3D Bioplotter Research Papers

There is an urgent critical need for the development of clinically relevant tissue-engineered large bone substitutes that can promote early vascularization after transplantation. To promote rapid blood vessel growth in the engineered tissue, we preincubated aortic fragments, as well as, co-cultures of aortic fragments and osteoblast-like cells in matrigel-filled PLGA scaffolds before implantation into the dorsal skinfold chambers of balb/c mice. Despite an acceptable and low inflammatory response, preincubated aortic fragments accelerate early angiogenesis of tissue-engineered constructs; the angiogenesis was found to occur faster than that observed in previous studies. Thus, the time-period for achieving a denser microvascular network could…

Aims Rapid blood vessel ingrowth in transplanted tissue engineering constructs is the key factor for successful incorporation, but many potential patients who may use engineered tissues suffer from widespread diseases that limit the capacity of neovascularization (e.g. diabetes). Thus, in vivo vascularization analyses of tissue-engineered constructs in angiogenically affected organisms are required. Methods We therefore investigated the in vivo incorporation of collagen-coated and cell-seeded poly-L-lactide-co-glycolide scaffolds in diabetic B6.BKS(D)-Leprdb/J mice using repetitive intravital fluorescence microscopy over a time period of two weeks. For this purpose, scaffolds were seeded with osteoblast-like or bone marrow mesenchymal stem cells and implanted into the…

In tissue engineering research, generating constructs with an adequate extent of clinical applications remains a major challenge. In this context, rapid blood vessel ingrowth in the transplanted tissue engineering constructs is the key factor for successful incorporation. To accelerate the microvascular development in engineered tissues, we preincubated osteoblast-like cells as well as mesenchymal stem cells or a combination of both cell types in Matrigel-filled PLGA scaffolds before transplantation into the dorsal skinfold chambers of balb/c mice. By the use of preincubated mesenchymal stem cells, a significantly accelerated angiogenesis was achieved. Compared with previous studies that showed a decisive increase of…

Bone marrow derived mesenchymal stem cells (bmMSCs) are widely used for the generation of tissue engineering constructs, since they can differentiate into different cell types occurring in bone tissues. Until now their use for the generation of tissue engineering constructs is limited. All cells inside a tissue engineering construct die within a short period of time after implantation of the construct because vascularization and establishment of connections to the recipient circulatory system is a time consuming process. We therefore compared the influences of bmMSC, VEGF and a combination of both on the early processes of vascularization, utilizing the mice skinfold…

The demanding need for tissue replacement resulted in manifold approaches for the construction of different tissues. One common problem which hampers the clinical usage of tissue engineering constructs is a limited vascularization. In an attempt to accelerate the vascularization of tissue engineering constructs we compared the usage of bone marrow mesenchymal stem cells (bmMSCs) and fragments derived from the aorta in vivo. Tissue engineering constructs composed of PLGA scaffolds containing Matrigel (n = 8), aortic fragments embedded in Matrigel (n = 8), bmMSCs embedded in Matrigel (n = 8), and aortic fragments embedded in Matrigel combined with bmMSCs (n =…

The faith of tissue engineered bone replacing constructs depends on their early supply with oxygen and nutrients, and thus on a rapid vascularization. Although some models for direct observation of angiogenesis are described, none of them allows the observation of new vessel formation in desmal bone. Therefore, we developed a new chamber model suitable for quantitative in vivo assessment of the vascularization of bone substitutes by intravital fluorescence microscopy. In the parietal calvaria of 32 balb/c mice a critical size defect was set. Porous 3D-poly(L-lactide-co-glycolide) (PLGA)-blocks were inserted into 16 osseous defects (groups 3 and 4) while other 16 osseous…

Angiogenic and inflammatory responses to biodegradable scaffolds were previously studied using the dorsal skinfold chamber for testing different scaffold materials. In this model, the angiogenic response originates from the soft tissue of the skin. Herein, we introduce a new model that allows the study of developing microcirculation of bone defects for testing tissue-engineered constructs. A bone defect was prepared in the femur of Balb/c mice by inserting a pin for intramedullary fixation, and a custom-made observation window fixed over the defect allowed constant observation. This study included three different groups: empty defect (control), defect filled with porous poly(l-lactide-co-glycolide), and beta-tricalcium-phosphate…

The implantation of tissue-engineered constructs leads to hypoxic and physical stress to the seeded cells until they were reached by a functional microvascular system. Preconditioning of cells with heat shock induced heat shock proteins, which can support the cells to survive a subsequent episode of stress that would otherwise be lethal. Preconditioning of tissue-engineered constructs resulted in significantly higher number of surviving osteoblast-like cells (OLC). At the 6th and 10th day, angiogenic response was found comparative to poly(L-lactide-co-glycolide) (PLGA) scaffolds vitalized with either unconditioned or preconditioned OLC. However, they were significantly enhanced compared with the nonvitalized collagen-labeled PLGA scaffolds. This…

