3D Bioplotter Research Papers

Displaying all papers about in-vivo (mice) (39 results)

Angiogenic effects of mesenchymal stem cells in combination with different scaffold materials

Microvascular Research 2019

Tissue survival in regenerative tissue engineering requires rapid vascularization, which is influenced by scaffold material and seeded cell selection. Poly-l-lactide-co-glycolide (PLGA) and beta-tricalcium phosphate (β-TCP) are well-established biomaterials with angiogenic effects because of their material properties. Given the importance of the seeded cell type as a co-factor for vascularization, mesenchymal stem cells (MSCs) are known to have high angiogenic potential. We hypothesized that PLGA and β-TCP scaffolds seeded with MSCs would effectively induce a potent angiogenic response. Therefore, we studied the angiogenic effects after implanting PLGA and β-TCP scaffolds seeded with isogeneic MSCs in vivo. Fifty-six BALB/c mice were equally…

Silicone resin derived larnite/C scaffolds via 3D printing for potential tumor therapy and bone regeneration

Chemical Engineering Journal 2019

Three dimensional (3D) printing has been used to fabricate bioceramic scaffolds for treating the tumor-related defects in recent years, but the fabrication process and the introduction of anti-tumor agents are still challenging. In this study, porous free carbon-embedding larnite (larnite/C) scaffolds have been successfully fabricated by 3D printing of the silicone resin loaded with CaCO3 filler and high temperature treatment under an inert atmosphere. The fabricated larnite/C scaffolds had uniform interconnected macropores (ca. 400 μm), and exhibited excellent photothermal effect, which was able to kill human osteosarcoma cells (MNNG/HOS) and inhibit the tumor growth in nude mice. Moreover, the larnite/C scaffolds…

Suturable regenerated silk fibroin scaffold reinforced with 3D-printed polycaprolactone mesh: biomechanical performance and subcutaneous implantation

Journal of Materials Science: Materials in Medicine 2019 Volume 30, Article 63

The menisci have crucial roles in the knee, chondroprotection being the primary. Meniscus repair or substitution is favored in the clinical management of the meniscus lesions with given indications. The outstanding challenges with the meniscal scaffolds include the required biomechanical behavior and features. Suturability is one of the prerequisites for both implantation and implant survival. Therefore, we proposed herein a novel highly interconnected suturable porous scaffolds from regenerated silk fibroin that is reinforced with 3D-printed polycaprolactone (PCL) mesh in the middle, on the transverse plane to enhance the suture-holding capacity. Results showed that the reinforcement of the silk fibroin scaffolds…

Bacterial cellulose nanofibers promote stress and fidelity of 3D-printed silk based hydrogel scaffold with hierarchical pores

Carbohydrate Polymers 2019 Volume 221, Pages 146-156

One of the latest trends in the regenerative medicine is the development of 3D-printing hydrogel scaffolds with biomimetic structures for tissue regeneration and organ reconstruction. However, it has been practically difficult to achieve a highly biomimetic hydrogel scaffolds with proper mechanical properties matching the natural tissue. Here, bacterial cellulose nanofibers (BCNFs) were applied to improve the structural resolution and enhance mechanical properties of silk fibroin (SF)/gelatin composite hydrogel scaffolds. The SF-based hydrogel scaffolds with hierarchical pores were fabricated via 3D-printing followed by lyophilization. Results showed that the tensile strength of printed sample increased significantly with the addition of BCNFs in…

3D printing of mesoporous bioactive glass/silk fibroin composite scaffolds for bone tissue engineering

Materials Science & Engineering C 2019 Volume 103, Article 109731

The fabrication of bone tissue engineering scaffolds with high osteogenic ability and favorable mechanical properties is of huge interest. In this study, a silk fibroin (SF) solution of 30 wt% was extracted from cocoons and combined with mesoporous bioactive glass (MBG) to fabricate MBG/SF composite scaffolds by 3D printing. The porosity, compressive strength, degradation and apatite forming ability were evaluated. The results illustrated that MBG/SF scaffolds had superior compressive strength (ca. 20 MPa) and good biocompatibility, and stimulated bone formation ability compared to mesoporous bioactive glass/polycaprolactone (MBG/PCL) scaffolds. We subcutaneously transplanted hBMSCs-loaded MBG/SF and MBG/PCL scaffolds into the back of nude mice…

