Toxicity of p(g3T2) Polymer on Human Retinal Pigment Epithelium Cells

Abstract

Purpose : To analyze the effects of the conjugated p(g3T2) polymer, a rapidly expanding material that can increase its volume by a factor of 100, on human retinal pigment epithelium cell proliferation in vitro.

Methods : Human retinal pigment epithelium cells (ARPE-19) were plated for 24 hours on p(g3T2)-coated well plates. The polymer has a polythiophene backbone with ethylene glycol side chains. To coat the plates, 20µL per well of a 1mg/mL polymer/DMSO solution was applied. The plates were shaken gently until the solution was dry. Non-polymer-coated plates were plated with ARPE-19 cells in the same culture media; this was used as the control for this study. Using the label-free confluence measurement of Incucyte® system over a 132-hour time period, both plates were analyzed for percent cell confluency by analyzing the occupied area of the wells, and then a two-way repeated-measures (RM) ANOVA was performed.

Results : The p(g3T2)-coated plate showed an increase in overall percent confluency from 35.5% to 79.7% over 132 hours (Figure 1). When compared to the control, the confluency of the p(g3T2)-coated plate became significantly lower after 56 hours and remained lower throughout the rest of the study (p=0.0002). In addition, the overall confluency rate of the p(g3T2)-coated polymer was lower than that of the control visualized in the differing slopes in Figure 1.

Conclusions : The increase in ARPE-19 cell proliferation when plated on the p(g3T2)-coated plate suggests the p(g3T2) polymer did not cause any severe toxic effects. The polymer did produce a lower percentage of confluency when compared to the control. This may be due to the polymer physically hindering the cells from adhering to the surface of the plate. This pilot study suggested that p(g3T2) had a mild effect on ARPE-19 cell proliferation, but no apparent widespread cell death was observed. Further studies using different cell lines and ex vivo tissues treated with p(g3T2) are underway to establish a preclinical safety profile of this polymer with many potential therapeutic applications.

This is a 2021 ARVO Annual Meeting abstract.

 

Figure 1: Percent confluency of treatment groups over time