Controllable nanostructured surface modification on quantum dot for biomedical application in aqueous medium.
To develop biocompatible polymer modification method on a quantum dot (QD) surface, we have studied poly(2-methacryloyloxyethyl phosphorylcholine) (poly(MPC)) grafting on trioctylphosphine oxide (TOPO)-coated QD (CdSe/ZnS) surface using new strategy with a double functional reversible addition-fragmentation chain transfer (RAFT) agent. Sodium 2-dodecylsulfanylthiocarbonylsulfanyl-2-methyl propionate (DMP-Na) was focused and prepared as the double functional RAFT agent. As the first function, the DMP-Na possessed surface activity that forms micelle in aqueous solution and solubilize the TOPO-coated QD into the solution. The DMP-Na indicated critical micelle concentration (CMC) from surface tension measurement in an aqueous medium. Over CMC, the QD was able to be solubilized into DMP-Na micelle and showed multicolor fluorescence spectra with narrow full-width at half maximum (FWHM) corresponding to diameter of the QD. Additionally, as the second function, the DMP-Na possessed chain transfer agent ability that synthesizes a poly(MPC)-grafted QD in an aqueous medium. In this strategy, fluorescence properties with narrow FWHM and peak top did not change before and after solubilization into the DMP-Na micelle aqueous solution and even after polymerization of the MPC initiated from the DMP-Na. The poly(MPC)-modified QD showed good biocompatibility based on the poly(MPC) properties, and was able to suppress uptake by HeLa cells despite diameter of the poly(MPC)-modified QD was approximately 12 nm.
Department of Materials Engineering, School of Engineering, The University of Tokyo, Hongo, Bunkyo-ku, Tokyo 113-8586, Japan.
Ryosuke
R
Matsuno
Yusuke
Y
Goto
Tomohiro
T
Konno
Madoka
M
Takai
Kazuhiko
K
Ishihara
D015374:Biosensing Techniques / Q000295:instrumentation* / Q000379:methods; D003460:Crystallization / Q000379:methods*; D004867:Equipment Design; D019544:Equipment Failure Analysis; D046911:Macromolecular Substances / Q000737:chemistry; D008422:Materials Testing; D008968:Molecular Conformation; D049329:Nanostructures / Q000737:chemistry* / Q000648:ultrastructure*; D036103:Nanotechnology / Q000295:instrumentation* / Q000379:methods; D010316:Particle Size; D045663:Quantum Dots; D013050:Spectrometry, Fluorescence / Q000295:instrumentation*; D013499:Surface Properties; D014867:Water / Q000737:chemistry
D046911:Macromolecular Substances; D014867:Water