# Engineering a Glucose‐Responsive Glucagon Prodrug Through Arginine–Phenylboronic Acid Pendant Modification

## TL;DR

A glucose-sensitive glucagon prodrug was developed to automatically release the drug when blood sugar is low, offering protection against hypoglycemia.

## Contribution

A modular, glucose-responsive prodrug design using arginine–phenylboronic acid pendants for self-regulated glucagon delivery.

## Key findings

- The prodrug forms aggregates at high glucose and dissolves when glucose levels drop, triggering glucagon release.
- The lead design with five arginine–PBA repeats showed optimal glucose-responsive behavior and rescued mice from hypoglycemia.
- The system provides prophylactic protection in a diabetic mouse model of insulin overdose without external carrier systems.

## Abstract

Activatable prodrug strategies offer powerful means to control therapeutic presentation in space and time. Here, we report a single‐molecule prodrug design that enables glucose‐responsive activation of a glucagon analog for hypoglycemia protection. The system conjugates dasiglucagon with a synthetic pendant comprised of alternating arginine and phenylboronic acid (PBA) units, designed to couple peptide solubility to glucose concentration. The pendant modulates net charge through glucose‐dependent PBA–diol complexation, driving aggregation under normoglycemia and solubilization under hypoglycemia. The lead pendant contains five arginine–PBA repeats and exhibits optimal glucose‐responsive solubility and charge modulation, forming aggregates at high glucose and dissolving as glucose levels decline. Despite a modest reduction in receptor potency relative to native dasiglucagon, this approach provides significant prophylactic protection in a streptozotocin‐induced diabetic mouse model of insulin overdose, rescuing mice from hypoglycemia and eliminating mortality events. This work demonstrates a proof‐of‐concept for molecularly engineered, metabolite‐responsive glucagon prodrugs that function as on‐demand therapeutic depots. More broadly, it establishes a modular design paradigm for dynamic, self‐regulating peptide therapeutics based on charge modulation rather than external carrier systems.

A single‐molecule glucagon prodrug enables self‐regulated delivery through glucose‐dependent charge modulation. Phenylboronic acid–glucose binding induces aggregation and subcutaneous depot formation at normoglycemia, while glucose depletion restores solubility and triggers glucagon release, providing on‐demand protection against hypoglycemia.© 2026 WILEY‐VCH GmbH