Preparation of vapreotide-templated silver nanocages and their photothermal therapy efficacy

Vapreotide acetate (Vap) was used as a biotemplate to synthesize silver nanocages through direct co-incubation of a AgNO3 solution, following by reduction using fresh NaBH4. The characterized vapreotide-templated silver nanocages (Vap-AgNCs) presented a wide and red shifted absorption band with a maximum between 480 nm and 800 nm and possessed a uniform structure with a face-centered cubic crystal structure. The biocompatibility of Vap-AgNCs was assessed using the MTT method, indicating Vap-AgNCs had better biocompatibility when its concentration was lower than 2.5 × 10− 4 mmol·L− 1. The photothermal characteristics of Vap-AgNCs were analyzed with laser irradiation (808 nm, 1.5 W·cm− 2) and the results showed that the temperature of the Vap-AgNCs solution reached 45 °C starting from 25 °C within 5 min. Additionally, Vap-AgNCs with a laser led to HeLa cell death. Therefore, the prepared Vap-AgNCs is expected to be an effective photothermal therapy agent.