Keratin-based Nanoparticles for Oral Delivery of Insulin

Abstract

Abstract Successful oral insulin administration can considerably enhance the quality of life (QOL) of diabetes patients who must frequently take insulin injections. Oral insulin administration, on the other hand, is seriously hampered by gastrointestinal enzymes, wide pH range, mucus, and mucosal layers, which limits insulin oral bioavailability to ≤ 2%. Herein, we prepared a simple, inexpensive and safe keratin-based nanoparticles (NPs) to encapsulate sufficient insulin to realize highly efficient oral insulin delivery. The optimized NPs (β-CD-K-IN-DG) achieved high insulin loading (encapsulation efficiency (98.52%) and loading capacity (32.81%)) while protecting insulin from acid and enzymatic degradation. In vivo results confirm that β-CD-K-IN-DG prolonged the residence time of insulin and controlled insulin release under physiological conditions, leading to a notable hypoglycemic effect and a high oral bioavailability of 12.27%. Our work demonstrates that keratin-based NPs can protect insulin from the gastric environment and overcome the intestinal barrier, thus providing the possibility for oral insulin delivery.