3D Bioprinted Scaffolds Containing Viable Macrophages and Antibiotics Promote Clearance of Staphylococcus aureus Craniotomy-Associated Biofilm Infection

ACS Apllied Materials & Interfaces 2019 Volume 11, Issue 13, Pages 12298-12307

Craniotomy involves the removal of a skull fragment to access the brain, such as during tumor or epilepsy surgery, which is immediately replaced intraoperatively. The infection incidence after craniotomy ranges from 0.8 to 3%, with approximately half caused by Staphylococcus aureus (S. aureus). To mitigate infectious complications following craniotomy, we engineered a three-dimensional (3D) bioprinted bone scaffold to harness the potent antibacterial activity of macrophages (MΦs) together with antibiotics using a mouse S. aureus craniotomy-associated biofilm model that establishes a persistent infection on the bone flap, subcutaneous galea, and brain. The 3D scaffold contained rifampin and daptomycin printed in a…

3D-printable self-healing and mechanically reinforced hydrogels with host–guest non-covalent interactions integrated into covalently linked networks

Materials Horizons 2019

Natural polymer hydrogels are one of the best biomaterials for soft tissue repair because of their excellent biocompatibility, biodegradability and low immune rejection. However, they lack mechanical strength matching that of natural tissue and desired functionality (e.g., self-healing and 3D-printability). To solve these problems, we developed a host–guest supramolecule (HGSM) with three arms covalently crosslinked with a natural polymer to construct a novel hydrogel with non-covalent bonds integrated into a covalently crosslinked network. This unique structure enabled the hydrogel to exhibit improved mechanical properties and show both self-healing and 3D printing capabilities. The three-armed HGSM was first prepared via efficient…

Homogeneous hydroxyapatite/alginate composite hydrogel promotes calcified cartilage matrix deposition with potential for three-dimensional bioprinting

Biofabrication 2019 Volume 11, Issue 1, Article 015015

Calcified cartilage regeneration plays an important role in successful osteochondral repair, since it provides a biological and mechanical transition from the unmineralized cartilage at the articulating surface to the underlying mineralized bone. To biomimic native calcified cartilage in engineered constructs, here we test the hypothesis that hydroxyapatite (HAP) stimulates chondrocytes to secrete the characteristic matrix of calcified cartilage. Sodium citrate (SC) was added as a dispersant of HAP within alginate (ALG), and homogeneous dispersal of HAP within ALG hydrogel was confirmed using sedimentation tests, electron microscopy, and energy dispersive spectroscopy. To examine the biological performance of ALG/HAP composites, chondrocyte survival…

3D-printed IFN-γ-loading calcium silicate-β-tricalcium phosphate scaffold sequentially activates M1 and M2 polarization of macrophages to promote vascularization of tissue engineering bone

Acta Biomaterialia 2018 Volume 71, Pages 96-107

To promote vascularization of tissue-engineered bone, IFN-γ polarizing macrophages to M1 was loaded on 5% calcium silicate/β-tricalcium phosphate (CaSiO3-β-TCP) scaffolds. IFN-γ and Si released from the scaffold were designed to polarize M1 and M2 macrophages, respectively. β-TCP, CaSiO3-β-TCP, and IFN-γ@CaSiO3-β-TCP were fabricated and biocompatibilities were evaluated. Polarizations of macrophages were detected by flow cytometry. Human umbilical vein endothelial cells with GFP were cultured and induced on Matrigel with conditioned culture medium extracted from culture of macrophages loaded on scaffolds for evaluating angiogenesis. Four weeks after the scaffolds were subcutaneously implanted into C57B1/6, vascularization was evaluated by visual observation, hematoxylin and…

