Synthesis of poly(ethylene glycol) (PEG) grafted silica nanoparticles with a minimum adhesion of proteins via one-pot one-step method

The main issue associated with silica nanoparticles (NPs) in biological applications is the adhesion of proteins and blood platelets to the NPs surface. In this work, poly(ethylene glycol) (PEG) grafted silica NPs with low protein adsorption characteristics were synthesized using one-pot one-step Stober's method. The particles were synthesized by the hydrolysis of tetraethylorthosilicate (TEOS) in ethanol under controlled reaction conditions and ammonia as the reaction catalyst. The particle synthesis begins with formation of a silica NP and then PEG grafting is carried out in the presence of TEOS resulting in a silica core-PEG shell nanoparticles. The chemical binding of PEG to the silica NPs was confirmed by Fourier transform infrared spectroscopy (FTIR). The obtained results show that by increasing the PEG/TEOS ratio and decreasing the NH4OH concentration, NPs size decreases. The smallest size of PEG grafted NPs (<29 nm) was obtained, when PEG/TEOS ratio and NH4OH concentration were fixed at 9/1 and 0.5 mol L-1, respectively. Remarkable reduction in the affinity between modified silica NPs and protein absorption revealed that our proposed method to fabricate hydrophilized PEG grafted NPs, could be potentially utilized in various bioprocess applications. (C) 2015 Elsevier B.V. All rights reserved.