title: Biocompatibility and surface structure of chemically modified immunoisolating alginate-PLL capsules.
abstract: Grafting of encapsulated living cells has the potential to cure a wide variety of diseases. Large-scale application of the technique, however, is hampered by insufficient biocompatibility of the capsules. A major factor in the biocompatibility of capsules is inadequate covering of the inflammatory poly-L-lysine (PLL) on the capsules' surface. In the present study, we investigate whether tissue responses against alginate-PLL capsules can be reduced by crosslinking the surface of the capsules with heparin or polyacrylic acid. Our transplant study in rats shows a tissue response composed of fibroblasts and macrophages on alginate-PLL-alginate and alginate-PLL-heparin capsules that was completely absent on alginate-PLL-polyacrylic acid capsules. Atomic force microscopy analyses of the capsules demonstrates that the improved biocompatibility of alginate-PLL-capsules by polyacrylic acid coating should not only be explained by a more adequate binding of PLL but also by the induction of a smoother surface. This study shows for the first time that biologic responses against capsules can be successfully deleted by chemically crosslinking biocompatible molecules on the surface of alginate-PLL capsules.
authors: Department of Surgery, University of Rostock, Schillingallee 35, 18055 Rostock, Germany.
authors: C M
authors: CM
authors: Bünger
authors: C
authors: C
authors: Gerlach
authors: T
authors: T
authors: Freier
authors: K P
authors: KP
authors: Schmitz
authors: M
authors: M
authors: Pilz
authors: C
authors: C
authors: Werner
authors: L
authors: L
authors: Jonas
authors: W
authors: W
authors: Schareck
authors: U T
authors: UT
authors: Hopt
authors: P
authors: P
authors: de Vos
mesh_terms: D000180:Acrylic Resins / Q000737:chemistry / Q000378:metabolism; D000464:Alginates / Q000737:chemistry*; D000818:Animals; D002214:Capsules / Q000737:chemistry*; D020099:Coated Materials, Biocompatible / Q000737:chemistry / Q000378:metabolism; D003432:Cross-Linking Reagents / Q000737:chemistry / Q000378:metabolism; D005549:Foreign-Body Reaction; D006493:Heparin / Q000737:chemistry / Q000378:metabolism; D006801:Humans; D008297:Male; D008422:Materials Testing; D018625:Microscopy, Atomic Force; D011107:Polylysine / Q000031:analogs & derivatives* / Q000737:chemistry* / Q000276:immunology*; D051381:Rats; D017208:Rats, Wistar; D013499:Surface Properties
chemical_list: D000180:Acrylic Resins; D000464:Alginates; D002214:Capsules; D020099:Coated Materials, Biocompatible; D003432:Cross-Linking Reagents; C051546:alginate-polylysine-alginate; D011107:Polylysine; C006903:carbopol 940; D006493:Heparin