Elastic polyurethane bearing pendant TGF-β1 affinity peptide for potential tissue engineering applications

Materials Science and Engineering: C 2017 Volume 83, Pages 67-77

Highlights * An elastic degradable polyurethane (PU) bearing pendent HSNGLPL peptide for TGF-β1 affinity binding mimics the extracellular matrix function to retain and release growth factors. * The pendant peptide sequence presented a high affinity for TGF-β1 retaining, even when the surface was pre-coated with other proteins. * The synthesized PU shows good extrusion processing ability and can be printed into 3D scaffolds with designed porous structures. * The released TGF-β1 from surface conjugating was tested by differentiation guiding experiments of ATDC5 cells in vitro and the regeneration of the surrounding tissue after implanting in vivo.

Prevascularization of 3D printed bone scaffolds by bioactive hydrogels and cell co-culture

Journal of Biomedical Materials Research Part B: Applied Biomaterials 2017 Volume 106B, Pages 1788–1798

Vascularization is a fundamental prerequisite for large bone construct development and remains one of the main challenges of bone tissue engineering. Our current study presents the combination of 3D printing technique with a hydrogel-based prevascularization strategy to generate prevascularized bone constructs. Human adipose derived mesenchymal stem cells (ADMSC) and human umbilical vein endothelial cells (HUVEC) were encapsulated within our bioactive hydrogels, and the effects of culture conditions on in vitro vascularization were determined. We further generated composite constructs by forming 3D printed polycaprolactone/hydroxyapatite scaffolds coated with cell-laden hydrogels and determined how the co-culture affected vascularization and osteogenesis. It was demonstrated…

Short-term hypoxic preconditioning promotes prevascularization in 3D bioprinted bone constructs with stromal vascular fraction derived cells

RSC Advances 2017 Volume 7, Pages 29312-29320

Reconstruction of complex, craniofacial bone defects often requires autogenous vascularized bone grafts, and still remains a challenge today. In order to address this issue, we isolated the stromal vascular fraction (SVF) from adipose tissues and maintained the phenotypes and the growth of endothelial lineage cells within SVF derived cells (SVFC) by incorporating an endothelial cell medium. We 3D bioprinted SVFC within our hydrogel bioinks and conditioned the constructs in either normoxia or hypoxia. We found that short-term hypoxic conditioning promoted vascularization-related gene expression, whereas long-term hypoxia impaired cell viability and vascularization. 3D bioprinted bone constructs composed of polycaprolactone/hydroxyapatite (PCL/HAp) and…

A bioprosthetic ovary created using 3D printed microporous scaffolds restores ovarian function in sterilized mice

Nature Communications 2017 Volume 88, Article number 15261

Emerging additive manufacturing techniques enable investigation of the effects of pore geometry on cell behavior and function. Here, we 3D print microporous hydrogel scaffolds to test how varying pore geometry, accomplished by manipulating the advancing angle between printed layers, affects the survival of ovarian follicles. 30° and 60° scaffolds provide corners that surround follicles on multiple sides while 90° scaffolds have an open porosity that limits follicle–scaffold interaction. As the amount of scaffold interaction increases, follicle spreading is limited and survival increases. Follicle-seeded scaffolds become highly vascularized and ovarian function is fully restored when implanted in surgically sterilized mice. Moreover,…

Traditional invasive and synchrotron-based non-invasive assessments of 3D-printed hybrid cartilage constructs

Tissue Engineering Part C: Methods 2017 Volume 23, Issue 3, Pages 156-168

Three-dimensional (3D)-printed constructs made of polycaprolactone (PCL) and chondrocyte-impregnated alginate hydrogel (hybrid cartilage constructs) mimic the biphasic nature of articular cartilage, offering promise for cartilage tissue engineering (CTE) applications. However, the regulatory pathway for medical device development requires validation of such constructs through in vitro bench tests and in vivo preclinical examinations premarket approval. Furthermore, non-invasive imaging techniques are required for effective evaluation of the progress of these cartilage constructs, especially when implanted in animal models or human subjects. However, characterization of the individual components of the hybrid cartilage constructs and their associated time-dependent structural changes by currently available non-invasive…

