Low-work-function LaB6 for realizing photodynamic-enhanced photothermal therapy

Abstract

There is great potential for photodynamic therapy (PDT)-enhanced photothermal therapy (PTT) to be used for tumor therapy, especially for the single material-mediated process that could greatly simplify the experimental arrangements. This study presents a new cancer phototherapeutic agent consisting of low-work-function lanthanum hexaboride particles, which are excellent light absorbers in the near-infrared (NIR) region. The photothermal effect and reactive oxygen species production were realized by LaB₆ under NIR light irradiation. Theoretical calculations based on density functional theory confirmed that the strong NIR light absorption by LaB₆ was attributed to the local plasmonic resonance effect and the excellent photodynamic effect derived from the low work function. In vivo treatment of HepG2 tumor-bearing mice revealed that LaB₆-mediated phototherapy resulted in excellent tumor inhibitory effects, and no adverse effects on mice were observed. These results indicate that LaB₆ is a promising phototherapeutic agent for cancer synergetic phototherapy.