Controlled PEGylation of periodic mesoporous organosilica nanospheres for improving their stability in physiological solutions

The stability of periodic mesoporous organosilica (PMO) nanoparticles in physiological solutions greatly affects their potential biomedical applications. Herein, thioether-bridged PMO nanospheres with a diameter of 61 nm are synthesized. Then, the thioether-bridged PMO nanospheres are modified with different molecular weighted polyethylene glycol (PEG) via click reaction for the first time. FI-IR and thermogravimetric analysis confirm the successful modification of PEG on the PMO. The influence of PEG molecular weight on the dispersity and stability of the PMO-PEG in phosphate buffer (PBS) and Dulbecco's modified Eagle's medium (DMEM) is studied. The results show that the PEG coating increases the stability and dispersity of PMO in the biological solutions. The PMO-PEG1K, PMO-PEG2K, and PMO-PEG5K have better stability in PBS solution. The PMO-PEG2K shows best stability and dispersity in DMEM. Over all, this work provides important method and knowledge to guide the modification of PMO for biomedical applications (C) 2019 Chinese Chemical Society and Institute of Materia Medica, Chinese Academy of Medical Sciences. Published by Elsevier B.V. All rights reserved.