Surface features and interfacial behaviour towards proteins of engineered silica nanoparticels

nanobiotechnology. Among the various preparation methods, polymerization in microemulsion of reverse micelles results in spherical NPs highly homogeneous in size, with relevant advantages in behaviour homogeneity in both cell-free and cell tests and applications. Most part of the performances of such NPs in biological media are ruled by their surface/interface features, that have been the subject of this work. The converging use of different methodologies (HR-TEM, Z-potential, DLS, FT-IR, BET, and TGA) made allowance to establish that NPs (50±2 nmin size; monodispersed in water) exhibit a structured, highly hydroxylated surface, where all silanols are engaged in H-bonding with neighbour –OH. Such a rich hydroxyl layer appeared poorly active towards protein (BSA) adsorption (ca. 50% of the theoretical side-on monolayer), producing a thin, incomplete corona around the silica core. Moreover, by in situ FT-IR ATR and UV-CD, it was found that adsorbed BSA underwent severe modifications in terms of both tertiary and secondary structure.