Pyrintegrin Induces Soft Tissue Formation by Transplanted or Endogenous Cells

Scientific Reports 2017 Issue 7, Article number: 36402

Focal adipose deficiency, such as lipoatrophy, lumpectomy or facial trauma, is a formidable challenge in reconstructive medicine, and yet scarcely investigated in experimental studies. Here, we report that Pyrintegrin (Ptn), a 2,4-disubstituted pyrimidine known to promote embryonic stem cells survival, is robustly adipogenic and induces postnatal adipose tissue formation in vivo of transplanted adipose stem/progenitor cells (ASCs) and recruited endogenous cells. In vitro, Ptn stimulated human adipose tissue derived ASCs to differentiate into lipid-laden adipocytes by upregulating peroxisome proliferator-activated receptor (PPARγ) and CCAAT/enhancer-binding protein-α (C/EBPα), with differentiated cells increasingly secreting adiponectin, leptin, glycerol and total triglycerides. Ptn-primed human ASCs seeded…

Hyperelastic “bone”: A highly versatile, growth factor–free, osteoregenerative, scalable, and surgically friendly biomaterial

Science Translational Medicine 2016 Volume 8, Issue 358, Pages 358ra127

Despite substantial attention given to the development of osteoregenerative biomaterials, severe deficiencies remain in current products. These limitations include an inability to adequately, rapidly, and reproducibly regenerate new bone; high costs and limited manufacturing capacity; and lack of surgical ease of handling. To address these shortcomings, we generated a new, synthetic osteoregenerative biomaterial, hyperelastic “bone” (HB). HB, which is composed of 90 weight % (wt %) hydroxyapatite and 10 wt % polycaprolactone or poly(lactic-co-glycolic acid), could be rapidly three-dimensionally (3D) printed (up to 275 cm3/hour) from room temperature extruded liquid inks. The resulting 3D-printed HB exhibited elastic mechanical properties (~32…

Osteogenic Differentiation of Three-Dimensional Bioprinted Constructs Consisting of Human Adipose-Derived Stem Cells In Vitro and In Vivo

PloS One 2016 Volume 11, Issue 6, e0157214

Here, we aimed to investigate osteogenic differentiation of human adipose-derived stem cells (hASCs) in three-dimensional (3D) bioprinted tissue constructs in vitro and in vivo. A 3D Bio-plotter dispensing system was used for building 3D constructs. Cell viability was determined using live/dead cell staining. After 7 and 14 days of culture, real-time quantitative polymerase chain reaction (PCR) was performed to analyze the expression of osteogenesis-related genes (RUNX2, OSX, and OCN). Western blotting for RUNX2 and immunofluorescent staining for OCN and RUNX2 were also performed. At 8 weeks after surgery, osteoids secreted by osteogenically differentiated cells were assessed by hematoxylin-eosin (H&E) staining,…

Accelerated vascularization of tissue engineering constructs in vivo by preincubated co-culture of aortic fragments and osteoblasts

Biochemical Engineering Journal 2016 Volume 105, Part A, Pages 230–241

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…

[Osteogenesis of human adipose-derived mesenchymal stem cells-biomaterial mixture in vivo after 3D bio-printing]

Journal of Peking University. Health Sciences 2016 Volume 48, Issue 1, Pages 45-50

To construct human adipose-derived mesenchymal stem cells (hASCs)-biomaterial mixture 3D bio-printing body and detect its osteogenesis in vivo, and to establish a guideline of osteogenesis in vivo by use of 3D bio-printing technology preliminarily.P4 hASCs were used as seed cells, whose osteogenic potential in vitro was tested by alkaline phosphatase (ALP) staining and alizarin red staining after 14 d of osteogenic induction. The cells were added into 20 g/L sodium alginate and 80 g/L gelatin mixture (cell density was 1×10(6)/mL), and the cell-sodium alginate-gelatin mixture was printed by Bioplotter 3D bio-printer (Envision company, Germany), in which the cells’survival rate was…

