Optically Responsive Gold Nanorod−Polypeptide Assemblies

Abstract

Environmentally responsive nanoassemblies based on polypeptides and nanoparticles can have a number of promising biological / biomedical applications. We report the generation of gold nanorod (GNR)-elastin-like polypeptide (ELP) nanoassemblies whose optical response can be manipulated based on exposure to near infrared (NIR) light. Cysteine-containing ELPs were self-assembled on gold nanorods mediated by gold-thiol bonds, leading to the generation of GNR-ELP nanoassemblies. Exposure of GNR-ELP assemblies to near-infrared (NIR) light resulted in the heating of gold nanorods due to surface plasmon resonance. Heat transfer from the gold nanorods resulted in an increase in temperature of the self-assembled ELP above its transition temperature (T t ), which led to a phase transition and aggregation of the GNR-ELP assemblies. This phase transition was detected using an optical readout (increase in optical density); no change in optical behavior was observed in case of either ELP alone or GNR alone. The optical response was reproducibele and reversible across a number of cycles following exposure to or removal of the laser excitation. Our results indicate that polypeptides may be interfaced with gold nanorods resulting in optically responsive nanoasssemblies for sensing and drug delivery applications.

Self-assembling elastin-like peptides growth factor chimeric nanoparticles for the treatment of chronic wounds

“…Generation of the Fusion Protein Expression Plasmid. The plasmids containing the elastin cassette V40C2 and recombinant KGF have been described previously (32,37). We used PflMI and BglI enzymes for generating of the fusion protein as has been described previously (26).…”

Applications of elastin-like polypeptides in drug delivery

“…This approach has been explored with an ELP containing two cysteine guest residues that allowed coupling to gold nanorods by chemisorption of the thiols onto the gold nanorod surface [111]. The local plasmon resonance of the nanorods resulted in heating of the particles in response to illumination with near-infrared light.…”

Generation of Polypeptide-Templated Gold Nanoparticles using Ionizing Radiation

“…C n ELPs present in the system can act as templating and/or capping agents for gold nanoparticles; gold−thiol interactions allow for the attachment of the C n ELPs to the surface of the gold nanoparticles. 36 Gold ions begin to nucleate to form gold nanospheres upon reduction to zerovalent states, following exposure to ionizing radiation. The C n ELPs present in the system help stabilize the gold nanoparticles and prevent them from aggregating, as seen in Figure 1.…”