Using Dextran-encapsulated Gold Nanoparticles As Insulin Carriers to Prolong Insulin Activity

Aim: Diabetes mellitus is commonly treated with painful insulin injections. We aim to explore drug carriers that can prolong insulin activity. Materials & methods: Dextran-encapsulated gold NPs (AuNPs@Dextran) that can bind with insulin are used as insulin carriers. The affinity (K d = ∼42 pM) between insulin and insulin receptors on the cells is much higher than that (K d = ∼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. Results & discussion: AuNP@Dextran–insulin conjugates can prolong insulin activity to 12 h, whereas free form insulin loses activity after 4 h in adipocyte cells. Conclusion: AuNPs@Dextran are suitable carriers that can prolong insulin activity.