Porous SERS Microneedles Integrating Sampling and Sensing for Interstitial Glucose Detection

Abstract

Frequent blood glucose monitoring is crucial for diabetes management, but traditional fingerstick tests are invasive and uncomfortable, leading to decreased patient compliance. Interstitial fluid (ISF) offers a minimally invasive alternative for glucose monitoring, as its glucose levels closely correlate with blood levels. This study presents a porous microneedle (MN) integrated with surface-enhanced Raman scattering (SERS) probes, enabling high-sensitivity and wide-range ISF glucose detection. Glucose enters the MNs via capillary action and is oxidized by glucose oxidase (GOx) to produce hydrogen peroxide (H₂O₂). H₂O₂ then reacts with 4-mercaptophenylboronic acid (4-MPBA) on the SERS substrate, generating 4-mercaptophenol (4-MPhOH) and altering the Raman signal. By analyzing the intensity ratio between the resulting 4-MPhOH and initial 4-MPBA peaks, glucose concentration can be quantified. In vitro experiments demonstrated stable and accurate detection within the 0–15 mM glucose range, and animal studies confirmed its feasibility for in vivo use. This SERS-based porous MN technology offers a minimally invasive, highly sensitive, and convenient solution for glucose management and point-of-care diagnosis in diabetes patients.