title: Utilization of micelles formed from poly(ethylene glycol)-block-poly(epsilon-caprolactone) block copolymers as nanocarriers to enable hydrophobic red two-photon absorbing emitters for cells imaging.
abstract: A hydrophobic two-photon absorbing (2PA) red emitter (R) was successfully incorporated into micelles formed from two block copolymers, poly(epsilon-caprolactone)-block-poly(ethylene glycol)s, for imaging and toxicity studies. In micelles, the chromophore R exhibits a 2PA cross-section of 400 GM (1 GM = 1 x 10(-50) cm(4) s photon(-1) molecule(-1)) at 820 nm, which is among the highest values reported for red 2PA emitters. The micelles with a cationic amino moiety-containing poly(ethylene glycol) corona showed an enhancement of cell internalization and delivered the dye into the cytoplasmic regions of the mouse macrophage RAW 264.7 cells. In comparison, the dye in micelles with neutral poly(ethylene glycol) as corona could not be delivered into the cells. Cytotoxicity of the micelle-R constructs was studied using a 3-(4,5-dimethyl thiazol-2-yl)-2,5-diphenyltetrazolium bromide assay. More than 90% of the cells were viable after they were stained with the dye-containing micelles at different concentrations (dye concentrations of 2-6 muM and polymer concentrations of 0.05-0.15 mg/mL) for 16 h. This is the first reported application of a hydrophobic 2,1,3-benzothiadiazole-containing 2PA red emitter delivered into the cytoplasm of cells for bioimaging and toxicity assessment.
authors.affiliation: Department of Materials Science and Engineering, University of Washington, Box 352120, Seattle, Washington 98195-2120, USA.
authors.forename: Yanqing
authors.initials: Y
authors.lastname: Tian
authors.forename: Wen-Chung
authors.initials: WC
authors.lastname: Wu
authors.forename: Ching-Yi
authors.initials: CY
authors.lastname: Chen
authors.forename: Sei-Hum
authors.initials: SH
authors.lastname: Jang
authors.forename: Meng
authors.initials: M
authors.lastname: Zhang
authors.forename: Tim
authors.initials: T
authors.lastname: Strovas
authors.forename: Judy
authors.initials: J
authors.lastname: Anderson
authors.forename: Brad
authors.initials: B
authors.lastname: Cookson
authors.forename: Yongzhong
authors.initials: Y
authors.lastname: Li
authors.forename: Deirdre
authors.initials: D
authors.lastname: Meldrum
authors.forename: Wen-Chang
authors.initials: WC
authors.lastname: Chen
authors.forename: Alex K-Y
authors.initials: AK
authors.lastname: Jen
mesh_terms: D000042:Absorption / Q000187:drug effects; D000818:Animals; D016923:Cell Death / Q000187:drug effects; D002460:Cell Line; D002470:Cell Survival / Q000187:drug effects; D002850:Chromatography, Gel; D004337:Drug Carriers / Q000737:chemistry*; D057927:Hydrophobic and Hydrophilic Interactions; D021621:Imaging, Three-Dimensional / Q000295:instrumentation*; D007783:Lactones / Q000494:pharmacology*; D008264:Macrophages / Q000166:cytology / Q000187:drug effects; D051379:Mice; D008823:Micelles; D018613:Microscopy, Confocal; D049329:Nanostructures / Q000737:chemistry*; D017785:Photons; D011092:Polyethylene Glycols / Q000494:pharmacology*; D012542:Scattering, Radiation; D012997:Solvents; D013050:Spectrometry, Fluorescence; D013056:Spectrophotometry, Ultraviolet
chemical_list: D004337:Drug Carriers; D007783:Lactones; D008823:Micelles; D012997:Solvents; C521904:poly(ethylene glycol)-block-poly(epsilon-caprolactone); D011092:Polyethylene Glycols