Guidable GNR-Fe3O4-PEM@SiO2 composite particles containing near infrared active nanocalorifiers for laser assisted tissue welding

Abstract Photothermal therapies utilizing gold nanostructures are widely investigated and used within state-of-the-art noninvasive approaches. Single, isolated gold nanoparticles are unable to produce high enough temperatures to perform a sufficient wound closure, requiring therefore large amounts and concentrations to facilitate a therapeutic effect. In this proof of principle study we prepare composite micro-particles which contain near-infrared laser sensitive gold nanorods (GNRs) and Fe 3 O 4 superparamagnetic particles which are agglommerated in a layered polyelectrolyte multilayer (PEM) matrix. The GNRs-Fe 3 O 4 -PEM particles can be enriched in tissue incisions by applying a magnetic field. With this magnetic filed a targeted agglomeration is observed which is beneficial for near-infrared laser based wound sealing. Mechanical tests show that laser treated skin recovered closest to pristine samples and is comparable with nanoparicle gluing. The healing effect of this system is comparable with clinical sutures and nanoparticle gluing in in-vivo experiments. The observation that internal organs like liver can be welded with such composite particles opens new applications for laser tissue welding.