title: Preparation and characterization of oxidized starch polymer microgels for encapsulation and controlled release of functional ingredients.
abstract: A novel biocompatible and biodegradable microgel system has been developed for controlled uptake and release of especially proteins. It contains TEMPO-oxidized potato starch polymers, which are chemically cross-linked by sodium trimetaphosphate (STMP). Physical chemical properties have been determined for microgels of different weight ratios of cross-linker to polymer (0.10, 0.15, 0.20, 0.30, and 0.40) and degrees of oxidation (30, 50, 70, and 100%). The charge density of the microgels as determined by proton titration is found to be in good agreement with the expected degree of oxidation (DO). The electrophoretic mobility of the microgel particles is used as a qualitative indicator of the pore size and scales with microgel swelling capacity as expected. The swelling capacity increases with increasing pH and decreasing salt concentration. Preliminary data for the uptake of the globular protein lysozyme by the microgels show it increases with increasing DO and decreasing cross-linker to polymer ratio. Highly charged microgels with intermediate cross-linker to polymer ratios (0.15 and 0.2) are found to be optimal for encapsulating lysozyme.
authors.affiliation: Laboratory of Physical Chemistry and Colloid Science, Dreijenplein 6, 6703 HB Wageningen,The Netherlands. yuan3.li@wur.nl
authors.forename: Yuan
authors.initials: Y
authors.lastname: Li
authors.forename: Renko
authors.initials: R
authors.lastname: de Vries
authors.forename: Ted
authors.initials: T
authors.lastname: Slaghek
authors.forename: Johan
authors.initials: J
authors.lastname: Timmermans
authors.forename: Martien A
authors.initials: MA
authors.lastname: Cohen Stuart
authors.forename: Willem
authors.initials: W
authors.lastname: Norde
mesh_terms: D003432:Cross-Linking Reagents / Q000737:chemistry; D003497:Cyclic N-Oxides / Q000737:chemistry; D003692:Delayed-Action Preparations / Q000737:chemistry*; D004339:Drug Compounding / Q000379:methods*; D005782:Gels / Q000737:chemistry* / Q000627:therapeutic use; D009113:Muramidase / Q000008:administration & dosage; D010084:Oxidation-Reduction; D010316:Particle Size; D011108:Polymers; D011506:Proteins / Q000008:administration & dosage; D013213:Starch / Q000737:chemistry* / Q000627:therapeutic use
chemical_list: D003432:Cross-Linking Reagents; D003497:Cyclic N-Oxides; D003692:Delayed-Action Preparations; D005782:Gels; D011108:Polymers; D011506:Proteins; D013213:Starch; D009113:Muramidase; C003959:TEMPO