Three Dimensional Printing of High-Content Graphene Scaffolds for Electronic and Biomedical Applications

ACS Nano 2015 Volume 9, Issue 4, Pages 4636–4648

The exceptional properties of graphene enable applications in electronics, optoelectronics, energy storage, and structural composites. Here we demonstrate a 3D printable graphene (3DG) composite consisting of majority graphene and minority polylactide-co-glycolide, a biocompatible elastomer, 3D-printed from a liquid ink. This ink can be utilized under ambient conditions via extrusion-based 3D printing to create graphene structures with features as small as 100 μm composed of as few as two layers (10 cm thick object). The resulting 3DG material is mechanically robust and flexible while retaining electrical conductivities greater than 800 S/m, an order of magnitude increase over previously reported 3D-printed carbon…

Decelerated vascularization in tissue-engineered constructs in association with diabetes mellitus in vivo

Journal of Diabetes and its Complications 2015 Volume 29, Issue 7, Pages 855–864

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…

Accelerating the early angiogenesis of tissue engineering constructs in vivo by the use of stem cells cultured in matrigel

Journal of Biomedical Materials Research Part A 2014 Volume 102, Issue 6, Pages 1652–1662

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…

Three-Dimensional Printed Multiphase Scaffolds for Regeneration of Periodontium Complex

Tissue Engineering Part A 2014 Volume 20, Issue 7-8, Pages 1342-1351

Tooth-supporting periodontium forms a complex with multiple tissues, including cementum, periodontal ligament (PDL), and alveolar bone. In this study, we developed multiphase region-specific microscaffolds with spatiotemporal delivery of bioactive cues for integrated periodontium regeneration. Polycarprolactione-hydroxylapatite (90:10 wt%) scaffolds were fabricated using three-dimensional printing seamlessly in three phases: 100-μm microchannels in Phase A designed for cementum/dentin interface, 600-μm microchannels in Phase B designed for the PDL, and 300-μm microchannels in Phase C designed for alveolar bone. Recombinant human amelogenin, connective tissue growth factor, and bone morphogenetic protein-2 were spatially delivered and time-released in Phases A, B, and C, respectively. Upon 4-week in…

In vivo screening of extracellular matrix components produced under multiple experimental conditions implanted in one animal

Integrative Biology 2013 Volume 5, Pages 889-898

Animal experiments help to progress and ensure safety of an increasing number of novel therapies, drug development and chemicals. Unfortunately, these also lead to major ethical concerns, costs and limited experimental capacity. We foresee a coercion of all these issues by implantation of well systems directly into vertebrate animals. Here, we used rapid prototyping to create wells with biomaterials to create a three-dimensional (3D) well-system that can be used in vitro and in vivo. First, the well sizes and numbers were adjusted for 3D cell culture and in vitro screening of molecules. Then, the functionality of the wells was evaluated…

Additive effect of mesenchymal stem cells and VEGF to vascularization of PLGA scaffolds

Microvascular Research 2013 Volume 90, Pages 71–79

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…

In vivo acute and humoral response to three-dimensional porous soy protein scaffolds

Acta Biomaterialia 2013 Volume 9, Issue 11, Pages 8983–8990

Increasing interest in using soy biomaterials for tissue engineering applications has prompted investigation into the in vivo biocompatibility of soy implants. In this study, the biocompatibility of soy protein scaffolds fabricated using freeze-drying and 3-D printing was assessed using a subcutaneous implant model in BALB/c mice. The main objectives of this study were: (1) to compare soy protein with bovine collagen, a well-characterized natural protein implant, by implanting scaffolds of the same protein weight, and (2) to observe the effects of soy scaffold microstructure and amount of protein loading, which also alters the degradation properties, on the acute and humoral…

