Preparation and Characterization of Insulin-Loaded Zein/Carboxymethylated Short-Chain Amylose Complex Nanoparticles

In this work, we use antisolvent precipitation to prepare zein/carboxymethylated short-chain amylose (CSA) complex nanoparticles for insulin encapsulation, showing that insulin-loaded zein/CSA complex nanoparticles are homogeneous, generally exhibiting sizes of <200 nm with a narrow distribution (polydispersity index < 0.100), spherical shape, and strong negative charge (-40 mV). Fourier transform infrared spectroscopy analysis reveals that the formation of the above nanoparticles is mainly driven by hydrophobic, hydrogen-bonding, and electrostatic interactions between CSA, insulin, and zein. In comparison to zein nanoparticles, zein/CSA complex nanoparticles feature much higher insulin encapsulation efficiency (45.8 versus 90.5%, respectively) and are essentially nontoxic to Caco-2 cells. Thus, this work provides new insights into the design of drug delivery systems and is expected to inspire their further development.