Ex vivo-in vitro protein adsorption and in vivo anti-inflammatory effects of zwitterionized PVA hydrogel implants in the New Zealand albino rabbit eye.

Implantable ocular devices are increasingly used to overcome the drug delivery challenges presented by the physio-anatomical barriers of the eye. Protein adsorption onto the biomaterial occurs within minutes of implantation and is usually the first step in the fouling process that could culminate in implant/device failure, infection, or even death if the infection is not properly managed. The eye can easily be damaged by any inflammatory process due to its immune privilege status, hence, the need for biomaterials that would inherently limit protein adsorption and reduce inflammation. Herein, a super hydrophilic hydrogel ocular device was formulated via facile photo-initiated crosslinking polymerization between polyvinyl alcohol and sulfobetaine methacrylate, 2 polymers that have previously been employed individually, for surface modification of biomaterials towards protein resistance. Protein adsorption onto the hydrogel was studied in vitro and ex vivo using a complex protein solution, and rabbit aqueous and vitreous humour, respectively. In vivo ocular cytocompatibility was studied in New Zealand albino rabbits by subconjunctival implantation over a period of 8 weeks. The concentration of the zwitterionic monomer significantly affected protein adsorption in vitro, and impacted the foreign body response in vivo. In vivo results after 1 week showed a graded acute inflammatory response indicative of tissue repair that resulted in full integration by the 8th week.