Background: Bone substitutes should ideally promote rapid vascularization, which could be accelerated if these substitutes were vitalized by autologous cells. Although adequate engraftment of porous poly(L-lactide-co-glycolide) (PLGA) scaffolds has been demonstrated in the past, it has not yet been investigated how vascularization is influenced by vitalization or, more precisely, by seeding PLGA scaffolds with osteoblast-like cells (OLCs). For this reason, we conducted an in vivo study to assess host angiogenic and inflammatory responses after the implantation of PLGA scaffolds vitalized with isogeneic OLCs. Materials and Methods: OLCs were seeded on collagen-coated PLGA scaffolds that were implanted into dorsal skinfold chambers…

Adequate vascularization of tissue-engineered constructs remains a major challenge in bone grafting. In view of this, we loaded ß-tricalcium-phosphate (ß-TCP) and porous poly(L-lactide-co-glycolide) (PLGA) scaffolds via collagen coating with vascular endothelial growth factor (VEGF) and studied whether the VEGF loading improves scaffold angiogenesis and vascularization. Dorsal skinfold chambers were implanted into 48 balb/c mice, which were assigned to 6 groups (n = 8 each). Uncoated (controls), collagen-coated, and additionally VEGF-loaded PLGA and ß-TCP scaffolds were inserted into the chambers. Angiogenesis, neovascularization, and leukocyte-endothelial cell interaction were analyzed repeatedly during a 14-day observation period using intravital fluorescence microscopy. Furthermore, VEGF release…

Implantation of tissue engineering constructs is a promising technique to reconstruct injured tissue. However, after implantation the nutrition of the constructs is predominantly restricted to vascularization. Since cells possess distinct angiogenic potency, we herein assessed whether scaffold vitalization with different cell types improves scaffold vascularization. 32 male balb/c mice received a dorsal skinfold chamber. Angiogenesis, microhemodynamics, leukocyte–endothelial cell interaction and microvascular permeability induced in the host tissue after implantation of either collagen coated poly (l-lactide-co-glycolide) (PLGA) scaffolds (group 4), additionally seeded with osteoblast-like cells (OLCs, group 1), bone marrow mesenchymal stem cells (bmMSCs, group 2) or a combination of OLCs…

Scaffolds for tissue engineering of bone should mimic bone matrix and promote vascular ingrowth. Whether synthetic hydroxyapatite and acellular dentin, both materials composed from calcium phosphate, fulfill these material properties has not been studied yet. Therefore, we herein studied in vivo the host angiogenic and inflammatory response to these biomaterials. Porous scaffolds of hydroxyapatite and isogeneic acellular dentin were implanted into the dorsal skinfold chamber of balb/c mice. Additional animals received perforated implants of isogeneic calvarial bone displaying pores similar in size and structure to those of both scaffolds. Chambers of animals without implants served as controls. Angiogenesis and neovascularization…

In tissue engineering, rapid ingrowth of blood vessels into scaffolds is a major prerequisite for the survival of three-dimensional tissue constructs. In the present study, we investigated whether the vascularization of implanted poly-D,L-lactic-co-glycolic acid (PLGA) scaffolds may be accelerated by incorporation of Matrigel. For this purpose, we investigated in the aortic ring assay the proangiogenic properties of growth factor reduced Matrigel (GFRM) and growth factor containing Matrigel (GFCM), which were then incorporated into the pores of PLGA scaffolds. Subsequently, we analyzed vascularization, biocompatibility, and incorporation of these scaffolds during 14 days after implantation into dorsal skinfold chambers of balb/c mice…

Objective: We analyzed, in vivo, whether the establishment of blood supply to implanted scaffolds can be accelerated by inosculation of an in situ-preformed microvascular network with the host microvasculature. Background: A rapid vascularization is crucial for the survival of scaffold-based transplanted tissue constructs. Methods: Poly-lactic-glycolic acid scaffolds were implanted into the flank of balb/c or green fluorescent protein (GFP)-transgenic mice for 20 days to create in situ a new microvascular network within the scaffolds. The prevascularized scaffolds were then transferred into the dorsal skinfold chamber of isogeneic recipient mice. Nonvascularized poly-lactic-glycolic acid scaffolds served as controls. Vascularization, blood perfusion, and…

For tissue engineering, scaffolds should be biocompatible and promote neovascularization. Because little is known on those specific properties, we herein studied in vivo the host angiogenic and inflammatory response after implantation of commonly used scaffold materials. Porous poly(l-lactide-co-glycolide) (PLGA) and collagen–chitosan–hydroxyapatite hydrogel scaffolds were implanted into dorsal skinfold chambers of balb/c mice. Additional animals received cortical bone as an isogeneic, biological implant, while chambers of animals without implants served as controls. Angiogenesis and neovascularization as well as leukocyte–endothelial cell interaction and microvascular permeability were analyzed over 14 day using intravital fluorescence microscopy. PLGA scaffolds showed a slight increase in leukocyte…