The effect of scaffold-cell entrapment capacity and physico-chemical properties on cartilage regeneration

Biomaterials 2013 Volume 34, Issue 17, Pages 4259–4265

An important tenet in designing scaffolds for regenerative medicine consists in mimicking the dynamic mechanical properties of the tissues to be replaced to facilitate patient rehabilitation and restore daily activities. In addition, it is important to determine the contribution of the forming tissue to the mechanical properties of the scaffold during culture to optimize the pore network architecture. Depending on the biomaterial and scaffold fabrication technology, matching the scaffolds mechanical properties to articular cartilage can compromise the porosity, which hampers tissue formation. Here, we show that scaffolds with controlled and interconnected pore volume and matching articular cartilage dynamic mechanical properties,…

Comparably accelerated vascularization by preincorporation of aortic fragments and mesenchymal stem cells in implanted tissue engineering constructs

Journal of Biomedical Materials Research Part A 2011 Volume 97A, Issue 4, Pages 383-394

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 =…

Hierarchical scaffold design for mesenchymal stem cell-based gene therapy of hemophilia B

Biomaterials 2011 Volume 32, Issue 1, Pages 295-305

Gene therapy for hemophilia B and other hereditary plasma protein deficiencies showed great promise in pre-clinical and early clinical trials. However, safety concerns about in vivo delivery of viral vectors and poor post-transplant survival of ex vivo modified cells remain key hurdles for clinical translation of gene therapy. We here describe a 3D scaffold system based on porous hydroxyapatite-PLGA composites coated with biomineralized collagen 1. When combined with autologous gene-engineered factor IX (hFIX) positive mesenchymal stem cells (MSCs) and implanted in hemophilic mice, these scaffolds supported long-term engraftment and systemic protein delivery by MSCs in vivo. Optimization of the scaffolds…

Calvaria bone chamber-A new model for intravital assessment of osseous angiogenesis

Journal of Biomedical Materials Research Part A 2011 Volume 99A, Issue 2, pages 151-157

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…

A Novel Approach for Studying Microcirculation in Bone Defects by Intravital Fluorescence Microscopy

Tissue Engineering Part C: Methods 2011 Volume 17, Issue 12, Pages 1151-1159

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…

Prolongated Survival of Osteoblast-Like Cells on Biodegradable Scaffolds by Heat Shock Preconditioning

Tissue Engineering Part A 2011 Volume 17, Issue 15-16, Pages 1935-1943

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…

Accelerated Angiogenic Host Tissue Response to Poly(L-Lactide-co-Glycolide) Scaffolds by Vitalization with Osteoblast-like Cells

Tissue Engineering Part A 2010 Volume 16, Issue 7, Pages 2265-2279

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…

Effects of VEGF loading on scaffold-confined vascularization

Journal of Biomedical Materials Research Part A 2010 Volume 95A, Issue 3, Pages 783-792

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…

Consequences of seeded cell type on vascularization of tissue engineering constructs in vivo

Microvascular Research 2009 Volume 78, Issue 2, Pages 180-190

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…

Vascularization and biocompatibility of scaffolds consisting of different calcium phosphate compounds

Journal of Biomedical Materials Research Part A 2008 Volume 86A, Issue 4, Pages 1002-1011

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…

Incorporation of growth factor containing Matrigel promotes vascularization of porous PLGA scaffolds

Journal of Biomedical Materials Research Part A 2008 Volume 85A, Issue 2, Pages 397-407

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…

Improvement of Vascularization of PLGA Scaffolds by Inosculation of In Situ-Preformed Functional Blood Vessels With the Host Microvasculature

Annals of Surgery 2008 Volume 248 - Issue 6 - Pages 939-948

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…

Angiogenic and inflammatory response to biodegradable scaffolds in dorsal skinfold chambers of mice

Biomaterials 2006 Volume 27, Issue 29, Pages 5027-5038

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…