Objective To investigate the antitumor efficacy of near-infrared photothermal therapy (NIPT) at different doses of gold nanorods (GNRs) and near-infrared light on gastric cancer SGC-7901 cells in vitro.

Methods GNRs were prepared by seed-mediated growth method, and their morphology, particle size and light absorption were detected. The inhibitory rates of GNRs on the proliferation of SGC-7901 cells were measured by CCK-8. The inhibitory rates of GNRs at different concentrations and NIPT at different powers on the proliferation of SGC-7901 cells were calculated. Meanwhile, the apoptosis of gastric cancer cells was detected by Annexin V-FITC/PI fluorescence method, and the Caspase-3 and Caspase-9 enzyme activities were detected by spectrophotometry.

Results The synthesized GNRs had a longitudinal plasmon resonance absorption peak at around 790nm. The cytotoxicity of pure GNRs was really low. However, NIPT had obvious antitumor effects on gastric cancer cells. With the increase of GNRs dose and near-infrared light power, the cell growth inhibition rate increased significantly. After administration of 40μg/ml GNRs for 1h and 3.0W/cm² near-infrared radiation for 2min, the cell growth inhibition rate reached 93.4%. One hour after treatment, part of the cells were in early apoptotic stage; while three hours after treatment, the cells were in advanced apoptosis or death state, and the Caspase-3, Caspase-9 enzyme activity increased about one fold, compared with those of control group.

Conclusion GNRs-mediated NIPT has obvious antitumor and apoptosis induction effects on gastric cancer cells.