Tissue scaffolds with improved delivery of growth factor developed using PLGA-PEG-Mal from PolySciTech

A powerful tool in medicine would be the ability to produce a tissue-scaffold which allows for tissue which has been lost due to disease or trauma to be replaced with fresh stem-cells. There are many barriers to the developemtn of this tool one of which is ensuring that the stem-cells have the appropriate anchoring sites as well as the correct growth factors to ensure their appropriate growth and development. Recently, researchers working jointly at Fudan University (China), Tianjin Medical University (China), Ewha Women’s University (Korea), and University of Michigan utilized Maleimide-PEG-PLGA (PolyVivo AI136) and fluorescently conjugated PLGA-FPR648 (Polyvivo AV008) from PolySciTech (www.polyscitech.com) to generate a scaffold which allowed for controlled release of differentiation factors. They used the developed scaffold to repair ischemic tissue in a mouse model. This research holds promise to enable tissue repair and regeneration by successfully growing differentiated stem-cells into damaged areas. Read more: Li, Ruixiang, Zhiqing Pang, Huining He, Seungjin Lee, Jing Qin, Jian Wu, Liang Pang, Jianxin Wang, and Victor C. Yang. "Drug depot-anchoring hydrogel: A self-assembling scaffold for localized drug release and enhanced stem cell differentiation." Journal of Controlled Release (2017). http://www.sciencedirect.com/science/article/pii/S016836591730706X

“Abstract: Localized and long-term delivery of growth factors has been a long-standing challenge for stem cell-based tissue engineering. In the current study, a polymeric drug depot-anchoring hydrogel scaffold was developed for the sustained release of macromolecules to enhance the differentiation of stem cells. Self-assembling peptide (RADA16)-modified drug depots (RDDs) were prepared and anchored to a RADA16 hydrogel. The anchoring effect of RADA16 modification on the RDDs was tested both in vitro and in vivo. It was shown that the in vitro leakage of RDDs from the RADA16 hydrogel was significantly less than that of the unmodified drug depots (DDs). In addition, the in vivo retention of injected hydrogel-incorporated RDDs was significantly longer than that of hydrogel-incorporated unmodified DDs. A model drug, vascular endothelial growth factor (VEGF), was encapsulated in RDDs (V-RDDs) as drug depot that was then anchored to the hydrogel. The release of VEGF could be sustained for 4 weeks. Endothelial progenitor cells (EPCs) were cultured on the V-RDDs-anchoring scaffold and enhanced cell proliferation and differentiation were observed, compared with a VEGF-loaded scaffold. Furthermore, this scaffold laden with EPCs promoted neovascularization in an animal model of hind limb ischemia. These results demonstrate that self-assembling hydrogel-anchored drug-loaded RDDs are promising for localized and sustained drug release, and can effectively enhance the proliferation and differentiation of resident stem cells, thus lead to successful tissue regeneration. Graphical abstract: Schematic illustration of a vascular endothelial growth factor (VEGF)-loaded RDDs-anchoring hydrogel. The RADA16 peptide is the basic self-assembling unit forming fiber and constructing hydrogel; poly (lactic-co-glycolic acid) (PLGA) based, VEGF-loaded drug depots (DDs) were modified using the RADA16 peptide (V-RDDs) to anchor them to the skeleton of the hydrogel; PEG was applied as a spacer to ensure the full stretch of the RADA16 peptide. VEGF demonstrated sustained release into the hydrogel to enhance the proliferation and differentiation of resident EPCs. Keywords: PLGA; RADA16 hydrogel; Sustained release; Endothelial progenitor cells; Vascular endothelial growth factor; Tissue regeneration”