Structural surface changes and inflammatory responses against alginate-based microcapsules after exposure to human
Bart J de Haan1, Alessandra Rossi, Marijke M Faas
1Department of Pathology and Medical Biology, University Medical Center Groningen, Groningen, The Netherlands. B.J.de.Haan@MED.UMCG.NL
Journal of Biomedical Materials Research. Part A
|June 2, 2011
Summary
Alginate microcapsules undergo surface changes in human peritoneal fluid, potentially increasing inflammatory responses. Biocompatibility testing should include exposure to site fluid to predict in vivo performance.
Area of Science:
- Biomaterials Science
- Immunology
- Cell Encapsulation Technology
Background:
- Cell microencapsulation offers a path to immune tolerance, avoiding immunosuppression.
- Clinical use is limited by incomplete understanding of human capsule biocompatibility.
- Alginate-based capsules are widely studied for cell therapy applications.
Purpose of the Study:
- To investigate the impact of human peritoneal fluid on alginate capsule surface properties.
- To assess how these changes affect capsule biocompatibility and immune cell response.
- To determine alginate-type dependency of surface modifications and inflammatory potential.
Main Methods:
- Exposure of alginate beads and alginate-poly-L-lysine (PLL) capsules to human peritoneal fluid.
- Analysis of surface physicochemical changes using micro-Fourier Transform Infrared Spectroscopy (µFTIR).
- Evaluation of capsule permselectivity and inflammatory cytokine (TNFα) production by peripheral blood mononuclear cells (PBMCs).
Main Results:
- All tested alginate capsule formulations showed adsorption of peritoneal fluid components and surface changes.
- Surface modifications were dependent on the type of alginate used.
- While permselectivity remained unaffected, alginate beads exposed to peritoneal fluid significantly increased TNFα production by PBMCs; alginate-PLL capsules did not exhibit this effect.
Conclusions:
- Alginate capsule surfaces consistently change upon exposure to human peritoneal fluid.
- These surface alterations can enhance inflammatory responses, impacting biocompatibility.
- Biocompatibility assessments must include pre-exposure to implantation site fluid for accurate in vivo prediction.
