Development of lyophilized spherical particles of poly(epsilon-caprolactone) and examination of their morphology, cytocompatibility and influence on the formation of reactive oxygen species

Abstract

A common limitation of using polymeric micro- and nanoparticles in long-term conservation is due to their poor physical and chemical stability. Freeze-drying is one of the most convenient methods that enable further reconstitution of micro- and nanoparticles for therapeutical use. Nevertheless, this process generates various stresses during freezing and desiccation steps. This paper underlines the combined outcomes of freeze drying method and physicochemical solvent/non-solvent approach to design biocompatible poly(epsilon-caprolactone) (PCL) nanospheres and evaluate influence of different cryoprotectants (glucose, saccharose, polyvinyl alcohol or polyglutamic acid) on the outcome of freeze-dried PCL particles. Samples were characterized using Fourier transform infrared spectroscopy (FT-IR), scanning electron microscopy (SEM) and dynamic light scattering method (DLS). In vitro studies used, include MTT assay (3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide), testing cytotoxicity as the quality of being toxic to cells, and DCFHDA assay (2’,7’-dichlordihydrofluorescein-diacetate), testing the possible increase in ROS levels. It was found that cryoprotection with 1% glucose solution is an optimal for obtaining uniform, spherical but also biocompatible PCL nanoparticles for biomedical purposes.