1. ¹Department of Chemical and Biomolecular Engineering, University of California at Los Angeles, Los Angeles, California, USA
2. ²Deparment of Molecular and Cell Biology, University of California at Davis, Davis, California, USA

Correspondence: Tatiana Segura, 420 Westwood Plaza, 5531 Boelter Hall, Los Angeles, California 90024, USA. E-mail: tsegura@ucla.edu

Received 16 September 2008; Accepted 9 January 2009; Published online 24 February 2009.

Abstract

The development of techniques to efficiently deliver genes using nonviral approaches can broaden the application of gene delivery in medical applications without the safety concerns associated with viral vectors. Here, we designed a clustered integrin-binding platform to enhance the efficiency and targetability of nonviral gene transfer to HeLa cells with low and high densities of _v3 integrin receptors. Arg-Gly-Asp (RGD) nanoclusters were formed using gold nanoparticles functionalized with RGD peptides and used to modify the surface of DNA/poly(ethylene imine) (PEI) polyplexes. DNA/PEI polyplexes with attached RGD nanoclusters resulted in either 5.4- or 35-fold increase in gene transfer efficiency over unmodified polyplexes for HeLa cells with low- or high-integrin surface density, respectively. The transfection efficiency obtained with the commercially available vector jetPEI-RGD was used for comparison as a vector without clustered binding. JetPEI-RGD exhibited a 1.2-fold enhancement compared to unmodified jetPEI in cells with high densities of _v3 integrin receptors. The data presented here emphasize the importance of the RGD conformational arrangement on the surface of the polyplex to achieve efficient targeting and gene transfer, and provide an approach to introduce clustering to a wide variety of nanoparticles for gene delivery.