title: Preparation and aggregation behavior of mannose-terminated poly(ethylene glycol)-b-poly(L-leucine) in water.
abstract: Amphiphilic diblock copolymers composed of poly(ethylene glycol) (PEG) and poly(l-leucine) (PLeu) with mannose at the chain end of PEG were synthesized by a combination of ring-opening polymerization (ROP) and click chemistry. First, an α-azido, ω-amino PEG (N(3)-PEG-NH(2)) was synthesized and converted to the corresponding amine hydrochloride (N(3)-PEG-NH(2)·HCl), which was used as a macroinitiator to initiate the ROP of L-leucine-N-carboxyanhydride (Leu-NCA), yielding three amphiphilic block copolymers with different chain lengths of PLeu (N(3)-PEG-b-PLeu). Then, click chemistry of the alkynyl mannose with N(3)-PEG-b-PLeu anchored a mannose moiety to the PEG chain end of the copolymer. The self-assembly behavior of these copolymers in water was investigated using transmission electron microscopy (TEM), laser light scattering (LLS) and circular dichroism (CD). Depending on the copolymer composition and the initial concentration of the copolymer in organic solvent, different morphologies (e.g. spherical micelle, wormlike micelle) were observed. The aggregation behavior was demonstrated to be controlled by secondary structure formation and the hydrophobic interactions of the PLeu segments. With mannose moieties on the surface of the aggregates, these aggregates could bind reversibly the lectin Concanavalin A (Con A).
authors.affiliation: Beijing National Laboratory for Molecular Sciences (BNLMS), Key Laboratory of Polymer Chemistry & Physics of Ministry of Education, Department of Polymer Science and Engineering, College of Chemistry and Molecular Engineering, Peking University, Beijing, China.
authors.forename: Rui
authors.initials: R
authors.lastname: Wang
authors.forename: Gunag-Tao
authors.initials: GT
authors.lastname: Chen
authors.forename: Fu-Sheng
authors.initials: FS
authors.lastname: Du
authors.forename: Zi-Chen
authors.initials: ZC
authors.lastname: Li
mesh_terms: D057927:Hydrophobic and Hydrophilic Interactions; D009682:Magnetic Resonance Spectroscopy; D008358:Mannose / Q000737:chemistry*; D046529:Microscopy, Electron, Transmission; D010455:Peptides / Q000737:chemistry*; D011092:Polyethylene Glycols / Q000737:chemistry*; D011108:Polymers / Q000737:chemistry*; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization; D017550:Spectroscopy, Fourier Transform Infrared; D014867:Water / Q000737:chemistry*
chemical_list: D010455:Peptides; D011108:Polymers; D014867:Water; C027819:polyleucine; D011092:Polyethylene Glycols; D008358:Mannose