Non-invasive evaluation of alginate/poly-L-lysine/alginate microcapsules by magnetic resonance microscopy
2007 (English)In: Biomaterials, ISSN 0142-9612, E-ISSN 1878-5905, Vol. 28, no 15, 2438-2445 p.Article in journal (Refereed) Published
In this report, we present data to demonstrate the utility of H-1 MR microscopy to non-invasively examine alginate/poly-L-lysine/ alginate (APA) microcapsules. Specifically, high-resolution images were used to visualize and quantify the poly-L-lysine (PLL) layer, and monitor temporal changes in the alginate gel microstructure during a month long in vitro culture. The thickness of the alginate/PLL layer was quantified to be 40.6 +/- 6.2 mu m regardless of the alginate composition used to generate the beads or the time of alginate/PLL interaction (2, 6, or 20 min). However, there was a notable difference in the contrast of the PLL layer that depended upon the guluronic content of the alginate and the alginate/PLL interaction time. The T-2 relaxation time and the apparent diffusion coefficient (ADC) of the alginate matrix were measured periodically throughout the month long culture period. Alginate beads generated with a high guluronic content alginate demonstrated a temporal decrease in T-2 over the duration of the experiment, while ADC was unaffected. This decrease in T-2 is attributed to a reorganization of the alginate microstructure due to periodic media exchanges that mimicked a regular feeding regiment for cultured cells. In beads coated with a PLL layer, this temporal decrease in T-2 was less pronounced suggesting that the PLL layer helped maintain the integrity of the initial alginate microstructure. Conversely, alginate beads generated with a high mannuronic content alginate (with or without a PLL layer) did not display temporal changes in either T-2 or ADC. This observation suggests that the microstructure of high mannuronic content alginate beads is less susceptible to culture conditions.
Place, publisher, year, edition, pages
2007. Vol. 28, no 15, 2438-2445 p.
MR imaging, alginate encapsulation, poly-L-lysine
Engineering and Technology
IdentifiersURN: urn:nbn:se:kth:diva-36188DOI: 10.1016/j.biomaterials.2007.01.012ISI: 000245691700007ScopusID: 2-s2.0-33847639336OAI: oai:DiVA.org:kth-36188DiVA: diva2:435125
QC 201108172011-08-172011-07-082011-08-17Bibliographically approved