Extracellular biosynthesis of copper sulfide nanoparticles by Shewanella oneidensis MR-1 as a photothermal agent

Photothermal therapy (PTT) is a minimally invasive and effective cancer treatment method and has a great potential for innovating the conventional chemotherapy approaches. Copper sulfide (CuS) exhibits photostability, low cost, and high absorption in near infrared region, and is recognized as an ideal candidate for PTT. However, CuS, as a photothermal agent, is usually synthesized with traditional chemical approaches, which require high temperature, additional stabilization and hydrophilic modification. Herein, we report, for the first time, the preparation of CuS nanoparticles as a photothermal agent by a dissimilatory metal reducing bacterium Shewanella. oneidensis MR-1. The prepared nanoparticles are homogenously shaped, hydrophilic, small-sized (∼5 nm) and highly stable. Furthermore, the biosynthesized CuS nanoparticles display a high photothermal conversion efficiency of 27.2% because of their strong absorption at 1100 nm. The CuS nanoparticles could be effectively used as a PTT agent under the irradiation of 1064 nm. This work provides a simple, eco-friendly and cost-effective approach for fabricating PTT agents.