Using Dextran-encapsulated gold nanoparticles as insulin carriers to prolong insulin activity

Diabetes mellitus is commonly treated with painful insulin injections. We aim to explore drug carriers that can prolong insulin activity. Dextran-encapsulated gold NPs (AuNPs@Dextran) that can bind with insulin are used as insulin carriers. The affinity ( = ∼42 pM) between insulin and insulin receptors on the cells is much higher than that ( = ∼4.02 μM) of insulin and AuNPs@Dextran. Thus, insulin released from the AuNP@Dextran-insulin conjugates to maintain kinetic equilibrium and prefers to bind to the insulin receptor. The slow release of insulin from the AuNP@Dextran-insulin conjugates facilitates the lasting of insulin activity. AuNP@Dextran-insulin conjugates can prolong insulin activity to 12 h, whereas free form insulin loses activity after 4 h in adipocyte cells. AuNPs@Dextran are suitable carriers that can prolong insulin activity.