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Microcapsules provide a microenvironment by improving the protection and delivery of cells and drugs to specific tissue areas, promoting cell integration and tissue regeneration. Effective microcapsules must not only be permeable for micronutrient diffusion but mechanically stable. Alginate hydrogel is one of the commonly used biomaterials for fabricating microcapsules due to its gel-forming ability and low toxicity. However, its mechanical instability, inertness, and excessive porosity have impeded its use. Embedding nanofibrils in the alginate hydrogel microcapsules improves their biological and mechanical properties. In this research, electrospun composite nanofibers of PCL–gelatin (PG) were first fabricated, characterized, and cryoground. The filtered and cryoground powder solution was mixed with the alginate solution and through electrospray, fabricated into microcapsules. Parameters such as flow rate, voltage, and hydrogel composition, which are critical in the electrostatic encapsulation process, were optimized. The microcapsules were further immersed in different solvent environments (DI water, complete media, and PBS), which were observed and compared for their morphology, size distribution, and mechanical stability properties. The average diameters of the PG nanofibers ranged between 0.2 and 2 μm, with an average porosity between 58 and 73%. The average size of the microcapsules varied between 300 and 900 μm, depending on the solvent environment. Overall, results showed an improved alginate 3D hydrogel network suitable for biomedical applications.
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Towards a Consistent Method to Form PEGDA Hydrogel Microcapsules
As part of the PI's outreach, a course-based undergraduate research experience engaged undergraduate women in research from examining the literature to identify a gap, formulating a research hypothesis, designing experiments to test the hypothesis, analyzing the data, writing and submitting an abstract and presenting the research to the scientific community. This project was as follows: Polyethylene glycol (PEG) has increasingly been used to reliably encapsulate cells within solid microspheres. Although hollow microcapsules have also been demonstrated, there remain challenges for their use. Microfluidics can reliably form empty hollow microcapsules, but tend to clog when cells are introduced. Emulsion methods have shown success with encapsulating cells within microcapsules; however the capsules tend to burst. Here, we compare an emulsion technique with our new dropwise method that combines extrusion with vibration of a device. Light exposure and photoinitiator concentration was varied to probe their effect on the microcapsules.
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- Award ID(s):
- 1752079
- PAR ID:
- 10139167
- Date Published:
- Journal Name:
- Biomedical Engineering Society
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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