Colloidal crystal microneedle patch for glucose monitoring

Blood glucose monitoring is a daily routine of people with type 1 or advanced type 2 diabetes. Efforts on minimizing invasiveness, improving portability, and enhancing sustainability of the existing glucose monitoring devices are demanding for elevating patient compliance. Here, we describe a minimally invasive colloidal crystal microneedle (MN) patch for naked-eye glucose monitoring. The glucose-responsive colloidal crystal (GCC)-MN is designed with a polymeric core to mechanically support a shell of GCC for glucose sensing and reporting. The GCC-MN patch could translate the glucose concentrations into naked-eye distinguishable color changes within 5 min, and such glucose responsiveness is reversible. Demonstrated in a type 1 diabetic mouse model, the interstitial fluid extraction, glucose sensing, and resulting glucose-relevant color display procedures are simultaneously achieved with this GCC-MN patch.