Biopolymeric Vectors for Enhancing Gene Delivery - A Comparative Evaluation

Gene delivery using nonviral approaches has been extensively studied as a basic tool for intracellular gene transfer and gene therapy. The objective of this work is to comparatively evaluate the expression of reporter transgene using plasmid DNA encoding the green fluorescent protein gene (EGFP-N1) and a standard cationic lipid based transfection reagent Lipofectamine. Gelatin, a biocompatible and biodegradable material, can act as a non-viral delivery vehicle with low toxicity. Positively charged gelatin microparticles (type B, 75 Bloom) were prepared by binary organic solvent (ethanol /acetone) water displacement method. The pEGFP-N1 vector was used as a green fluorescent protein gene and transformed in E. coli DH5α. The quality and quantity of plasmid DNA were observed by spectrophotometric analysis at 260 & 280nm. In this study, plasmid EGFP-N1 was encapsulated in positively charged gelatin microparticles. The GM-DNA particle size was within the range of 670.5 nm with a surface charge of 9.10 mV. The EGFP-N1 Plasmid and polymer complex stability was determined by agarose gel retardation assay. The gel retardation assay of polymer DNA Complex were performed at different N/P ratios of 1:1 ,2:1,4:1,6:1 and 10:1. The transfection efficiency in vitro depends on the molecular weight, charge ratio, and DNA concentration of the GM- DNA as well as the type of cell transfected. The results indicate higher transfection efficiency ~80% of positively charged gelatin microparticles in 24hrs, while lipofectamine gives approximately 65% transfection efficiency after 72hrs. This simple, noninvasive technique of using cationic gelatin to deliver biomolecules provides an efficient delivery strategy for gene therapy and drug delivery.