Understanding the curvature effect of silica nanoparticles on lysozyme adsorption orientation and conformation: a mesoscopic coarse-grained simulation study.

In nanobiotechnology applications, curvature of nanoparticles has a significant effect on protein activities. In this work, lysozyme adsorption on different-sized silica nanoparticles (SNPs) was simulated at the microsecond timescale by using mesoscopic coarse-grained molecular dynamics simulations. It is found that, with the increase of nanoparticle size, which indicates a decrease of surface curvature, adsorbed lysozyme shows a narrower orientation distribution and a greater conformation change, as the electrostatic attraction dominates lysozyme adsorption, and this trend is more pronounced on larger SNPs. Interestingly, the effect induced by different SNP surface curvatures is not related to the direct contact area between lysozyme and SNPs, but to the interfacial hydration layer above the silica surface, since a smaller curvature can lead to a stronger interfacial hydration and make the distribution of interfacial water molecules more ordered. Besides, at higher ionic strength, lysozyme conformation is less affected by strongly negatively charged SNPs, especially for larger nanoparticles. This work might shed some light on how to prepare protein coronas with higher bioactivities in nanobiotechnology.