One-pot synthesis of polypeptide-gold nanoconjugates for in vitro gene transfection.

We present a general strategy to create polypeptide-gold nanoconjugates by a one-pot synthesis approach, where polypeptides act not only as capping agents but also as reductants for the formation of gold nanoparticles without the need of an additional reducing agent. The present approach is environmentally benign, facile, and flexible for the design of functional polypeptide-gold nanoconjugates. As a demonstration of as-synthesized nanoconjugates for biomedical applications, the resulting positively charged polypeptide-conjugated gold nanoparticles are applied for gene delivery. A gradual and prolonged intracellular uptake and transfection is achieved, and transfection activity is maintained for almost two weeks with no obvious cytotoxicity. The biologically based method presented in this work will provide a new alternative in creating a variety of multifunctional polypeptide-metallic nanoconjugates in a simple and straightforward manner, which will be more advantageous for their applications in biomedicine.