Chitosan-coated triangular silver nanoparticles as a novel class of biocompatible, highly effective photothermal transducers for in vitro cancer cell therapy

One of the relevant directions that nanotechnology is taking nowadays is connected with nanomedicine and specifically related to the use of light and nanoparticles in early diagnosis and effective therapeutics of cancer. Noble-metal nanoparticles can act under laser irradiation as effective photothermal transducers for triggering localized hyperthermia of tumors. In this work we report the performance of newly synthesized chitosan-coated silver nanotriangles (Chit-AgNTs) with strong resonances in near-infrared (NIR) to operate as photothermal agents against a line of human non-small lung cancer cells (NCI-H460). The hyperthermia experiments were conducted by excitation of nanoparticles-loaded cells at 800 nm wavelength from a Ti:Sapphire laser. We found that the rate of cell mortality in the presence of Chit-AgNTs is higher than in the presence of thiolated poly(ethylene) glycol capped gold nanorods (PEG-AuNRs) - a common hyperthermia agent used as reference-, while no destructive effects were noticed on the control sample (cells without nanopartides) under identical irradiation conditions. Additionally, we conducted cytotoxicity assays and found Chit-AgNTs to be efficiently uptaken by the cells while exhibiting good biocompatibility for healthy human embryonic cells (HEK), which is essential for any in vivo applications. Our results reveal a novel class of biocompatible plasmonic nanoparticles with high potential to be implemented as effective phototherapeutic agents in the battle against cancer. (C) 2011 Elsevier Ireland Ltd. All rights reserved.