Large size dna in vitro and in vivo delivery using chitosan transfection

In modern medicine, many diseases can be treated using gene therapy, which requires a DNA delivery system to prevent DNA from degradation and to transport it to the cells. Liposomal reagents are expensive for such a therapy and new inexpensive biodegradable DNA carriers are required. Chitosan (Ch) is a cationic polymer with promising potency for gene delivery. Some Ch derivatives have been shown to efficiently transfect mammalian cells in vitro. However, there are many inconsistencies in the literature concerning the effectiveness of Ch systems for in vivo gene transfer. The aim of this work was to develop a Ch-based vector for in vivo delivery of a large-size DNA fragment coding for the far-red fluorescent protein (RFP). Among several Ch derivatives, hexanoyl-Ch (HCh) with a molecular weight of 20 kDa effectively transfected cells in vitro. Intratumoural injection of polyplexes in colon and lung tumours resulted in local expression of RFP in tumours.