Fig. 3.

The design and application of (A) nanocomposite hydrogels and (B) micro composite hydrogels for angiogenesis and vasculogenesis. (A) Schematic illustration of the PEGDMA hydrogel patch (orange) in which PEI-PEGDA gels (green) are loaded in multiple micro-pockets and PLGA microparticles (violet) are embedded. (i) Representation of the chemical structure, (ii) bimodal hydrolytic degradation of the PEGDMA hydrogel patch, (iii) mechanism of the sequential molecular release from the PEGDMA hydrogel patch. Rapid VEGF121 (red) release with the degradation of the PEI-PEGDA gel and sustained VEGF165 (black) release from the PLGA microparticles, (iv) Quantified vascular density of chorioallantoic membrane (CAM), and (v) top view of the vasculature of CAM implanted with hydrogel patches. Sample 1 is the CAM implanted with a patch in which VEGF121 was loaded in the PEI-PEGDA gel, and VEGF165 was encapsulated in the PLGA particles embedded in the PEGDMA hydrogel. Sample 2 is the CAM implanted with the gel patch in which VEGF121 and VEGF165 were loaded in the PEI-PEGDA gel. Sample 3 is the CAM implanted with the gel patch in which VEGF121 and VEGF165 were loaded into the PEGDMA hydrogel. Reprinted with permission from Ref. [149]. Copyright 2013, Elsevier. (B) Inorganic strengthened hydrogel membrane for regenerative periosteum along with new vessels sprouting. (i) Fabricating amino-modified MBGNs and GelMA-MBGNs (G-MBGNs), (ii) pure GelMA and staining of CD31 at 8-week post-implantation, (iii) preparing GelMA/MBGNs and staining of CD31 at 8-week post-implantation, and (iv) preparing GelMA-G-MBGNs and staining of CD31 at 8-week post-implantation. The arrows indicate the new blood vessels. Reprinted with permission from Ref. [107]. Copyright 2017, America Chemical Society. (For interpretation of the references to color in this figure legend, the reader is referred to the Web version of this article.)