Critical-sized bone defects remain challenging in the clinical setting. Autologous bone grafting remains preferred by clinicians. However, the use of autologous tissue is associated with donor-site morbidity and limited accessibility to the graft tissue. Advances in the development of synthetic bone substitutes focus on improving their osteoinductive properties. Whereas osteoinductivity has been demonstrated with ceramics, it is still a challenge in case of polymeric composites. One of the approaches to improve the regenerative properties of biomaterials, without changing their synthetic character, is the addition of inorganic ions with known osteogenic and angiogenic properties. We have previously reported that the use of a bioactive composite with high ceramic content composed of poly(ethyleneoxide terephthalate)/poly(butylene terephthalate) (1000PEOT70PBT30, PolyActive, PA) and 50% beta-tricalcium phosphate (β-TCP) with the addition of zinc in a form of a coating of the TCP particles can enhance the osteogenic differentiation of human mesenchymal stromal cells (hMSCs) (3). To further support the regenerative properties of these scaffolds, inorganic ions with known angiogenic properties, copper or cobalt, were added to the coating solution. β-TCP particles were immersed in a zinc and copper or zinc and cobalt solution with a concentration of 15 or 45 mM. 3D
The regenerative capacity of hyaline cartilage is greatly limited. To prevent the onset of osteoarthritis, cartilage defects have to be properly treated. Cartilage, tissue engineered by mean of bioactive glass (BG) scaffolds presents a promising approach. Until now, conventional BGs have been used mostly for bone regeneration, as they are able to form a hydroxyapatite (HA) layer and are therefore, less suited for cartilage reconstruction. The aim of this study is to compare two BGs based on a novel BG composition tailored specifically for cartilage (CAR12N) and patented by us with conventional BG (BG1393) with a similar topology. The highly
The in vitro mimicking of bone microenvironment for the study of pathologies is a challenging field that requires the design of scaffolds with suitable morphological, structural and cytocompatible properties. During last years, 3D in vitro tumour models have been developed to reproduce mechanical, biochemical and structural bone microenvironment elements, allowing cells to behave as in vivo. In this work, gas foamed polyether urethane foams (PUF) and 3D printed thermoplastic polyether urethane (3DP-PU) designed with different patterns are proposed as scaffolds for in vitro model of bone tissue. Surface coatings for a biomimetic behaviour of the 3D scaffold models were also investigated. Morphological, chemico-physical, mechanical properties, and biological in vitro behaviour were investigated. PUFs for metastases investigation. The suitability of PUF as 3D in vitro model to study the interactions between bone tumour initiating cells and the bone microenvironment was investigated. PUF open porosity (>70%) appeared suitable to mimic trabecular bone structure. Human adipose derived stem cells (ADSC) were cultured and differentiated into osteoblast lineage on the PU foam, as confirmed by Alizarin Red staining and RT-PCR, thus offering a bone biomimetic microenvironment to the further co-culture with bone derived tumour-initiating cells (MCFS). Tumour aggregates were observed after three weeks of co-culture by e-cadherin staining and SEM; modification in CaP distribution was identified by SEM-EDX and associated to the presence of tumour cells. 3DP-PU as tumour bone model. 3D printed scaffolds have pores with a precise and regular geometry (0°-90°, 0°-45°-90°-135°, 0°-60°-120°). PU scaffold porosity evidenced values from 55 to 67%, values that belong to the porosity range of the trabecular bone tissue (30-90%). The compressive modulus varied between 2 and 4 MPa, depending on the printed pattern. Biomimetic nanostructured coating was performed on 0-90° 3DP-PU by Ionized Jet Deposition. Coatings had a submicrometric thickness, variable tuning deposition time, nanostructured surface morphology and biomimetic composition. Coating on 3DP-PU promoted cells colonization of the whole
We developed a new
Abstract. Objectives. Direct ink writing (DIW) has gained considerable attention in production of personalized medical implants. Laponite nanoclay is added in polycaprolactone (PCL) to improve printability and bioactivity for bone implants. The 3D structure of DIW printed PCL/Laponite products was qualitatively evaluated using micro-CT. Methods. PCL/LP composite ink was formulated by dissolving 50% m/v PCL in dichloromethane with Laponite loading of up to 30%. The rheological properties of the inks were determined using Discovery HR-2 rheometer. A custom-made direct ink writer was used to fabricate both
