Preparation Of Patterned Composite Fiber Scaffold Loaded With Bioglass Microspheres And Its Application In Diabetic Wounds

Diabetic foot ulcer,a serious complication of diabetes melitus,brings not only enormous pain for patients,but also huge economic burden to the society.Once the patients suffer a break in the skin of their foot,the wound is difficult to heal because of the infection,impaired angiogenesis and oxidative stress.It's urgent to develop a reliable skin tissue engineering scaffold to solve this problem.The electrospun nanofiber scaffold is featured with high specific surface area and porosity which is suitable for the skin tissue engineering.The patterned electrospun nanofiber scaffold farbricated by control the pattern of collector could mimtic the native hierarchical structure of extracellular matrix(ECM),which could provide cells with structure support.In view of the difficult of angiogenesis in diabetic wound healing,the spherical bioactive glass was incorporated into the patterned electrospun scaffold with two different ways.These two novel composite scaffolds could not only mimic the structure native ECM but also can release ions which can promote the angiogenesis and ultimately accelerate the process of diabetic wound healing.The specific work is as follows: 1)The preparation of polydopamine modified patternted electrospun scaffold loaded with spherical bioactive glass and study on its biological properities.The electrospun scaffold was always farbricated with synthetic polymer,which is difficulty to support cell adhesion and proliferation because of its hydrophobic properity.Take this disadvantage into consideration,the patternted electrospun scaffold(PM)was modified with polydopamine(PDA),furthermore,the spherical bioactive glasses were attached on the surface of nanofibers.The in vitro study showed that compared with non-modified patternted scaffold the polydopamine modified patternted scaffold(PDA/PM and BG/PDA/PM)could significantly stimulate the proliferation and attachment of human umbilical vein endothelial cell(HUVECs).Besides,BG/PDA/PM group could promote the cell migration and the expression of angiogenesis-related genes.The in vivo study further demonstrated that the BG/PDA/PM could promote angiogenesis,re-epitheliazation and collagen deposition as well as inhibited inflammatory reaction in the diabetic wound bed,which ultimatly accelerated the process of diabetic wound healing 2)The preparation of BGs loaded co-axial patternted electrospun scaffold and study on its biological properities.According to the above results,the diabetic wound is a chronic wound,which repuire the sustain release of Si ion.So,the co-axial patterned electrospun scaffold was first successfully prepared.The as-prepared nanofibers were core-sheath structured with a BGs loaded synthetical polymer(PLA)core and a natural polymer(gelatin)sheath.The BGs were well distributed in the fibers and the Si ions release was obviously controlled from the scaffold.The in vitro study showed that the patterneted structure as well as the gelatin sheath of the scaffold could significantly stimulation the adhesion and proliferation of HUVECs.Besides,the Si ions released from the scaffold could promote the migration and angiogenesis of HUVECs.The in vivo study further demonstrated that the co-axial patternted composite scaffold could promote angiogenesis,re-epitheliazation and collagen deposition in the diabetic wound bed,which ultimatly accelerated the process of diabetic wound healing.