Ocular biocompatibility evaluation of POSS nanomaterials for biomedical material applications

Abstract

The tremendous advancement of polyhedral oligomeric silsesquioxanes (POSSs) has been focused on the field of biomaterial applications including tissue engineering, drug delivery, biomedical devices and biosensors. More recently, POSSs have been used in components of ophthalmic biomedical devices, such as contact lenses and intraocular lenses due to their chemical inertness and transparency. A systematic biocompatibility evaluation of POSS nanomaterials is thus essential. Herein, the ocular biocompatibility and cytotoxicity of POSS nanomaterials were investigated both in vitro and in vivo. Three types of commercial POSS nanomaterials with different functional groups were utilized in this research, including aminoethylaminopropylisobutyl-POSS (NH₂-POSS), mercaptopropylisobutyl-POSS (SH-POSS) and octahydroxypropyldimethylsilyl-POSS (HO-POSS). The cellular metabolic activity, membrane integrality, cell apoptosis and oxidative damage were tested on human lens epithelial cells (HLECs) under different concentrations of POSS nanomaterial exposure. The ocular irritation on rabbit eyes was measured as well. The results show that the studied POSS nanomaterials do not exhibit any significant toxicity to cell growth and proliferation in most cases, except for the NH₂-POSS, which decreases the cellular viability at high concentration. All of the POSS nanomaterials slightly induced oxidative stress as a result of an increase in reactive oxygen species (ROS), however they did not generate cell apoptosis. The animal experiment results also show that no acute ocular irritation can be detected after POSS nanomaterial administration. These results indicate the good ocular biocompatibility of the POSS nanomaterials in most cases, which have great potential in ocular biomedical applications.