Bio-based starch nanoparticles with controlled size as antimicrobial agents nanocarriers

Starch nanoparticles (SNPs) have been synthesized by nanoprecipitation method using starches from different botanical sources in native form and modified with octenyl succinic anhydride (OSA). SNPs were characterized in terms of size, morphology, charge, XRPD, FTIR and thermal properties. Spherical particles were obtained with sizes ranging from 54 to 108 nm and zeta potential values from −2 to −27 mV. Changes in size and stability related to the % OSA were observed for each starch. Starch granules showed A-type crystalline pattern while a loss of crystallinity was observed for SNPs. FTIR spectra demonstrated that OSA modification was barely affected by the nanoprecipitation and SNPs showed thermal properties similar to those of starch granules. SNPs with specific size can be synthesized by selecting the appropriate starch granules as raw material. This is especially relevant in certain bio-applications, where size must be precisely controlled, e.g., as nanocarriers for drug release or food fortification. To investigate the feasibility of SNPs as nanocarriers, vanillin-loaded SNPs were synthesized, achieving encapsulation efficiencies of 30% and loading capacities of 60%. The antimicrobial activity of vanillin-loaded SNPs was tested against Escherichia Coli (E. coli) with satisfactory results.