the PtNPs enhance the decomposition rates of the hydrogen peroxide produced from glucose decomposition; and improve the electron transfer rate, finally, enabling high-sensitivity of the biosensor. Finally, the epidermal biosensor was applied to human skin to realize non-invasive continuous blood glucose monitoring.