Curvature-dependent effects of nanotopography on classical immune complement activation

摘要

The aim of this study was to investigate how the size of nanosized surface features affect classical immune complement activation through adsorption of IgG and the following binding of C1q. By using model surfaces with immobilized SiO2 nanoparticles of different sizes (8, 32 and 68 nm in diameter), three different curvatures with the same chemistry was systematically studied and analyzed using the acoustic sensing technique; Quartz Crystal Microbalance with Dissipation Monitoring (QCM-D). Circular Dichroism (CD) was employed to study any changes in the secondary structure of IgG using a methodology with stacked functionalized substrates. Our results show that the amount of IgG adsorption increased slightly with nanoparticle size, but also showed a strong size/curvature-dependent effect on the following C1q binding, with the highest binding to IgG adsorbed on the largest nanoparticles and a smooth control surface, indicating that classical immune complement activation possibly increase with decreasing curvature. We conclude that the difference in C1q binding was not due to changes in the secondary structure of IgG, suggesting that geometrical arrangement of adsorbed IgG is the determining factor.