Golden Buckwheat Extract–Loaded Injectable Hydrogel for Efficient Postsurgical Prevention of Local Tumor Recurrence Caused by Residual Tumor Cells

To prevent local tumor recurrence caused by possible residual cancer cells after surgery, avoid toxicity of systemic chemotherapy and protect the fragile immune system of postsurgical patients, an increasing amount of attention has been paid to local anti–cancer drug delivery systems. In this paper, golden buckwheat was first applied to prevent post–operative tumor recurrence, which is a Chinese herb and possesses anti–tumor activity. Golden buckwheat extract–loaded gellan gum injectable hydrogels were fabricated via Ca(2+) crosslinking for localized chemotherapy. Blank and/or drug–loaded hydrogels were characterized via FT–IR, TG, SEM, density functional theory, drug release and rheology studies to explore the interaction among gellan gum, Ca(2+) and golden buckwheat extract (GBE). Blank hydrogels were non–toxic to NIH3T3 cells. Of significance, GBE and GBE–loaded hydrogel inhibited the proliferation of tumor cells (up to 90% inhibition rate in HepG2 cells). In vitro hemolysis assay showed that blank hydrogel and GBE–loaded hydrogel had good blood compatibility. When GBE–loaded hydrogel was applied to the incompletely resected tumor of mice bearing B16 tumor xenografts, it showed inhibition of tumor growth in vivo and induced the apoptosis of tumor cells. Taken together, gellan gum injectable hydrogel containing GBE is a potential local anticancer drug delivery system for the prevention of postsurgical tumor recurrence.