A HYDROGEL MICRONEEDLE INTEGRATED APTAMER-BASED ELECTROCHEMICAL SENSOR FOR GLUCOSE AND LACTATE MONITORING IN LIVE ANIMALS

Transdermal biosensing that interrogates skin interstitial fluid (ISF) for biomarker measurements has great potential to revolutionize the diabetic healthcare system as it enables a facile and dynamic approach to tracking patient health conditions [1].Currently, the commercially-available continuous glucose monitors (CGMs) dominate this market due to the rapid, simple and automated electrochemical-based glucose monitoring manner [2].However, drawbacks of CGMs, including the long metallic needles (5 mm to 13 mm) for ISF assessment, and the glucose-detecting enzyme degradation, limit its wide application [2].To address these problems, here we introduce the Wearable Aptalyzer, a novel integrated system fabricated by combining hydrogel microneedle (HMN) arrays for ISF extraction with an electrochemical aptamer-based biosensor for in situ glucose and lactate monitoring.In this design, HMN patches are attached to three-electrode electrochemical chips via a thin layer of low-crosslinked degree methacrylated hyaluronic acid (LC-MeHA) hydrogel (Figure 1a &b).The use of HMNs addresses challenges associated with long needles of CGMs, offering a minimally invasive, biocompatible, yet mechanically robust medium for sensing [1].Aptamers were used as the target recognition element due to their high target binding affinity and selectivity [1,3].Upon target binding, the redox reporter tagged aptamer undergoes a conformational change, which alters the electron transfer efficiency between a redox reporter and the electrode, resulting in a detectable electrochemical signal change (Figure 1a) [3].