title: Coating alginate beads with cross-linked biopolymers: a novel method based on a transacylation reaction.
abstract: Stable membranes were formed around alginate beads using a transacylation reaction between polysaccharidic esters, namely propylene glycol alginate (PGA) or pectin, and various proteins (human serum albumin (HSA), ovalbumin, bovine hemoglobin, lactoserum proteins). In a standard procedure, two reagents (PGA or pectin+protein) were added to a Na-alginate solution: beads were formed by dropwise addition into a calcium solution. Then the transacylation reaction was started by alkalinization of the bead suspension. A membrane was formed around the beads, made of a protein directly bound to a polysaccharide through amide linkages. The thickness of the membranes and the lysis time in trypsin were increased by raising the amount of NaOH used for the transacylation step. In a modified procedure, coated beads were obtained, incorporating PGA in the initial Na-alginate solution, and HSA in the transacylation bath. Activated charcoal was encapsulated in HSA-PGA beads, giving particles with adsorption properties towards creatinine. Assays were performed using PGA associated with alkaline phosphatase as the membrane-forming protein. Stable beads were obtained having a relative activity of 39.3%, as compared with free enzyme.
authors.affiliation: Laboratoire de Pharmacotechnie, URA/CNRS N degree 492, Faculté de Pharmacie, Reims, France.
authors.forename: M C
authors.initials: MC
authors.lastname: Levy
authors.forename: F
authors.initials: F
authors.lastname: Edwards-Levy
mesh_terms: D000215:Acylation; D000464:Alginates / Q000737:chemistry*; D000469:Alkaline Phosphatase / Q000737:chemistry; D001704:Biopolymers / Q000737:chemistry*; D002606:Charcoal; D002951:Citrates / Q000032:analysis; D003404:Creatinine / Q000737:chemistry; D003432:Cross-Linking Reagents; D004339:Drug Compounding; D006863:Hydrogen-Ion Concentration; D008567:Membranes, Artificial; D008863:Microspheres; D010368:Pectins; D011409:Propylene Glycols / Q000737:chemistry; D012709:Serum Albumin / Q000737:chemistry
chemical_list: D000464:Alginates; D001704:Biopolymers; D002951:Citrates; D003432:Cross-Linking Reagents; D008567:Membranes, Artificial; D011409:Propylene Glycols; D012709:Serum Albumin; D002606:Charcoal; D010368:Pectins; D003404:Creatinine; D000469:Alkaline Phosphatase