title: Surface property and in vitro biodegradation of microspheres fabricated by poly(epsilon-caprolactone-b-ethylene oxide) diblock copolymers.
abstract: Microspheres fabricated by biodegradable polymers with tunable surface properties show great potentials as microcarriers in in vitro cell cultivation and tissue engineering. Herein we reported a new method to regulate the surface property and morphology of microspheres via the synthesis of biodegradable amphiphilic block copolymers with adjustable compositions. The poly(epsilon-caprolactone-b-ethylene oxide) diblock copolymers with functional amino end groups bonding to the PEO block (PCL-b-PEO-NH(2)) were synthesized by sequential ring-opening polymerization with potassium bis(trimethylsilyl) amide as initiator. The copolymers were characterized by gel permeation chromatography (GPC) and (1)H NMR, and then used to fabricate microspheres by w/o/w double emulsion solvent evaporation technique. The surface properties of microspheres were studied by means of scanning electron microscopy (SEM) and confocal laser scanning microscopy (CLSM). The results indicated that both the fabrication conditions and copolymer composition have great influences on the surface morphology and property of microspheres. The reactive amino functional groups are dominantly located on the surface of microspheres. The in vitro degradation of microspheres was studied by following the morphological changes of microspheres. The influences of hydrophilic PEO out-layers on the enzymatic degradation of microspheres were discussed. These microspheres with controllable surface morphology and amino functional groups are expected to be promising alternatives for the further biomimetic modification to promote cell growth on materials.
authors.affiliation: CAS Key Laboratory of Engineering Plastics, Joint Laboratory of Polymer Sciences and Materials, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100080, China.
authors.forename: Guoqiang
authors.initials: G
authors.lastname: Yu
authors.forename: Yu
authors.initials: Y
authors.lastname: Zhang
authors.forename: Xudong
authors.initials: X
authors.lastname: Shi
authors.forename: Zhanshuang
authors.initials: Z
authors.lastname: Li
authors.forename: Zhihua
authors.initials: Z
authors.lastname: Gan
mesh_terms: D000327:Adsorption; D001672:Biocompatible Materials / Q000737:chemistry; D002478:Cells, Cultured; D002845:Chromatography / Q000379:methods; D004867:Equipment Design; D005027:Ethylene Oxide / Q000737:chemistry; D009682:Magnetic Resonance Spectroscopy; D008855:Microscopy, Electron, Scanning; D008863:Microspheres; D008970:Molecular Weight; D010316:Particle Size; D011091:Polyesters / Q000737:chemistry*; D011092:Polyethylene Glycols / Q000737:chemistry*; D011108:Polymers / Q000737:chemistry; D013499:Surface Properties; D013997:Time Factors
chemical_list: D001672:Biocompatible Materials; D011091:Polyesters; D011108:Polymers; C405621:poly(epsilon-caprolactone-co-ethylene oxide); D011092:Polyethylene Glycols; D005027:Ethylene Oxide