Probing the biotoxicity of starch nanoparticles in vivo and their mechanism to desensitize β-lactoglobulin

Abstract

Starch nanoparticles (SNPs) were synthesized and characterized in vivo for their subacute biotoxicity. Animal experiments revealed that SNPs would not induce changes in inflammatory cytokines and gut microbiota, avoiding damage to mice's organs. Moreover, SNPs were rapidly excreted from the body after 6 h without any accumulation, demonstrating their biosafety. Based on these findings, SNPs were used for β-lactoglobulin (βLg) desensitization by formation of a protein corona. The thermodynamics and time evolution of βLg's secondary structure were investigated to address the desensitization mechanism. The results showed ∼1600 βLg molecules onto a single SNP coupled with significant changes in secondary structure formed a stable SNPs-βLg corona with binding affinity (Ka) of 8.4 ± 0.5 × 10 5 M −1 . Functionally, the decrease of β-sheet destroyed the conformation of immunoglobulin E (IgE) epitopes and inhibited IgE combining capacity, achieving SNPs' desensitization to βLg. Additionally, it takes ∼2 h to complete changes in βLg's surface hydrophobicity and immunoglobulin E (IgE) combining capacity after incubation with SNPs, consistent with the time evolution of structure changes, indicating protein corona is response for the desensitization. SNPs-βLg corona changed βLg structure, inhibiting the combing with IgE. • Starch nanoparticles (SNPs) were characterized the subacute biotoxicity in vivo and showed biosafety to the mice. • It takes about 2 h to complete secondary structure changes, forming a stable SNPs-βLg corona with about1000 βLg molecules adsorbed. • The time evolution of surface hydrophobicity and IgE combining capacity is corresponding to the changes of secondary structure induce by protein corona.