No abstract

Aim Nanoparticles (NPs) have been receiving potential interests in protein delivery and cell therapy. As a matter of fact, NPs may be used as great candidates in promoting cell therapy by catalase (CAT) delivery into high oxidative stress tissues. However, for using NPs like SiO 2 as carriers, the interaction of NPs with proteins and mesenchymal stem cells (MSCs) should be explored in advance. Methods In the present study, the interaction of SiO 2 NPs with CAT and human MSCs (hMSCs) was explored by various spectroscopic methods (fluorescence, circular dichroism (CD), UV-visible), molecular docking and dynamics studies, and cellular (MTT, cellular morphology, cellular uptake, lactate dehydrogenase, ROS, caspase-3, flow cytometry) assays. Results Fluorescence study displayed that both dynamic and static quenching mechanisms and hydrophobic interactions are involved in the spontaneous interaction of SiO 2 NPs with CAT. CD spectra indicated that native structure of CAT remains stable after interaction with SiO 2 NPs. UV-visible study also revealed that the kinetic parameters of CAT such as Km, Vmax, Kcat , and enzyme efficiency were not changed after the addition of SiO 2 NPs. Molecular docking and dynamics studies showed that Si and SiO 2 clusters interact with hydrophobic residues of CAT and SiO 2 cluster causes minor changes in the CAT structure at a total simulation time of 200 ps. Cellular assays depicted that SiO 2 NPs induce significant cell mortality, change in cellular morphology, cellular internalization, ROS elevation, and apoptosis in hMSCs at higher concentration than 100 µg/mL (170 µM). Conclusion The current results suggest that low concentrations of SiO 2 NPs induce no substantial change or mortality against CAT and hMSCs, and potentially useful carriers in CAT delivery to hMSC.