Amino acid and gold nanoparticles modified mesoporous silica materials synthesis and their applications in DNA transformation

Abstract

Cytotoxicity and immunogenicity of viral DNA delivery vectors in DNA transformation raises the demand of developing non viral DNA delivery systems which can avoid these problems without compromising transformation efficiency. In this context, we have developed mesoporous silica nanoparticles as non-toxic DNA delivery vehicles. Mesoporous silica nanoparticles were synthesized by hydrolysing the tetraethylorthosilicate dissolved in an organic solvent by the amino acid lysine dissolved in aqueous medium and solid material obtained as a result of hydrolysis was calcined. In a similar manner, we have synthesized pure mesoporous silica nanoparticles (MSN) and gold nanoparticles incorporated silica nanomaterials. These materials designed to have very high surface area, tuneable pores and surface functionalisation in such a way to anchor high amount of DNA. Further, we demonstrate their transformation potential using E. coli DH 5α as a model microorganism used for genetic transformation by a bacterial plasmid that contains the gene for green fluorescence protein (GFP) and ampicillin resistance. Physically mixed pDNA and MSNs / functionalized MSNs were incubated for 2 hours at 37°C for complex formation in different ratios to identify the adequate concentration ratio that give high transformation. Gold functionalized MSNs (Au@MSN) were found to be the most efficient transformation vector due to affinity of gold nanoparticles to the DNA and their bigger pore size. By the use of MSNs and functionalized MSNs we have achieved low cytotoxicity and higher DNA transformation