Real-time phase-contrast imaging of photothermal treatment of head and neck squamous cell carcinoma: an in vitro study of macrophages as a vector for the delivery of gold nanoshells

Photothermal treatment (PTT) using nanoparticles has gained attention as a promising alternative therapy for malignant tumors. One strategy for increasing the selectivity of PTT is the use of macrophages as a cellular vector for delivering nanoparticles. The aim of the present study is to examine the use of macrophages as a cellular vector for efficient PTT and determine the appropriate irradiation power and time of a near-infrared (NIR) laser using realtime phase-contrast imaging. Thermally induced injury and death of cancer cells were found to begin at 44 degrees C to 45 degrees C, which was achieved using the PTT effect with gold nanoshells (NS) and irradiation with a NIR laser at a power of 2 W for 5 min. The peritoneal macrophage efficiently functioned as a cellular vector for the NS, and the cancer cells surrounding the NS-loaded macrophages selectively lost their cellular viability after being irradiated with the NIR laser. (C) 2012 Society of Photo-Optical Instrumentation Engineers (SPIE). [DOI: 10.1117/1.JBO.17.12.128003]