Thermally responsive nanomaterials are widely used in biomedical research due to their potential applications in photothermal therapy. Among these, elastin-like polypeptide (ELP) functionalized gold nanoparticles (AuNP@ELP) are promising candidates, because ELPs can undergo self-association above a specific transition temperature (Tt). Here, we report an AuNP@ELP system exhibiting (1) reversible, thermally triggered self-association above Tt, (2) tunability in Tt ranging from 32-43 oC, and (3) enhanced photothermal properties at elevated temperatures. AuNP@ELP particles were prepared by introducing a cysteine (Cys) residue into ELP constructs. AuNP@ELP particles with varying AuNP: ELP ratios were created resulting in a tunability in Tt from 32-40 oC. We found that the position of the ELP Cys residue could be used to introduce additional tunability. Specifically, placing the Cys residue in the center of the ELP shifted the Tt up compared to the original variant, where Cys was at the N-terminus. Finally, we diluted the surface density of ELP by adding a small globular protein during AuNP@ELP synthesis. This third approach also shifted the Tt up. Under near-infrared light (NIR) exposure, for one class of AuNP@ELP, we observed a 19.3 ± 1.6 oC increase in temperature after 10 minutes of irradiation with the system initially at 40 oC. This compares favorably to AuNPs without ELP, which show no change in temperature under similar conditions. With further optimization, AuNP@ELPs may prove to be a useful tool for targeted photothermal therapies.

Engineering thermo-responsive gold nanoparticles for photothermal therapy

ACS Fall 2021

The official archive and repository for all ACS Meetings & Expositions abstracts and select posters or presentations.