title: Gold nanorods as dual photo-sensitizing and imaging agents for two-photon photodynamic therapy.
abstract: Gold nanorods with three different aspect ratios were prepared and their dual capabilities for two-photon imaging and two-photon photodynamic therapy have been demonstrated. These gold nanorods exhibit large two-photon absorption action cross-sections, about two orders of magnitude larger than small organic molecules, which makes them suitable for two-photon imaging. They can also effectively generate singlet oxygen under two-photon excitation, significantly higher than traditional photosensitizers such as Rose Bengal and Indocyanine Green. Such high singlet oxygen generation capability under two-photon excitation was ascribed to their large two-photon absorption cross-sections. Polyvinylpyrrolidone (PVP) coated gold nanorods displayed excellent biocompatibility and high cellular uptake efficiency. The two-photon photodynamic therapy effect and two-photon fluorescence imaging properties of PVP coated gold nanorods have been successfully demonstrated on HeLa cells in vitro using fluorescence microscopy and indirect XTT assay method. These gold nanorods thus hold great promise for imaging guided two-photon photodynamic therapy for the treatment of various malignant tumors.
authors.affiliation: Department of Chemistry, National University of Singapore, 3 Science Drive 3, Singapore 117543.
authors.forename: Tingting
authors.initials: T
authors.lastname: Zhao
authors.forename: Xiaoqin
authors.initials: X
authors.lastname: Shen
authors.forename: Lin
authors.initials: L
authors.lastname: Li
authors.forename: Zhenping
authors.initials: Z
authors.lastname: Guan
authors.forename: Nengyue
authors.initials: N
authors.lastname: Gao
authors.forename: Peiyan
authors.initials: P
authors.lastname: Yuan
authors.forename: Shao Q
authors.initials: SQ
authors.lastname: Yao
authors.forename: Qing-Hua
authors.initials: QH
authors.lastname: Xu
authors.forename: Guo Qin
authors.initials: GQ
authors.lastname: Xu
mesh_terms: D002470:Cell Survival / Q000187:drug effects; D006046:Gold / Q000737:chemistry*; D006367:HeLa Cells; D006801:Humans; D008856:Microscopy, Fluorescence; D043942:Nanotubes / Q000737:chemistry* / Q000633:toxicity; D010778:Photochemotherapy; D017785:Photons; D017319:Photosensitizing Agents / Q000737:chemistry* / Q000633:toxicity; D011205:Povidone / Q000737:chemistry; D026082:Singlet Oxygen / Q000378:metabolism
chemical_list: D017319:Photosensitizing Agents; D026082:Singlet Oxygen; D006046:Gold; D011205:Povidone