title: Large payloads of gold nanoparticles into the polyamine network core of stimuli-responsive PEGylated nanogels for selective and noninvasive cancer photothermal therapy.
abstract: A biocompatible photothermal nanomedicine based on a PEGylated nanogel containing gold nanoparticles (GNPs) in a cross-linked network core of stimuli-responsive poly[2-(N,N-diethylamino)ethyl methacrylate] (PEAMA) gel for cancer photothermal therapy (PTT) was prepared through the reduction of Au(iii) ions without any reducing agents. The influence of the reduction conditions, such as pH, temperature, and N/Au ratio (molar ratio of the amino groups in the PEGylated nanogel to the Au(iii) ions), on the formation of the GNPs in the stimuli-responsive PEAMA gel core (reducing environment) was also studied. Note that the PEGylated nanogel containing GNPs prepared at pH 6, 60 degrees C and N/Au = 1 (PEGylated GNG (1)) was found to have the highest GNP-loading capacity with a diameter of about 8 nm, as observed by TEM; viz., about 27 GNPs formed in a single PEAMA gel core. PEGylated GNG (1) showed a remarkable photothermal efficacy (DeltaT = 7.7 degrees C) under irradiation with Ar ion (Ar(+)) laser (514.5 nm) at a fluence of 39 W cm(-2) for 6 min (14 kJ cm(-2)). Note that PEGylated GNG (1) showed non-cytotoxicity in the absence of irradiation with Ar(+) laser (480 microg mL(-1): > 90% cell viability), whereas pronounced cytotoxicity (IC(50) = 110 microg mL(-1)) was observed for PEGylated GNG (1) under irradiation with Ar(+) laser at a fluence of 26 W cm(-2) for 5 min (7.8 kJ cm(-2)), because of the heat-generation from the GNPs in the cells, which resulted in selective and noninvasive cancer PTT. Thus, PEGylated GNG (1), which has a high GNP-loading capacity, would be a promising nanomedicine for cancer PTT.
authors.affiliation: Graduate School of Pure and Applied Sciences, University of Tsukuba, 1-1-1 Tennoudai, Tsukuba, Ibaraki 305-8573, Japan.
authors.forename: Takahito
authors.initials: T
authors.lastname: Nakamura
authors.forename: Atsushi
authors.initials: A
authors.lastname: Tamura
authors.forename: Hiroki
authors.initials: H
authors.lastname: Murotani
authors.forename: Motoi
authors.initials: M
authors.lastname: Oishi
authors.forename: Yuta
authors.initials: Y
authors.lastname: Jinji
authors.forename: Kiyoto
authors.initials: K
authors.lastname: Matsuishi
authors.forename: Yukio
authors.initials: Y
authors.lastname: Nagasaki
mesh_terms: D006046:Gold / Q000737:chemistry*; D006367:HeLa Cells; D006801:Humans; D006863:Hydrogen-Ion Concentration; D053768:Metal Nanoparticles / Q000737:chemistry* / Q000633:toxicity / Q000648:ultrastructure; D008689:Methacrylates / Q000737:chemistry; D000080385:Nanogels; D009369:Neoplasms / Q000628:therapy*; D009757:Nylons / Q000737:chemistry; D010084:Oxidation-Reduction; D011073:Polyamines / Q000737:chemistry*; D011092:Polyethylene Glycols / Q000737:chemistry* / Q000633:toxicity; D011094:Polyethyleneimine / Q000737:chemistry* / Q000633:toxicity; D013056:Spectrophotometry, Ultraviolet; D013696:Temperature
chemical_list: D008689:Methacrylates; D000080385:Nanogels; D009757:Nylons; D011073:Polyamines; C109846:poly(2-(diethylamino)ethyl methacrylate); C413692:polyethylene glycol polyethyleneimine nanogel; D011092:Polyethylene Glycols; D006046:Gold; D011094:Polyethyleneimine