Abstract: Silica nanoparticles(SiNP), amino-terminated silica nanoparticles(NSiNP), carboxyl-terminated silica nanoparticles(CSiNP) and PEG-terminated nanoparticles(PSiNP) were prepared via the synchronous modification of functional group in water-in-oil microemulsion(hereinafter referred to being modified in oil) and the modification of functional group on the well-prepared SiNP(hereinafter referred to being modified in water) respectively. The dispersibility of different functionalized silica nanoparticles in water suspension was evaluated with sediment velocity and centrifugation velocity. And further analysis of the dispersion behavior was demonstrated through the TEM imaging and hydrodynamic size analyses. The results indicat that the following order of dispersion was observed: CSiNP≥PSiNP>SiNP>NSiNP, when the silica nanoparticles were modified with the same method. In addition, for CSiNP and PSiNP, the dispersibility of the two nanoparticles modified in oil was superior to that of modified in water. At the same time, the nonspecific adsorption of the different functionalized silica nanoparticles modified in oil with the Hela cells was also investigated. There was almost no nonspecification with Hela cells to CSiNP and PSiNP. However, the NSiNP were adsorbed to the Hela cells extensively. These results played important roles in the preparation and further modification of silica nanoparticles that would be well suited in biomedicine.

Key words: Water-in-oil microemulsion, Silica nanoparticles(SiNP), Dispersibility, Nonspecific adsorption