title: Controlled-release system mediated by a retro Diels-Alder reaction induced by the photothermal effect of gold nanorods.
abstract: Controlled-release systems that respond to external stimuli have received great interest for use in medical treatments such as for drug delivery to specific sites. Gold nanorods have an absorption band at the near-infrared region and convert the absorbed light energy into heat, which is known as a "photothermal effect". Therefore, gold nanorods are expected to act not only as an on-demand thermal converter for photothermal therapy but also as a controller of a drug-release system capable of responding to the near-infrared light irradiation. In this study, to construct a controlled-release system that responds to near-infrared light irradiation, we modified gold nanorods with polyethylene glycol (PEG) through Diels-Alder cycloadducts. When the modified gold nanorods were irradiated by near-infrared light, the PEG chains were released from the gold nanorods because of the retro Diels-Alder reaction induced by the photothermal effect. As a result of the PEG release, the gold nanorods formed aggregates. This type of controlled-release system coupled with the aggregate formation of the gold nanorods triggered by near-infrared light could be expanded to applications of gold nanorods in medical fields such as drug and photothermal therapy.
authors: Department of Applied Chemistry, Faculty of Engineering, Kyushu University, 744 Motooka, Fukuoka 819-0395, Japan.
authors: Shuji
authors: S
authors: Yamashita
authors: Hiromitsu
authors: H
authors: Fukushima
authors: Yasuro
authors: Y
authors: Niidome
authors: Takeshi
authors: T
authors: Mori
authors: Yoshiki
authors: Y
authors: Katayama
authors: Takuro
authors: T
authors: Niidome
mesh_terms: D003500:Cyclization; D006046:Gold / Q000737:chemistry*; D043942:Nanotubes / Q000737:chemistry*; D009942:Organometallic Compounds / Q000138:chemical synthesis / Q000737:chemistry; D010316:Particle Size; D011092:Polyethylene Glycols / Q000737:chemistry; D013696:Temperature
chemical_list: D009942:Organometallic Compounds; D011092:Polyethylene Glycols; D006046:Gold