Engineering silica-stabilized Pickering emulsions as versatile protein carriers.

Oil-in-water (o/w) Pickering emulsions (PEs), featuring multi-leveled structures and particle-assembled interfaces, have emerged as promising platforms for biomedical applications, due to their superior stability and biocompatibility compared to conventional surfactant-stabilized emulsions. In this study, silica nanoparticles (SNPs) with tunable sizes, surface charges, and morphologies were synthesized and utilized as stabilizers for o/w PEs. Bovine serum albumin and varicella-zoster virus glycoprotein E were selected as model proteins to evaluate the feasibility of SNP-stabilized PEs as protein carriers. Our findings demonstrate that the droplet size, stability, and protein adsorption efficiency of PEs can be precisely tailored by modulating the physicochemical properties of SNPs, particle-protein interactions, interfacial areas, and emulsification strategies. Notably, the co-loading of antigens and immunostimulants into PEs exhibited satisfactory biocompatibility and synergistically enhanced immune responses. This study not only provides a comprehensive understanding about the structure-function relationship between SNP properties, PE stability, and protein adsorption efficiency but also inspires the rational design of SNP-stabilized PEs as versatile protein carriers for applications in drug delivery and novel vaccine adjuvants.