Multifunctional bismuth oxide (Bi₂ O₃ ) particles: Evidence for selective melanoma therapy

The current study investigates the therapeutic and optical properties of bismuth oxide (Bi₂ O₃ ) particles for selective melanoma therapy and prevention. The Bi₂ O₃ particles were prepared using a standard precipitation method. The Bi₂ O₃ 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 Bi₂ O₃ a theranostic material. Moreover, Bi₂ O₃ 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 Bi₂ O₃ particles surrounding the treatment and prevention of melanoma.