Fabrication And Biological Characteristics Of Injectable Hydrogel-Poly(L-Polyamino Acid)/Alginic Acid

Objective Tissue engineering technology may be one of the hotspots in the soft tissuedefect repair and reconstruction area in recent years. Good biological material is thekey to the method and injection material is hot for the past few years. The study was aresearch of a novel injectable hydrogel scaffold—PLGA/OAg, for fabrication andperformance characterization in vitro. Biological compatibility and adipogenicdifferentiation in vitro was also discussed via hADSCs cultivated in the scaffold. Andto assess the possibility of constructing tissue engineering adipose tissue.Methods (1) Natural polymer—PLGA was modified, grafting functional groups(-NH2) and Ag was oxidated to form OAg. The chemical crosslinking method wasused to form PLGA/OAg gel, and various solid content of water gel gelling time,degradation rate, swelling and mechanical performance were tested;(2) hADSCs wereisolated from human lipoaspirates and inducted to differentiate toward threelineages(osteogenic, adipogenic, chondrogenic lineages) to identified;(3) hADSCscultivated in the scaffold in vitro, cell growth and adhesion were observed by invertedphase contrast microscope and scanning electron microscopy. The cell proliferationwas tested by DNA quantitative method. LIVE/DEAD VIABILITY kit was used todetect the hADSCs survival in the scaffold;(4) hADSCs cultivated in the scaffold wereadipose-inducted in vitro, then adipose indicated genes was analysed by RT-PCR.hADSCs inducted for a week in vitro composite PLGA/OAg gel scaffold was injectedinto the nude mouse subcutaneous, frozen section and oil red O dye were carried out to identify the generation of adipose tissue.Results (1) The mechanical performance of PLGA/OAg hydrogel show an elasticbehavior,6%of solid content of hydrogel mechanical properties are the strongest,7%of solid content of hydrogel dawolong increase, mechanical properties instead hasdropped. With the increase of the solid content, the PLGA/OAg hydrogel mechanicalproperties strengthen gradually, while swelling ratio down gradually;(2) According toresult of live/dead viability test, cells did not appear large number of death, the ratio of24h dead cells is about3.8%,48h is about9.8%. DNA Quantitative results show thatcells gradually increase and present proliferation trend;(3) hADSCs/gel complex invitro after adipogenic induction, adipose related gene expression was detected byRT-PCR. hADSCs inducted for a week in vitro composite PLGA/OAg gel scaffold wasinjected into the nude mouse subcutaneous, after six weeks, the composite were notcompletely degradated. oil red O dye identified the newly construct tissues as adiposetissue.Conclusion PLGA/OAg has a good3-D pore structure, mechanical properties,swelling ratio,a short gelling time, and can achieve in situ gelling. It has a goodbiocompatibility, the controllability and minimally invasive application advantages.For further development of adipose tissue engineering materials, it is instructive.PLGA/OAg hydrogel composite hADSCs engineered construction adipose tissues, butregeneration quantity need to be further improved.