title: Encapsulating live cells with water-soluble chitosan in physiological conditions.
abstract: A new class of microcapsules was prepared under physiological conditions by polyelectrolyte complexation between two oppositely-charged, water-soluble polymers. The microcapsules consisted of an inner core of half N-acetylated chitosan and an outer shell of methacrylic acid (MAA) (20.4%)-hydroxyethyl methacrylate (HEMA) (27.4%)-methyl methacrylate (MMA) (52.2%) (MAA-HEMA-MMA) terpolymer. Both 400 and 150 kDa half N-acetylated chitosans maintained good water solubility and supplied enough protonated amino groups to coacervate with terpolymer at pH 7.0-7.4, in contrast to other chitosan-based microcapsules which must be prepared at pH <6.5. The viscosity of half N-acetylated chitosan solutions between 80 and 3000 cPas allowed the formation of microcapsules with spherical shape. Molar mass, pH and concentration of half N-acetylated chitosan, and reaction time, influenced the morphology, thickness and porosity of the microcapsules. Microcapsules formed with high concentration of half N-acetylated chitosan exhibited improved mechanical stability, whereas microcapsules formed with low concentration of half N-acetylated chitosan exhibited good permeability. This 3D microenvironment has been configured to cultivate sensitive anchorage-dependent cells such as hepatocytes to maintain high level of functions.
authors.affiliation: Department of Physiology, Faculty of Medicine, National University of Singapore, Singapore 117597, Singapore.
authors.forename: Jian-Hang
authors.initials: JH
authors.lastname: Zhu
authors.forename: Xian-Wei
authors.initials: XW
authors.lastname: Wang
authors.forename: Susanne
authors.initials: S
authors.lastname: Ng
authors.forename: Chai-Hoon
authors.initials: CH
authors.lastname: Quek
authors.forename: Hai-Ting
authors.initials: HT
authors.lastname: Ho
authors.forename: Xue-Jun
authors.initials: XJ
authors.lastname: Lao
authors.forename: Hanry
authors.initials: H
authors.lastname: Yu
mesh_terms: D000818:Animals; D001672:Biocompatible Materials / Q000737:chemistry*; D018929:Cell Culture Techniques / Q000379:methods*; D002478:Cells, Cultured; D048271:Chitosan / Q000737:chemistry*; D022781:Hepatocytes / Q000166:cytology* / Q000502:physiology*; D008297:Male; D008422:Materials Testing; D008863:Microspheres; D010316:Particle Size; D010539:Permeability; D011109:Polymethacrylic Acids / Q000737:chemistry*; D051381:Rats; D017208:Rats, Wistar; D012995:Solubility; D013718:Tensile Strength; D023822:Tissue Engineering / Q000379:methods*; D014867:Water / Q000737:chemistry*
chemical_list: D001672:Biocompatible Materials; D011109:Polymethacrylic Acids; D014867:Water; D048271:Chitosan