One of the latest trends in the field of tissue engineering is the development of in vitro 3D systems mimicking the target tissue or organ and thus recapitulating the tridimensional structure and microenvironment experienced by cells in vivo. Interestingly, certain tissues are known to be regulated by endogenous bioelectrical cues, in addition to chemical and mechanical cues. One such tissue is the bone. It has, indeed, been demonstrated to exhibit piezoelectric properties in vivo, with electrical signaling playing a role in its formation during the early embryo developmental stages. Electrical stimulation has been proven to sustain cell proliferation and to boost the expression of relevant genes and induce higher levels of enzymatic activities related to bone matrix deposition. Herein, we describe the development of a 3D model of bone tissue based on the conductive polymer PEDOT:PSS and human adipose derived stem cells. 3D electroactive
Calcium phosphates-based coatings have been widely studied to favour a firm bonding between orthopaedic implants and the host bone. To this aim, thin films (thickness below 1 μm) having high adhesion to the substrate and a nanostructured surface texture are desired, capable of boosting platelet, proteins and cells adhesion. In addition, a tunable composition is required to resemble as closely as possible the composition of mineralized tissues and/or to intentionally substitute ions having possible therapeutic functions. The authors demonstrated nanostructured films having high surface roughness and a composition perfectly resembling the deposition target one can be achieved by Ionized Jet Deposition (IJD). Highly adhesive nanostructured coatings were obtained by depositing bone-apatite like thin films by ablation of deproteinized bovine bone, capable of promoting host cells attachment, proliferation and differentiation. Here, biomimetic films are deposited by IJD, using biogenic and synthetic apatite targets. Since IJD deposition can be carried out without heating the substrate, application on heat sensitive polymeric substrate, i.e. 3D printed
The aim of this study is to print 3D polycaprolactone (PCL) scaffolds at high and low temperature (HT/LT) combined with salt leaching to induced porosity/larger pore size and improve material degradation without compromising cellular activity of printed scaffolds. PCL solutions with sodium chloride (NaCl) particles either directly printed in LT or were casted, dried, and printed in HT followed by washing in deionized water (DI) to leach out the salt. Micro-Computed tomography (Micro-CT) and scanning electron microscope (SEM) were performed for morphological analysis. The effect of the porosity on the mechanical properties and degradation was evaluated by a tensile test and etching with NaOH, respectively. To evaluate cellular responses, human bone marrow-derived mesenchymal stem/stromal cells (hBMSCs) were cultured on the scaffolds and their viability, attachment, morphology, proliferation, and osteogenic differentiation were assessed. Micro-CT and SEM analysis showed that porosity induced by the salt leaching increased with increasing the salt content in HT, however no change was observed in LT. Structure thickness reduced with elevating NaCl content. Mass loss of scaffolds dramatically increased with elevated porosity in HT. Dog bone-shaped specimens with induced porosity exhibited higher ductility and toughness but less strength and stiffness under the tension in HT whereas they showed decrease in all mechanical properties in LT. All scaffolds showed excellent cytocompatibility. Cells were able to attach on the surface of the scaffolds and grow up to 14 days. Microscopy images of the seeded scaffolds showed substantial increase in the formation of extracellular matrix (ECM) network and elongation of the cells. The study demonstrated the ability of combining 3D printing and particulate leaching together to fabricate
All types of regenerative materials, including metal implants,
The ideal bone substituting biomaterials should possess bone-mimicking mechanical properties; have of porous interconnected structure, and adequate biodegradation behaviour to enable full recovery of bony defects. Direct metal printed
Abstract. Objectives. Assess and characterise the suitability of a novel silk reinforced biphasic 3D printed scaffold for osteochondral tissue regeneration. Methods. Biphasic hybrid scaffolds consisted of 3D printed poly(ethylene glycol)-terephthalate-poly(butylene terephthalate)(PEGT/PBT) scaffold frame work (pore size 0.75mm), which has been infilled with a cast and freeze dried
