Supramolecular Peptide Depots for Glucose-Responsive Glucagon Delivery

Precise blood glucose control continues to be a critical challenge in the treatment and management of type 1 diabetes in order to mitigate both acute and chronic complications. This study investigates the development of a supramolecular peptide amphiphile (PA) material functionalized with phenylboronic acid (PBA) for glucose-responsive glucagon delivery. The PA-PBA system self-assembles into nanofibrillar hydrogels in the presence of physiological glucose levels, resulting in stable hydrogels capable of releasing glucagon under hypoglycemic conditions. Glucose responsiveness is driven by reversible binding between PBA and glucose, which modulates the electrostatic interactions necessary for hydrogel formation and dissolution. Through comprehensive in vitro characterization, including circular dichroism, zeta potential measurements, and rheological assessments, the PA-PBA system is found to exhibit glucose-dependent assembly, enabling controlled glucagon release that is inversely related to glucose concentration. Glucagon release is accelerated under low glucose conditions, simulating a hypoglycemic state, with a reduced rate seen at higher glucose levels. Evaluation of the platform in vivo using a type 1 diabetic mouse model demonstrates the efficacy in protecting against insulin-induced hypoglycemia by restoring blood glucose levels following an insulin overdose. The ability to tailor glucagon release in response to fluctuating glucose concentrations underscores the potential of this platform for improving glycemic control. These findings suggest that glucose-stabilized supramolecular peptide hydrogels hold significant promise for responsive drug delivery applications, offering an approach to manage glucose levels in diabetes and other metabolic disorders.