Controllable synthesis and biomedical applications of bismuth-based nanospheres: enhanced photothermal therapy and CT imaging efficiency.

The advancement and utilization of nano-scale biomaterials in the diagnosis and treatment of tumors have been notable over the last few decades, primarily owing to their appealing characteristics such as small particle size, adjustable properties, and remarkable biocompatibility. The creation of nanomaterials possessing versatility and a customizable nature, consequently, holds great promise for advancing healthcare and improving patient outcomes. Here, we report the controllable synthesis of monodisperse bismuth-based (BiS, Bi, and BiO) nanoparticles with uniform spherical morphology and size distribution, and evaluate their potential for CT imaging and photothermal therapy applications. Monodisperse BiS nanospheres were initially synthesized in aqueous solution using a low-temperature precipitation method. Subsequently, Bi and BiO nanospheres were prepared through the NaBH reduction and the HO oxidation of the as-synthesized BiS templates, respectively. Photothermal conversion and CT imaging characterizations confirm the superiority of Bi nanospheres over BiS and BiO nanospheres in terms of their excellent photothermal conversion efficiency (∼40.10%) and CT contrast efficiency (∼34.32 HU mL mg). Furthermore, it is demonstrated that Bi nanospheres exhibit significant advantages in CT imaging and photothermal effects by using the glioma mouse model, notably achieving a tumor area temperature increase to 53.6 °C after near-infrared laser irradiation. This work furnishes theoretical and experimental evidence for bismuth-based nanomaterials as valuable tools in various biomedical applications.