title: Near-infrared light-triggered "on/off" motion of polymer multilayer rockets.
abstract: We describe an approach to modulating the on-demand motion of catalytic polymer-based microengines via near-infrared (NIR) laser irradiation. The polymer multilayer motor was fabricated by the template-assisted layer-by-layer assembly and subsequently deposition of platinum nanoparticles inside and a thin gold shell outside. Then a mixed monolayer of a tumor-targeted peptide and an antifouling poly(ethylene glycol) was functionalized on the gold shell. The microengines remain motionless at the critical peroxide concentration (0.1%, v/v); however, NIR illumination on the engines leads to a photothermal effect and thus rapidly triggers the motion of the catalytic engines. Computational modeling explains the photothermal effect and gives the temperature profile accordingly. Also, the photothermal effect can alone activate the motion of the engines in the absence of the peroxide fuel, implying that it may eliminate the use of toxic fuel in the future. The targeted recognition ability and subsequently killing of cancer cells by the photothermal effect under the higher power of a NIR laser were illustrated. Our results pave the way to apply self-propelled synthetic engines in biomedical fields.
authors.affiliation: State Key Laboratory of Robotics and System (HIT), Academy of Fundamental and Interdisciplinary Sciences, Harbin Institute of Technology , Harbin 150080, China.
authors.forename: Zhiguang
authors.initials: Z
authors.lastname: Wu
authors.forename: Xiankun
authors.initials: X
authors.lastname: Lin
authors.forename: Yingjie
authors.initials: Y
authors.lastname: Wu
authors.forename: Tieyan
authors.initials: T
authors.lastname: Si
authors.forename: Jianmin
authors.initials: J
authors.lastname: Sun
authors.forename: Qiang
authors.initials: Q
authors.lastname: He
mesh_terms: D002384:Catalysis; D003198:Computer Simulation; D004912:Erythrocytes / Q000166:cytology; D006046:Gold / Q000737:chemistry; D006801:Humans; D007259:Infrared Rays; D007834:Lasers; D053768:Metal Nanoparticles / Q000737:chemistry; D046529:Microscopy, Electron, Transmission; D009038:Motion; D009369:Neoplasms / Q000628:therapy*; D010100:Oxygen / Q000737:chemistry; D010455:Peptides / Q000737:chemistry; D010545:Peroxides / Q000737:chemistry; D010777:Photochemistry; D011092:Polyethylene Glycols / Q000737:chemistry; D011108:Polymers / Q000737:chemistry*; D019265:Spectroscopy, Near-Infrared / Q000379:methods*; D013696:Temperature
chemical_list: D010455:Peptides; D010545:Peroxides; D011108:Polymers; D011092:Polyethylene Glycols; D006046:Gold; D010100:Oxygen