Preparation and characterization of zwitterionic functionalized starch nanoparticles

Zwitterionic polymers have attracted great attention due to their unique structure, which can be used for various applications, such as the improvement of nanoparticle stability, ion exchange, sewage treatment, and biomedicine. Here, zwitterionic functionalized starch nanoparticles (SNPs) were successfully prepared in two steps by carboxymethylation and quaternization. The structure of the modified SNPs was confirmed using Fourier transform infrared spectroscopy, nuclear magnetic resonance spectroscopy, and elemental analysis. The zwitterionic SNPs with a size of 30-100 nm were well dispersed without aggregation. The relative crystallinity of zwitterionic SNPs (35.2%) was increased compared to that of SNPs (31.7%). The zwitterionic SNPs could be used effectively to absorb dyes, and its isoelectric point was around pH 9.4. The zwitterionic SNPs may be used as nontoxic adsorption carriers that can be used in health foods or drug delivery applications. (C) 2019 Elsevier B.V. All rights reserved.