The Effect of Spermidine and Spermine on Chitosan-Mediated Gene Delivery

Abstract

Chitosan (CS) is a biodegradable and highly positive charged polymer that can be utilized as a non-viral vector for gene delivery. However, its transfection efficiency is low. Spermidine (SPD) and spermine (SPM) are ordinary polyamines found in almost all living organisms. Their structures contain tri- and tetra-amine, respectively. The present study aims to elucidate the effect of SPD or SPM on transfection efficiency and cytotoxicity of CS/DNA complexes in human cervical carcinoma (HeLa) cells. The ternary complexes (CS, DNA and SPD or SPM) at different weight ratios and mixing orders were formulated and tested on transfection efficiency. Their particle sizes and charges were also estimated. CS that has a molecular weight of 45,000 Daltons and degree of deacetylation of 85 was able to form complete complex with plasmid DNA expressing enhanced green fluorescence protein (pEGFP-C2) at weight ratio of 4. The SPM/CS/DNA (1:4:1) and SPD/ CS/DNA (512:4:1) complexes illustrated the greatest transfection efficiency. Moreover, the transfection efficiency was affected by the mixing order between CS, DNA and SPD or SPM. For cell toxicity experiments, more than 85% the average cell survival of the complexes were detected by 3-(4,5-dimethylthiazolyl-2)-2,5-diphenyltetrazolium bromide (MTT) cell growth assay. These findings suggest that addition of either SPD or SPM to CS before forming ternary complexes with DNA may significantly improve gene delivery potential in vitro.

Targeted gene delivery to the brain using CDX-modified chitosan nanoparticles

“…Owing to its cationic nature, CS is commonly used as a promising non-viral vector for gene delivery purposes. 12 , 13 Generally, the formation of highly stable polyplexes between negatively charged genetic materials (e.g., pDNA=plasmid DNA) and cationic structures like CS is electrostatically achievable. 14 Of note, inherent lysosomal escape occurs during BBB transfer of several bioactive molecules.…”