Gold nanorod-mediated photothermolysis induces apoptosis of macrophages via damage of mitochondria.

AIMS Induction of apoptosis or necrosis in activated macrophages by gold nanorod-mediated photothermolysis is demonstrated and the mechanisms underlying the processes are investigated. MATERIALS & METHODS Gold nanorods were functionalized with cysteine-octaarginine peptides (R8-NRs). Uptake of R8-NRs by activated macrophages was monitored by two-photon luminescence imaging. The laser irradiation conditions were controlled to induce apoptosis or necrosis to R8-NR-internalized macrophages. Mitochondrial damage and reactive oxygen species overproduction during photothermolysis was investigated by confocal fluorescence microscopy and transmission-electron microscopy. RESULTS Activated macrophages efficiently uptake R8-NRs both in vitro and in live animals. Laser irradiation of internalized nanorods with controlled power density induces apoptosis of macrophages via intracellular perturbation and subsequent injury of mitochondria. CONCLUSIONS Gold nanorod-mediated photothermolysis provides one promising way to eliminate activated macrophages in autoimmune and inflammatory diseases.