Multifunctional bismuth oxide (Bi₂O₃) particles: Evidence for selective melanoma therapy

Abstract The current study investigates the therapeutic and optical properties of bismuth oxide (Bi₂O₃) particles for selective melanoma therapy and prevention. The Bi₂O₃ particles were prepared using a standard precipitation method. The Bi₂O₃ particles induced apoptosis in human A375 melanoma cells but not human HaCaT keratinocytes or CCD‐1090Sk fibroblast cells. This selective apoptosis appears to be associated with a combination of factors: increased particle internalization (2.29 ± 0.41, 1.16 ± 0.08 and 1.66 ± 0.22‐fold of control) and enhanced production of reactive oxygen species (ROS) (3.4 ± 0.1, 1.1 ± 0.1 and 2.05 ± 0.17‐fold of control) in A375 cells compared to HaCaT and CCD‐1090SK cells, respectively. As a high‐Z element, bismuth is also an excellent contrast agent for computer tomography, which renders Bi₂O₃ a theranostic material. Moreover, Bi₂O₃ displays high UV absorption and low photocatalytic activity compared to other semiconducting metal oxides, which opens further potential fields of application as a pigment or as an active ingredient in sunscreens. Overall, this study demonstrates the multifunctional properties of Bi₂O₃ particles surrounding the treatment and prevention of melanoma.