Due to its avascular nature, articular cartilage exhibits a very limited capacity to regenerate and to repair. Although much of the engineered cartilage grafts so far proposed have successfully shown to mimic the morphological and biochemical appearance of hyaline cartilage, they are generally mechanically inferior to the natural tissue. 1. In this study a new bioreactor device was realized to test innovative scaffolds under physiological stimulation (i.e. perfusion fluid flow and dynamic compression), with the aim to produce a more functional engineered tissue construct for articular applications. The computer-controlled bioreactor system has been properly designed to simultaneously provide static or dynamic compression and/or continuous perfusion to 3D engineered constructs, reproducing the physiological loads to which the articular cartilage is subjected. The specifically designed bioreactor comprises a chamber where the grafts are accommodated, a porous piston connected to a linear stepper motor (Dings, Model 34-2080-4-300), which controls its movement to provide mechanical stimulation and a peristaltic pump (Watson-Marlow, Model 323S), connected by joints and pipes to the culture chamber to ensure a continuous media perfusion. As piston for compression, a sintered stainless steel filter (43% of porosity) was adopted to allow the perfusion of the culture media during physical stimulation. The culture chamber is composed by a hollow cylinder (30 mm × 40,5 mm) and a base realized as a single object. They are made in polycarbonate for its characteristics of transparency and infrangibility and linked to a Nylon cover through four brass tie rods unscrewable from above. The chamber has been designed to accommodate simultaneously different constructs of any size and shape and stimulate them with perfusion and/or dynamic compression. A finites elements program was used to mimic the effects of perfusion and compression regime on the scaffolds cultured within the bioreactor chamber. The bioreactor was properly designed and developed. Particular attention has been paid to the implementation of a simple, compact and economical system. It was then tested by using different polymeric
Bone remodelling is mediated through the synchronism of bone resorption (catabolism) by osteoclasts and bone formation (anabolism) by osteoblasts. Imbalances in the bone remodelling cycle represent an underling cause of metabolic bone diseases such as osteoporosis, where bone resorption exceeds formation (1). Current therapeutic strategies to repair osteoporotic bone fractures focus solely in targeting anabolism or supressing catabolism (2). However, these therapeutics do not reverse the structural damage present at the defect site, ultimately leading to impaired fracture healing, making the repair of osteoporotic fractures particularly challenging in orthopaedics. Herein, we focus on investigating a combined versatile pro-anabolic and anti-catabolic effect of Magnesium (Mg. 2+. ) to modulate bone cell behaviour (3), to develop an engineered biomimetic bio-instructive biomaterial scaffold structurally designed to enhance bone formation while impeding pathological osteoclast resorption activities to facilitate better bone healing and promote repair. Pre-osteoblasts MC3T3-E1 (OBs) and osteoclasts progenitors RAW 264.7 (OCs) cell lines were cultured in growth media exposed to increasing concentrations of MgCl. 2. (0, 0.5, 1, 10, 25 and 50mM) and the optimal concentration to concurrently promote the differentiation of OBs and inhibit the differentiation or funtion of RANKL-induced OCs was assessed. We next used Fluorescence Lifetime Imaging Microscopy to investigate changes in the metabolic pathways during OBs and OCs differentiation when exposed to increasing MgCl. 2. concentrations. We developed a range of magnesium-incorporated collagen scaffolds to permit the spatiotemporal release of Mg. 2+. within the established therapeutic window, and to investigate the behaviour of bone cells in a 3D environment. In our results, we reported an increase in the expression of the bone formation markers osteocalcin and osteopontin for OBs exposed to 10mM MgCl. 2. , and a significant downregulation of the osteoclast-specific markers TRAP and cathepsin K in RANKL-induced OCs differentiation when exposed to 25mM MgCl. 2. Moreover, 25mM MgCl. 2. induced changes in the energy metabolism of OCs from a predominantly oxidative phosphorylation towards a more glycolytic pathway suggesting a regulatory effect of Mg. 2+. in the underlying mechanisms of osteoclasts formation and function. The developed
