Comparative enhancement of curcumin cytotoxic photodynamic activity by nanoliposomes and gold nanoparticles with pharmacological appraisal in HepG2 cancer cells and Erlich solid tumor model

Curcumin is a natural pigment that generates singlet oxygen upon light excitation, hence it can be used as a photosensitizer in photodynamic therapy. The extremely low water solubility and poor systemic bioavailability make curcumin a challenging molecule to be used clinically. In this study, two nanocarrier systems for curcumin were prepared and characterized; nanoliposomes and polyvinyl pyrrolidone-capped gold nanoparticles. The dark and photocytotoxicity were investigated as a function of light fluence rate (100 and 200?mW/cm²) on HepG2 cancer cells. In vivo Erlich tumor model was developed and comparison of the tumor volume, survival rate, and histopathological alterations was made for the two nanocarriers. Results showed that both curcumin nanocarriers were successfully prepared and characterized. Light irradiation was able to augment the cytotoxicity of both curcumin liposomes and gold nanoparticles, with the former being superior in cytotoxicity compared to the latter. The tumor size was almost diminished 1 month post-photodynamic treatment for both systems with regression in the number of tumor cells upon histopathological evaluation, with curcumin liposomes producing better tumor regression than gold nanoparticles with comparable survival rate. Liposomes were confirmed to be superior to gold nanoparticles as a photodynamic treatment modality for cancer.