Combined nanodiamond-mediated drug delivery and upconversion phototherapy for enhanced liver cancer treatment.

To mitigate the significant side effects and limited efficacy of traditional treatment methods, we propose a novel strategy that involves the use of nanodiamond (ND) drug loading combined with up-converted blue light irradiation to achieve highly efficient chemotherapy-photodynamic treatment of liver tumor cells, specifically for the HepG2 cell line. ND-loaded drugs delivered a high concentration of doxorubicin to HepG2 cells, enhancing the chemotherapy effect. Upon exposure to near-infrared irradiation, blue light is excited by up-conversion nanoparticles (UCNPs), thereby activating the production of reactive oxygen demonstrated that the dual-mode therapy of chemotherapy and photodynamic therapy showed significantly improved anticancer effects. The inhibition rates were 77.4 % in vitro and 88.1 % in vivo for HepG2 cells, which are significantly higher than those treated with single photodynamic therapy (18.9 %, 28.6 %) or drug-loaded therapy (62.6 %, 71.4 %). It is noted that under the treatment conditions, no obvious tissue injury or inflammation was observed in the heart, liver, spleen, lung, and kidney samples collected from mice, indicating that the UCNPs and NDs exhibit good biocompatibility and are less toxic to normal cells and tissues, which would be favorable for clinical applications.