Application Of GelMA-ADM Bioscaffolds In Tissue Engineering Based On Vascularized 3D Printing Strateg

BackgroundBy integrating different biomaterials,3D bioprinting technology is able to create constructs with complex biological and mechanical properties,which can mimic the structure,composition,and function of natural tissues and assist in the repair of damaged tissues/organs.It is an emerging technology in the field of tissue engineering.Hydrogel is a three-dimensional polymer structure,which is widely used as a scaffold in the field of tissue engineering,as a carrier of bioactive substances or cells.At present,the commonly used hydrogels in 3D biological printing include gelatin,methacrylate acylated gelatin(GelMA),extracellular matrix(ECM),etc.Each hydrogel has its advantages and disadvantages.Adipose derived stem cells(ASCs)are adult stem cells derived from fat and possess pluripotency.Under certain culture conditions,it can differentiate into bone,fat and cartilage,and is the seed cell of regenerative medicine.The physical properties of different hydrogels,such as hardness,porosity and viscosity,can be controlled by changing the preparation conditions,chemical composition and crosslinking degree of gel.And these changes in physical and chemical properties will further affect the biological behavior of host cells.Our research is based on 3D biological printing technology,with the use of selfmade GelMA-Acellular dermal matrix(ADM)composite hydrogel,the application of 3D printing construct composed of ASCs in the field of tissue engineering is evaluated.MethodsIn this study,a method to prepare GelMA-ADM composite hydrogel was established,and its physical and chemical characterization was preliminarily evaluated.The concentration ratio of GelMA and ADM was adjusted to explore the effects of different ratios on the cell behavior(proliferation,activity,pluripotency,paracrine ability,etc.)of ASCs,in order to obtain optimized biological ink components.ResultsA method to prepare the GelMA-ADM composite hydrogel was successfully developed and the physical and chemical properties of the hydrogel was revealed.The freeze-dried ADM and GelMA exhibit highly porous structures.The average pore size of the two biological inks decreases with increasing concentration.The process of 3D bioprinting will not disrupt the stemness of ASCs.The results of cell survival experiment showed that the hydrogels with different components could ensure the survival rate of cells to reach more than 90%,and the hydrogels with different components would affect the proliferation of cells.For osteogenic differentiation induction,5%GelMA-30 is the optimal biological ink for conditions.For adipogenic differentiation induction,10%GelMA-60 is the optimal bio ink for conditions.For chondrogenic differentiation induction,5%GelMA-60 is the optimal biological ink for conditions.The addition of ADM on the basis of GelMA has a promoting effect on the paracrine ability of ASCs.ConclusionADM retains good three-dimensional structure and biochemical components on the basis of removing cell components.The fabrication of GelMA-ADM composite hydrogel is promising.GelMA-ADM composite hydrogel scaffold provides a suitable environment for ASCs’ attachment,proliferation,differentiation and other cell behaviors,and provides a research basis for the future application of ASCs’ 3D bioprinting construct in tissue engineering and organ transplantation.BackgroundThe vascular network is crucial for maintaining the normal physiological function of tissues.In modern medicine,the use of 3D printing technology to manufacture vascularized constructs has become a new research hot spot.3D printing technology can accurately control the shape and size of the construct to achieve tissue regeneration and repair.At the same time,by dropping out the bioink blended with cells,complex vascular networks can be generated,thereby achieving tissue vascularization.The interaction between human umbilical vein endothelial cells(HUVECs)and adipose derived stem cells(ASCs)can enhance their natural angiogenesis ability.A prevascularized 3D bioprinting construct consisting of HUVECs and ASCs not only meets the requirements of rapid vascularization after transplantation,but also meets the needs of tissue and organ defect repair.MethodsIn this study,GelMA+ADM composite hydrogel blended with ASCs and gelatin blended with HUVECs were used as bioinks.A 3D printing construct based on a versatile pre-vascularized printing strategy was established.After inducing differentiation in vitro(osteogenic,adipogenic,and chondrogenic)of ASCs for 14 days,they were heterotopic implanted subcutaneously in nude mice.Eight weeks later,vascular perfusion imaging and histopathology analysis were performed on the implanted tissue to explore whether the implanted construct successfully formed new blood vessels,and whether the implanted construct successfully differentiated into target tissue after implantation.ResultsFirstly,a 3D printing construct based on a versatile pre-vascularized printing strategy was successfully established.It was a void-free construct with interconnected channels inside.With HUVECs attached to the wall of GelMA+ADM composite hydrogel,"in situ endothelialization" was achieved.Fluorescent vascular perfusion showed that a stable blood supply was formed after 8 weeks post-implantation.Histopathology experiments showed that the 3D graft could form mature bone,fat or cartilage tissue in the subcutaneous tissue of nude mice.ConclusionThe 3D printing construct based on a versatile pre-vascularized printing strategy can effectively form new blood vessels in vivo,and successfully differentiate into bone tissue,adipose tissue,and cartilage tissue.At the same time,its structure is stable,and it has huge potential application value in the field of organ repair and reconstruction.