In-vitro cytotoxicity of Polyethyleneimine on HeLa and Vero Cells

Abstract

The success of gene therapy depends on the choice of a suitable vector that is biocompatible and efficient in delivering therapeutic DNA into disease cells. After more than two decades, such an ideal vector is still a wish. Viral vectors though naturally evolved to transfect cells are immunogenic. As alternatives, non-viral vectors such as polyethyleneimine have been exploited. We decided to investigate the in-vitro cytotoxicity of branched polyethyleneimine 800D, 25kD and linear 20kD on HeLa and Vero cells. At exponential phase, cells were exposed to polymers at concentration range of 0.5 to 1000mg/ml. Cells were MTT assayed after 24, 48 and 72hours for viability (IC50). Linear PEI was less toxic than the branched PEI in both cells. The IC50 (mg/ml) values (Mean±SEM, n=6) post 72hours of PEI800D, 25kD and PEI20kD on HeLa cells were 2.42±0.22, 2.92±0.59, and 3.03±0.11 and for Vero cells, 7.42±0.29, 7.26±0.12, and 6.89±0.53 respectively. Two tailed t-test (P<0.05) of each polymer on both cells 72hours post dosing gave a significant P value of <0.0001. The results indicate that branched PEI800D, PEI25kD and linear PEI20kD are differently apoptotic to HeLa and Vero cells. The toxicity also time, cell line and concentration dependent. More research aimed at improving biocompatibility and transfection efficiency is needed.