No 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.

The AV1 video compression format is developed by the Alliance for Open Media consortium. It achieves more than a 30% reduction in bit rate compared to its predecessor VP9 for the same decoded video quality. This article provides a technical overview of the AV1 codec design that enables the compression performance gains with considerations for hardware feasibility.