Biomimetic Polymer Nanoparticles Embedding Quantum Dots
- PDF / 683,838 Bytes
- 6 Pages / 612 x 792 pts (letter) Page_size
- 12 Downloads / 215 Views
Biomimetic Polymer Nanoparticles Embedding Quantum Dots Kazuhiko Ishihara1, 2 , Yusuke Goto1, and Ryosuke Matsuno1 1 Department of Materials Engineering, 2Department of Bioengineering, The University of Tokyo, 7-3-1, Hongo, Bunkyo-ku, Tokyo 113-8656, Japan ABSTRACT To develop new functional fluorescence probe based on semiconductor nanoparticles, such as quantum dots (QD)s, we investigated polymer particle embedding QDs and covered with artificial cell membrane-biointerface. These nanoparticles were prepared by assembling 2methacryloyloxyethyl phosphorylcholine (MPC) polymer as a platform and biomolecules immobilized on the surface of the nanoparticles. The fluorescence property of QDs remained after embedding in the polymer nanoparticles. The MPC polymer surface showed high resistance to non-specific cellular uptake due to the phosphorylcholine groups in the side chain. On the other hand, when cell-penetration oligopeptide, octaarginine was immobilized on the surface, they could permeate the membrane of cells effectively and good fluorescence based on QDs could be observed. Cytotoxicity and inflammation reaction was not produced by these nanoparticles even after immobilization of octapeptide. In conclusion, we could obtain stable fluorescence polymer nanoparticles covered with artificial cell membrane, which are useful as an excellent bioimaging probe and as a novel evaluation tool for biomolecular function in the target cells. INTRODUCTION QDs ranging in size between 2 nm and 6 nm have unique optical properties: material- and size-dependent emission spectra, a wide absorption spectrum, high quantum yields, simultaneous multi color emissions, and especially excellent resistance to photobleaching [1, 2]. This photostability is a critical feature in most fluorescence applications, particularly for long-term monitoring of labeled substances, and is an area in which QDs have a singular advantage over organic dyes. As QDs themselves are hydrophobic, the key to developing QDs as a tool in biological systems is to achieve good dispersion ability in an aqueous medium, and compatibility with biological components including cells [3-5] The 2-methacryloyloxyethyl phosphorylcholine (MPC) polymers have been synthesized by a conventional free radical copolymerization between MPC and other monomers [6, 7]. The MPC polymers have found a number of biomedical applications because they can provide an artificial cell membrane through coating, blending with other polymers, and grafting to the polymer substrates [8-11]. Water-soluble polymers, including poly(MPC-co-n-butyl methacrylate (BMA)-co-ω-methacryloyloxy poly(ethylene oxide)oxycarbonyl 4-nitrophenoyl (MEONP)) (PMBN) were synthesized [12]. The PMBN was used as a coating material on the nanoparticles to construct cytocompatible platform and immobilize specific biomolecules [12 16]. These nanoparticles are easy to produce, and show the bioinert abilities to suppress nonspecific protein adsorption [13, 15, 16], to avoid phagocytosis from macrophage-like cells [9], and to sustain the
Data Loading...
