Volumetric optoacoustic temperature mapping in photothermal therapy with silica-coated gold nanorods

Owing to their high photothermal conversion efficiency, gold nanoparticles (AuNPs) absorbing light in the near-infrared (NIR) range hold great potential as dual-purpose agents for simultaneous optoacoustic (OA) imaging and photothermal therapy (PTT). As OA signals generated by short-pulsed lasers enable deep-tissue mapping of the nanoparticle biodistribution, they can be further used to enhance localized hyperthermia within these targeted areas. While OA temperature monitoring during AuNPs-assisted PTT has been essential for effective therapy, it has largely been hindered by the OA signal decay caused by photodegradation of the particles. In this work, we demonstrate the feasibility of temperature mapping in PTT in both phantoms and post-mortem mice via silica-coated gold nanorods with enhanced photostability under laser energy densities required for imaging and therapy.