Vertical graphene-coated core-shell microneedle as miniatured sensor for in vivo glucose monitoring

Microneedle-based continuous glucose monitoring systems have advanced diabetes management in pain less manner, but challenges remain regarding detection sensitivity due to limited sensing area. Vertical graphene (VG) with large surface area offers high conductivity and excellent electrochemical properties for miniaturized, high-performance biomedical sensors. In this study, we developed a vertical graphene-coated core-shell microneedle glucose sensor (VCMGS) for continuous monitoring of glucose fluctuations. The VCMGS featured a hollow microneedle as the outer shell for effective skin penetration, coupled with a vertical graphene-modified sensing electrode core for glucose detection subcutaneously. The core-shell structure provides robust mechanical strength, minimizing damage to the sensing area and improving overall sensor stability. Meanwhile, the electrochemical performance and sensitivity of the microneedle electrode was enhanced by VG, enabling reliable, in situ, and real-time physiological signal acquisition from interstitial fluid. The VCMGS exhibited sensitive response to glucose variations, with a well-defined linear relationship, high selectivity, temporal stability, and dependable signal transmission in both in vitro and in vivo experiments, demonstrating high capability for precise, continuous tracking of glucose fluctuations in real time. This work offered potential applicability and benefits in aiding the diagnosis and treatment of diabetes.