title: Attachment of alginate microcapsules onto plasma-treated PDMS sheet for retrieval after transplantation.
abstract: Although transplantation of microencapsulated islets has been proposed as a therapy for the treatment of diabetes mellitus, limited retrievability of the cells has impeded its medical usage. To achieve retrieval of microencapsulated islets, capsules were attached to polydimethylsiloxane (PDMS) with a biocompatible adhesive. Because the hydrophobic nature of the PDMS surface prevents attachment, surface modification is essential. Alginate microcapsules were attached to modified PDMS sheets, and the mechanical stability of the resulting constructs was determined. Acrylic acid (AA) and acrylamide (AM) mixtures were grafted on the surfaces of PDMS sheets using a two-step oxygen plasma treatment (TSPT). TSPT-PDMS was characterized according to water contact angle and zeta-potential measurements. The contact angle was altered by changing the ratio of AM to AA to generate hydrophilic surface. Evaluation of the surface charge at pH 2, 7, and 12 confirmed the presence of polar groups on the modified surface. Microcapsules were attached to TSPT-PDMS using Histoacryl® and shown to be in a monolayered and half-exposed state. The shear stress resistance of alginate capsules attached to the PDMS sheet indicates the possibility of transplantation of encapsulated cells without scattering in vivo. This method is applicable to retrieve microencapsulated porcine islets when required.
authors.affiliation: School of Chemical and Biological Engineering, Seoul National University, Seoul, Korea.
authors.forename: Soojeong
authors.initials: S
authors.lastname: Shin
authors.forename: Jeong Eun
authors.initials: JE
authors.lastname: Shin
authors.forename: Young Je
authors.initials: YJ
authors.lastname: Yoo
mesh_terms: D000464:Alginates / Q000737:chemistry*; D000818:Animals; D002214:Capsules; D004129:Dimethylpolysiloxanes / Q000737:chemistry*; D004337:Drug Carriers / Q000737:chemistry*; D020723:Glucuronic Acid / Q000737:chemistry; D006603:Hexuronic Acids / Q000737:chemistry; D057927:Hydrophobic and Hydrophilic Interactions; D016381:Islets of Langerhans Transplantation; D010100:Oxygen / Q000737:chemistry; D058626:Plasma Gases / Q000737:chemistry*; D033081:Shear Strength; D013314:Stress, Mechanical; D013552:Swine
chemical_list: D000464:Alginates; D002214:Capsules; D004129:Dimethylpolysiloxanes; D004337:Drug Carriers; D006603:Hexuronic Acids; D058626:Plasma Gases; C013830:baysilon; D020723:Glucuronic Acid; D010100:Oxygen
keywords: PDMS; alginate microcapsule; cell encapsulation; islet encapsulation; microcapsule attachment; retrieval after transplantation