Adv. mater.: Professor Chen Guoqiang's research group of Tsinghua University prepared "Noah's Ark" of cells by using natural macromolecular material polyhydroxyfatty acid ester to assist stem cell transportation and tissue repair

Recently, Professor Chen Guoqiang's research group of School of life sciences of Tsinghua University published on-line the title of "Noah's Ark of cells: polyhydroxyfatty acid ester open porous microspheres as an injectable scaffold for tissue repair" (a micro ‐ ark for cells: highly open porouspolyhydroxyalkanoate microsphere s as In this work, we designed an open porous microsphere with a diameter of 300-360 μ m by using the biomaterial polyhydroxyalkanoate (PHA) and gas-in-oil-in-water double emulsion technology, OPM) provides a new injectable cell carrier tool for regenerative medicine, minimally invasive surgery and stem cell therapy (DOI: 10.1002 / ADMA 201802273) Pha-opm is a special spherical three-dimensional culture carrier, which has the advantages of good biocompatibility, injectability of microspheres and open three-dimensional structure of tissue engineering scaffolds Its special open porous structure can promote cell growth in vitro; play a supporting role in the process of injection and transportation, protect the cells inside the microspheres from extrusion and friction; and achieve the purpose of cell release and tissue repair in animals Pha-opm is also known as micro Noah's Ark for cells, because its operation process and function are very similar to that of Noah's Ark in the Bible Tissue engineering scaffolds play a key role in tissue medicine and stem cell therapy Stent transplantation with traditional operation is often accompanied by large-scale open surgery and postoperative infection, which directly affects the life of patients Minimally invasive surgery has the advantages of reducing patients' pain, convenient operation and improving clinical safety, which has developed rapidly in recent years Injectable biomaterials, represented by polymer hydrogels and microspheres, are currently the best cell carriers for minimally invasive surgery, but there are also deficiencies In this work, human bone marrow mesenchymal stem cells (hMSCs) were inoculated It was confirmed that the cell inoculation rate of pha-opm was much higher than that of pha-hm, and it could grow continuously By using the Wei frozen ordered section and three-dimensional remodeling technology, we can clearly observe the process of cell migration from the surface to the interior of pha-opm This work further confirmed that the open porous structure of pha-opm can significantly protect most cells from pressure and friction during injection, and also directly affect the results of stem cell differentiation and tissue repair The experimental group using pha-opm as the carrier was much better than the other control groups In addition to the advanced open porous structure, pha-opm also has the advantages of materials Chen Guoqiang's research group has been engaged in the research of microbial synthesis and application of PHA, and its research results have been published in the fields of metabolic engineering, bioplastics, regenerative medicine and tissue engineering, pharmaceutical chemistry, etc A large number of studies show that the biocompatibility of PHA is better than other polyester materials represented by PLA The main reason is that lactic acid, the main degradation product of PLA, is a small acid molecule, which will affect the growth of cells when released in large quantities, while the acid of 3-hydroxybutyrate (3HB), the main degradation product of PHA, is far less than that of lactic acid, which has smaller cell stimulation, and a certain concentration of 3HB can promote cell activity Therefore, due to the rapid release of lactic acid, pla-opm is not as effective as pha-opm in cell proliferation, differentiation in vitro and tissue repair Professor Chen Guoqiang, School of life, Tsinghua University, is the corresponding author of this work Wei Daixu, a CLS doctoral student at Tsinghua University, and Dao Jinwei, a doctoral student at the school of life, are the co authors of this paper This project is supported by NSFC, Tsinghua University Life Science Joint Center, Center for synthesis and systems biology, and supported by biomedical testing center of Tsinghua University, experimental animal center of Tsinghua University and protein facility experimental technology center of Tsinghua University.