High-efficiency and safe sulfur-doped iron oxides for magnetic resonance imaging-guided photothermal/magnetic hyperthermia therapy.

Heat therapy is a promising therapeutic modality for cancer treatment due to the minimum adverse effects of selective local hyperthermia; however, the low heating efficiency of heat therapy under safe conditions is an issue for its bioapplication. Here, we report the synthesis of water-dispersible sulfur doped iron oxides (SDIOs) with different phase structures and the exploration of the relationships between the different SDIOs and their induction heating capacities as a guideline to obtain a photo-magnetic hyperthermia agent. The agent exhibits good biocompatibility, excellent photothermal conversion efficiency (55.8%) and great T2 weighted magnetic resonance imaging (63.7 mM-1 s-1). Significantly, the SDIOs effectively eliminate tumours in a biologically safe AC magnetic field range (H·f = 4.3 < 5.0 × 106 kA m-1 s-1) and with 808 nm laser irradiation at a safe density of 0.33 W cm-2; also, they can be mostly metabolized from the body after one month. The work presented here adopts anion-doped iron oxides to dramatically improve photo-magnetic hyperthermia effects and may enable further exploration in thermotherapeutic research.

New Strategy for Specific Eradication of Implant-Related Infections Based on Special and Selective Degradability of Rhenium Trioxide Nanocubes.

The greatest bottleneck for photothermal antibacterial therapy could be the difficulty in heating the infection site directly and specifically to evade the unwanted damage for surrounding healthy tissues. In recent years, infectious microenvironments (IMEs) have been increasingly recognized as a crucial contributor to bacterial infections. Here, based on the unique IMEs and rhenium trioxide (ReO3) nanocubes (NCs), a new specific photothermal antibacterial strategy is reported. These NCs synthesized by a rapid and straightforward space-confined on-substrate approach have good biocompatibility and exhibit efficient photothermal antibacterial ability. Especially when they are utilized in antibiofilm, the expression levels of biofilm-related genes (icaA, fnbA, atlE, and sarA for Staphylococcus aureus) can be effectively inhibited to block bacterial adhesion and formation of biofilm. Importantly, the ReO3 NCs can transform into hydrogen rhenium bronze (HxReO3) in an aqueous environment, making them relatively stable within the low pH of IMEs for photothermal therapy, while rapidly degradable within the surrounding healthy tissues to decrease photothermal damage. Note that under phosphate-buffered saline (PBS) at pH 7.4 without assistant conditions, these ReO3 NCs have the highest degradation rate among all known degradable inorganic photothermal nanoagents. This special and IME-sensitive selective degradability of the ReO3 NCs not only facilitates safe, efficient, and specific elimination of implant-related infections, but also enables effective body clearance after therapy. Solely containing the element (Re) whose atomic number is higher than clinic-applied iodine in all reported degradable inorganic photothermal nanoagents under the PBS (pH 7.4) without any assistant condition, the ReO3 NCs with high X-ray attenuation ability could be further applied to X-ray computed tomography imaging-guided therapy against implant-related infections. The present work described here is the first to adopt degradable inorganic photothermal nanoagents to achieve specific antibacterial therapy and inspires other therapies on this concept.