Histidine and arginine conjugated starch-PEI and its corresponding gold nanoparticles for gene delivery.

The high surface energy of gold nanoparticles (GNPs) along with its unique physical and chemical properties delivers it as an effective nonviral gene delivery platform for anticancer treatments. GNPs were synthesized by using starch-PEI in which PEI act as reducing agent and starch as a stabilizer. Cytocompatibility studies carried out in C6 cells revealed that gold modification significantly improved the percentage cell viability even at higher polymer concentration. Irrespective of excellent cellular internalization, the transfection efficiency studied with p53 plasmid was found to be compromised with gold modification. For better transfection efficiency, we further modified starch-PEI with amino acids (l-Arginine, l-Histidine) and synthesized the corresponding GNPs. Though starch-PEI gold nanoparticles exhibited low transfection, its amino acid modified counterparts were found to have good transfection efficiency along with low cytotoxicity. It was found that the GNPs containing l-Arginine showed improved transfection efficiency. Hence, it can be inferred that selective amino acid modification is beneficial for improving the transfection efficiency.