title: Plasmon-mediated generation of reactive oxygen species from near-infrared light excited gold nanocages for photodynamic therapy in vitro.
abstract: We have performed fundamental assays of gold nanocages (AuNCs) as intrinsic inorganic photosensitizers mediating generation of reactive oxygen species (ROS) by plasmon-enabled photochemistry under near-infrared (NIR) one/two-photon irradiation. We disclosed that NIR light excited hot electrons transform into either ROS or hyperthermia. Electron spin resonance spectroscopy was applied to demonstrate the production of three main radical species, namely, singlet oxygen ((1)O2), superoxide radical anion (O2(-•)), and hydroxyl radical ((•)OH). The existence of hot electrons from irradiated AuNCs was confirmed by a well-designed photoelectrochemical experiment based on a three-electrode system. It could be speculated that surface plasmons excited in AuNCs first decay into hot electrons, and then the generated hot electrons sensitize oxygen to form ROS through energy and electron transfer modes. We also compared AuNCs' ROS generation efficiency in different surface chemical environments under one/two-photon irradiation and verified that, compared with one-photon irradiation, two-photon irradiation could bring about much more ROS. Furthermore, in vitro, under two-photon irradiation, ROS can trigger mitochondrial depolarization and caspase protein up-regulation to initiate tumor cell apoptosis. Meanwhile, hyperthermia mainly induces tumor cell necrosis. Our findings suggest that plasmon-mediated ROS and hyperthermia can be facilely regulated for optimized anticancer phototherapy.
authors.affiliation: CAS Key Laboratory for Biomedical Effects of Nanomaterials and Nanosafety, Institute of High Energy Physics, Chinese Academy of Sciences , Beijing 100049, China.
authors.forename: Liang
authors.initials: L
authors.lastname: Gao
authors.forename: Ru
authors.initials: R
authors.lastname: Liu
authors.forename: Fuping
authors.initials: F
authors.lastname: Gao
authors.forename: Yaling
authors.initials: Y
authors.lastname: Wang
authors.forename: Xinglu
authors.initials: X
authors.lastname: Jiang
authors.forename: Xueyun
authors.initials: X
authors.lastname: Gao
mesh_terms: D001692:Biological Transport; D006046:Gold / Q000737:chemistry* / Q000378:metabolism / Q000494:pharmacology*; D006367:HeLa Cells; D006801:Humans; D006979:Hyperthermia, Induced; D007259:Infrared Rays; D053078:Membrane Potential, Mitochondrial / Q000187:drug effects / Q000528:radiation effects; D049329:Nanostructures; D010778:Photochemotherapy; D017319:Photosensitizing Agents / Q000737:chemistry / Q000378:metabolism / Q000494:pharmacology; D011092:Polyethylene Glycols / Q000737:chemistry; D017382:Reactive Oxygen Species / Q000378:metabolism*
chemical_list: D017319:Photosensitizing Agents; D017382:Reactive Oxygen Species; D011092:Polyethylene Glycols; D006046:Gold