Multilayer capsules: a promising microencapsulation system for transplantation of pancreatic islets

Autor: Stephan Schneider, Rainer Pommersheim, Jürgen Beyer, Peter J. Feilen, Simon Preuss, Svend Berger, Viola Slotty, Daniel Kampfner
Rok vydání: 2001
Předmět:
Transplantation
Heterotopic
Materials science
Compressive Strength
Biocompatibility
Alginates
Drug Compounding
Acrylic Resins
Islets of Langerhans Transplantation
Biophysics
Biocompatible Materials
Bioengineering
Permeability
Rats
Sprague-Dawley
Biomaterials
chemistry.chemical_compound
Biopolymers
Glucuronic Acid
Materials Testing
medicine
Animals
Polyethyleneimine
Polylysine
Particle Size
Muscle
Skeletal
Acrylic resin
Cells
Cultured
Hexuronic Acids
Pancreatic islets
Biomaterial
Capsule
Prostheses and Implants
Fibrosis
Microspheres
Rats
Quaternary Ammonium Compounds
Transplantation
medicine.anatomical_structure
Membrane
chemistry
Rats
Inbred Lew
Mechanics of Materials
Carboxymethylcellulose Sodium
visual_art
Ceramics and Composites
visual_art.visual_art_medium
Female
Polyethylenes
Biomedical engineering
Zdroj: Biomaterials. 22:1961-1970
ISSN: 0142-9612
DOI: 10.1016/s0142-9612(00)00380-x
Popis: In 1980, Lim and Sun introduced a microcapsule coated with an alginate/polylysine complex for encapsulation of pancreatic islets. Characteristic to this type of capsule is, that it consists of a plain membrane which is formed during a single procedural step. With such a simple process it is difficult to obtain instantly a membrane optimized with respect to all the properties requested for islet transplantation. To overcome these difficulties, it is recommended to build up the membrane in several consecutive steps, each optimized for a certain property. In this study, we have analysed such a multilayer microcapsule for the encapsulation of pancreatic islets. Therefore, empty and islet containing alginate beads were coated with alternating layers of polyethyleneimine, polyacrylacid or carboxymethylcellulose and alginate. By scanning electron microscopy the thickness of the covering multilayer-membrane was estimated to be less than 800 nm by comparison with an apparatus scale. Ellipsometric measurements showed that the membrane thickness is in the range of 145 nm. Neither the encapsulation procedure, nor the membrane-forming step did impede the stimulatory response of the islets. The encapsulation even lead to a significantly better stimulatory response of the encapsulated islets during week three and five of cell culture. Furthermore, the multilayer-membrane did not deteriorate the biocompatibility of the transplanted microcapsules, allowing an easy tuning of the molecular cut-off and the mechanical stability depending on the polycation-polyanion combination used. The multilayer membrane capsule has obvious advantages compared to a one-step encapsulation procedure. These beads guarantee a high biocompatibility, a precisely adjusted cut-off, an optimal insulin-response and high mechanical stability although the membrane is only 145 nm thick.
Databáze: OpenAIRE
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