BPS2026 – DNA-mediated plasmonic nanoparticle tethering to render macromolecular assemblies photosensitive to pulsed laser irradiation

The ability to control macromolecular assemblies with light would be transformative for a number of applications such as nanocarriers and drug delivery. Light, specifically pulsed laser irradiation, is an ideal stimulus due to its biocompatibility and high spatiotemporal control. Plasmonic nanoparticles (PNPs), such as gold nanoparticles (AuNPs), can act as photosensitizers due to their strong localized surface plasmon resonance. The photomechanical and photothermal effects of PNPs on nearby assemblies depend on a variety of laser parameters (i.e., pulse duration and energy) and nanoparticle characteristics (i.e., size, shape, and location). In this work, AuNPs are incorporated into two different macromolecular assemblies to investigate their behavior upon pulsed laser irradiation. The first such photosensitive macromolecular assembly employs cholesterol membrane anchors and DNA hybridization to tether AuNPs to the exterior of a polymersome, a bilayer vesicle composed of diblock copolymer (PEO 20 - b -PBd 35 ). This novel method expands the range of PNP sizes and shapes that can be introduced into the system without having to alter the vesicle self-assembly or membrane tethering process. The plasmonic polymersome assembly is characterized using cryogenic electron microscopy, dynamic light scattering (DLS), ultraviolet-visible light (UV-Vis) spectroscopy, and fluorescence spectroscopy techniques before and after ultrafast pulsed laser irradiation to investigate the response. The second photosensitive assembly developed in this work is AuNP-decorated DNA origami. DNA hybridization is utilized to conjugate AuNPs to defined origami positions. The resulting nanostructure is characterized both before and after pulsed laser irradiation using atomic force microscopy, DLS, and UV-Vis spectroscopy to examine photoinduced changes such as nanopore formation or structural degradation. Together, these studies establish new strategies for light-responsive nanoscale assemblies and provide insight into the role of AuNP characteristics and irradiation parameters on structural disruption in response to pulsed laser irradiation.