In vivo biocompatibility assessment of (PTFE-PVDF-PP) terpolymer-based membrane with potential application for glaucoma treatment

Abstract

The aim of the work was to evaluate the in vivo biological behaviour of polymeric membrane materials for glaucoma implants. The base material was biostable synthetic terpolymer (PTFE-PVDF-PP) with proved biocompability (PN-EN ISO 10993). The samples manufactured in the form a membrane were subjected to chemical and physical treatment to create an open pore system within the polymer matrix. As a porogenic phase biodegradable natrium alginate in a fibrous form was employed. The non-perforating deep sclerectomy technique was performed in a rabbit model. The clinical observations were made after 14 and 30 days. During the study clinical symptoms of a moderate degree were observed, and histopathological changes were typical for foreign body implantation. At the end stage of the study no significant difference in histopathological assessment was found between control and experimental group. Similarities observed in both groups and relatively mild histopathological changes in the tissue surrounding the implant indicate that the observed symptoms come from a deep scleral trauma caused by surgery, and not by the presence of the implant itself.

Fig. 1

Clinical observations: a Duration of clinical symptoms during 30-day observation; group C control group (eyeballs without implant), group I study group (eyeballs with inserted implant); b Maximum of intensity of clinical symptoms and the course of wound healing after 30-day observation; a statistical difference SD between groups P ≤ 0.05, b SD between days 1 and 14 in study group P ≤ 0.05, c SD between days 1 and 14 in control P ≤ 0.05; c Intensity of clinical symptoms and the course of wound healing after 14 days of observation; a SD between groups I/C P ≤ 0.05, b SD between days 1 and 14 in study group P ≤ 0.05, c SD between days 1 and 14 in control group P ≤ 0.05, d SD between days 14 and 30 in study group P ≤ 0.05; d Intensity of clinical symptoms and the course of wound healing after 30 days of observation; a SD between groups P ≤ 0.05, b SD between days 1 and 14 in study group P ≤ 0.05, c SD between days 1 and 14 in control P ≤ 0.05, d SD between days 14 and 30 in study group P ≤ 0.05

Fig. 2

Histopathological evaluation of removed eyeballs: a 14th day without implant—congestion of sclera, with focal areas of resorption granular tissue, formed in nodules, localized around surgical suture; b 14th day with implant: the implant in central part surrounded by an abundant granular tissue; c 1 month without implant—abundant granular tissue; d 1 month with implant—the implant visible in the central part surrounded by unspecific partially resorption granular tissue, resorption granular tissue can be seen also sub conjunctivally, oedema of cillary body