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Comparative Study
. 2010 Nov;200(5):655-8.
doi: 10.1016/j.amjsurg.2010.08.001.

Multilayered microcapsules for the sustained-release of angiogenic proteins from encapsulated cells

Omaditya Khanna  1 , Monica L Moya, Howard P Greisler, Emmanuel C Opara, Eric M Brey
Affiliations
Comparative Study

Multilayered microcapsules for the sustained-release of angiogenic proteins from encapsulated cells

Omaditya Khanna et al. Am J Surg. 2010 Nov.

Abstract

Background: Multilayered alginate microcapsules with a permselective poly-L-ornithine membrane can be used for the dual purpose of encapsulating cells in the inner core and sustained release of angiogenic proteins from the outer layer. The aim of this study was to examine the encapsulation and release of a novel chimeric form of fibroblast growth factor-1 (FGF-1) from the outer layer of alginate microcapsules.

Methods: Heparin-binding growth-associated molecule bound to FGF-1 (HB-GAM/FGF-1) was encapsulated in the outer layer of multilayered alginate microbeads constructed using varying alginate conditions. The encapsulation and release of the chimera was quantified.

Results: The outer layer was able to encapsulate and release HB-GAM/FGF-1 for up to 30 days. The outer layer made with 1% alginate of high mannuronic acid content provided the fastest release, while 1.25% high guluronic acid content alginate displayed the longest duration of release.

Conclusions: The outer layer of multilayered alginate microbeads can be used for the encapsulation and long-term release of HB-GAM/FGF-1.

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Figures

Figure 1
Figure 1
A visual schematic of the concept behind multilayered alginate microbeads. Islets are encapsulated in the inner core, and an angiogenic protein (HB-GAM/FGF-1) in the outer alginate layer. The permselective PLO membrane prevents the diffusion of large molecules such as antibodies, but allows for the exchange of solutes such as glucose, oxygen and insulin. When implanted the protein is released from the outer layer and stimulates neovascaularization towards the bead.
Figure 2
Figure 2
The realease of HB-GAM/FGF-1 from the outer layer of multilayered alginate microbeads varied based on the composition and concentration of alginate used. An initial burst release of HB-GAM/FGF-1 is exhibited for all four groups studied (A), and release at low-levels is continued for up to thirty days (B).
Figure 3
Figure 3
A comparison of the release profiles of FGF-1 with heparin and HB-GAM/FGF-1 encapsulated in alginate microbeads with a 1.25% LVG outer layer. HB-GAM/FGF-1 has a much higher initial burst release than FGF-1, but its continued long-term release that would serve to achieve persistent neovascularization.
See this image and copyright information in PMC

References

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