Antitumor activity of PEG-HAuNS against Hey tumors in nude mice. A: Hey tumor growth curves in mice treated with saline (n = 7), and PEG-HAuNS at doses ranging from 5 mL/kg of 25 OD (n = 7, 3.125 mg/kg), 50 OD (n = 8, 6.25 mg/kg), and 100 OD (n = 8, 12.5 mg/kg). All tumors received NIR laser illumination from the tumor’s surface (2.5 W/cm2, for 3 min) at 24 h after a single dose nanoparticle injection. B: Average weight of tumors in saline- and PEG-HAuNS-treated groups on day 10 after NIR laser illumination. C: Photographs of excised tumors on day 10 after NIR laser illumination. D: Percentage change in mean body weight.