title: Chitosan nanogels by template chemical cross-linking in polyion complex micelle nanoreactors.
abstract: Chitosan covalent nanogels cross-linked with genipin were prepared by template chemical cross-linking of chitosan in polyion complex micelle (PIC) nanoreactors. By using this method, we were able to prepare chitosan nanogels using only biocompatible materials without organic solvents. PIC were prepared by interaction between chitosan (X(n) = 23, 44, and 130) and block copolymer poly(ethylene oxide)-block-poly[sodium 2-(acrylamido)-2-methylpropanesulfonate] (PEO-b-PAMPS) synthesized by single-electron transfer-living radical polymerization (SET-LRP). PIC with small size (diameter about 50 nm) and low polydispersity were obtained up to 5 mg/mL. After cross-linking of chitosan with genipin, the nanoreactors were dissociated by adding NaCl. The dissociation of the nanoreactors and the formation of the nanogels were confirmed by (1)H NMR, DLS, and TEM. The size of the smallest nanogels was about 50 nm in the swollen state and 20 nm in the dry state. The amount of genipin used during reticulation was an important parameter to modulate the size of the nanogels in solution.
authors.affiliation: Department of Chemistry, Sapienza University of Rome, P.le A Moro 5, 00185 Rome, Italy.
authors.forename: Flavia
authors.initials: F
authors.lastname: Maggi
authors.forename: Serena
authors.initials: S
authors.lastname: Ciccarelli
authors.forename: Marco
authors.initials: M
authors.lastname: Diociaiuti
authors.forename: Stefano
authors.initials: S
authors.lastname: Casciardi
authors.forename: Giancarlo
authors.initials: G
authors.lastname: Masci
mesh_terms: D000178:Acrylamides / Q000737:chemistry; D001672:Biocompatible Materials / Q000138:chemical synthesis* / Q000378:metabolism; D019149:Bioreactors; D048271:Chitosan / Q000737:chemistry* / Q000378:metabolism; D003432:Cross-Linking Reagents / Q000737:chemistry; D007477:Ions / Q000737:chemistry; D057889:Iridoid Glycosides / Q000737:chemistry* / Q000378:metabolism; D039823:Iridoids; D009682:Magnetic Resonance Spectroscopy; D008823:Micelles; D049329:Nanostructures / Q000737:chemistry; D036103:Nanotechnology / Q000379:methods*; D010316:Particle Size; D011092:Polyethylene Glycols / Q000737:chemistry; D058105:Polymerization; D012965:Sodium Chloride / Q000737:chemistry
chemical_list: D000178:Acrylamides; D001672:Biocompatible Materials; D003432:Cross-Linking Reagents; D007477:Ions; D057889:Iridoid Glycosides; D039823:Iridoids; D008823:Micelles; D011092:Polyethylene Glycols; D012965:Sodium Chloride; D048271:Chitosan; C007834:genipin