title: Surface analysis of an encapsulation membrane after its implantation in mini-pigs.
abstract: The biocompatibility of membranes aiming at being a part of a bioartificial pancreas has been tested. For that purpose, we have studied a polycarbonate membrane surface after its implantation in mini-pigs. The membranes were made hydrophilic by an argon plasma surface treatment followed by a dipping in a hydrophilic polymer solution. Two polymers were tested: polyvinylpyrrolidone (PVP) and hydroxypropylmethylcellulose (HPMC). To test their biocompatibility, an encapsulation device for pig Langerhans islets, with external membranes treated as described above, was implanted in different mini-pigs. The pigs received no further treatment. The devices were explanted after in vivo exposure and the membranes were analysed by XPS (x-ray photoelectron spectroscopy) and ToF-SIMS (time-of-flight secondary ion mass spectrometry). After this time, the substrate with the PVP or HPMC treatment was still detected on the different samples. The surface treatment signal, however, was attenuated. This is explained by the detection of other components partly covering the surface. XPS and ToF-SIMS analyses revealed the presence of biological molecules on the two faces of the membrane: the outside face in contact with the biological environment and the inside face in contact with the device. ToF-SIMS images show the inhomogeneity of the biological molecules on the membrane surface. In conclusion, biological molecules adhered to the encapsulation membrane surface after implantation but the surface treatments remained unaltered.
authors.affiliation: Université Catholique de Louvain, PCPM, Croix du Sud 1, B1348 Louvain-La-Neuve, Belgium. marie.henry@pcpm.ucl.ac.be
authors.forename: Marie
authors.initials: M
authors.lastname: Henry
authors.forename: Karin
authors.initials: K
authors.lastname: Ulrichs
authors.forename: Vasily
authors.initials: V
authors.lastname: Moskalenko
authors.forename: Michel
authors.initials: M
authors.lastname: Bonneau
authors.forename: Chantal
authors.initials: C
authors.lastname: Kang
authors.forename: Alain
authors.initials: A
authors.lastname: Belcourt
authors.forename: Patrick
authors.initials: P
authors.lastname: Bertrand
mesh_terms: D000818:Animals; D001672:Biocompatible Materials / Q000009:adverse effects* / Q000737:chemistry*; D005549:Foreign-Body Reaction / Q000209:etiology* / Q000473:pathology*; D020007:Implants, Experimental / Q000009:adverse effects*; D008297:Male; D008422:Materials Testing; D008567:Membranes, Artificial; D011076:Polycarboxylate Cement / Q000009:adverse effects* / Q000737:chemistry; D013499:Surface Properties; D013552:Swine; D013556:Swine, Miniature
chemical_list: D001672:Biocompatible Materials; D008567:Membranes, Artificial; D011076:Polycarboxylate Cement; C005506:polycarbonate