Short Summary. The present study demonstrated the feasibility of culturing a large number of standardised granular MSC-containing constructs in a packed bed/column bioreactor that can produce sheep MSC-containing constructs to repair critical-size bone defects in sheep model. Introduction. Endogenous tissue regeneration mechanisms do not suffice to repair large segmental long-bone defects. Although autologous bone graft remains the gold standard for bone repair, the pertinent surgical technique is limited. Tissue constructs composed of MSCs seeded onto biocompatible scaffolds have been proposed for repairing bone defects and have been established in clinically-relevant animal models. Producing tissue constructs for healing bone defects of clinically-relevant volume requires a large number of cells to heal an approximately 3 cm segmental bone defect. For this reason, a major challenge is to expand cells from a bone marrow aspirate to a much larger, and sufficient, number of MSCs. In this respect, bioreactor systems which provide a reproducible and well-controlled three-dimensional (3D) environment suitable for either production of multiple or large size tissue constructs are attractive approaches to expand MSCs and obtain MSC-containing constructs of clinical grade. In these bioreactor systems, MSCs loaded onto scaffolds are exposed to fluid flow, a condition that provides both enhanced access to oxygen and nutrients as well as fluid-flow-driven mechanical stimulation to cells. The present study was to evaluate bioreactor containing autologous MSCs loaded on coral scaffolds to repair critical-size bone defects in sheep model. Materials and Methods. Animals: 12 two-year-old, female Pre-Alpes sheep were used and reared in accordance with the European Committee for Care. Three-dimensional,
Summary. Coating of titanium implants with BMP-2-loaded polyelectrolyte multilayer films conferred the implant surface with osteoinductive properties which are fully preserved upon both air-dried storage and γ-sterilization. Although BMP-2 is recognised as an important molecule for bone regeneration, its supraphysiological doses currently used in clinical practice has raised serious concerns about cost-effectiveness and safety issues. Thus, there is a strong motivation to engineer new delivery systems or to provide already approved materials with new functionalities. Immobilizing the growth factor onto the surface of implants would reduce protein diffusion and increase residence time at the implantation site. To date, modifying the surfaces of metal materials, such as titanium or titanium alloys, at the nanometer scale for achieving dependable, consistent and long-term osseointegration remains a challenging approach. In this context, we have developed an osteoinductive coating of a porous titanium implant using biomimetic polyelectrolyte multilayer (PEM) films used as carriers of BMP-2. The PEM films were prepared by alternate deposition of 24 layer pairs of poly(L-lysine) (PLL) and hyaluronic acid (HA) layers (∼3.5 µm in thickness); such films were then cross-linked by means of a water-soluble carbodiimide (EDC) at different degrees. The amount of BMP-2 loaded in these films was tuned (ranging from 1.4 to 14.3 µg/cm. 2. ) depending on the cross-linking extent of the film and of the BMP-2 initial concentration. Because packaging, and storage of the devices are important issues that may limit a wide application of biologically functionalised materials, we assessed in the present study the osteoinductive performance of the BMP-2 loaded PEM coatings onto custom-made 3D
Scaffold-based bone tissue engineering holds great promise for the future of osseous defects therapies. Prepare the suitable scaffold properties are physiochemical modifications in terms of porosity, mechanical strength, cell adhesion, biocompatibility, cell proliferation, mineralization and osteogenic differentiation are required. We produce various bone tissue scaffolds with different techniques such as lyophilization, 3D printing and electrospinning. We wish to overview all the different novel scaffold methods and materials. To improve scaffolds poor mechanical properties, while preserving the porous structure, it is possible to coat the scaffold with synthetic or natural polymers. An increasing interest in developing materials in bone tissue engineering is directed to the organic/inorganic composites that mimic natural bone. Specifically, bone tissue is a composite of an organic and inorganic matrix. Using PLLA, loofah, chitin and cellulose biomaterials we produced bone tissue scaffold with lyophilization technique. Also, using fish scale powder and wet electrospun Poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV) a sponge structure had created. Using MRI image data and 3D printer method, a bone tissue scaffold is created by PLA filament. Their mechanical properties had analysed with compression tests and their biocompatibilities had investigated. In order to provide novel strategies for future treatment of bone tumours, the properties of the scaffold, including its in vitro extended-release properties, the inhibition effects of chemotherapeutic agent on the bone tumours and its bone repair capacities were investigated in vitro by using MG63 cells. To develop chemotherapeutic agent-encapsulated poly(lactic-co-glycolic acid) (PLGA) nanoparticles in a
ONFH with large or lateral-located lesion is challenging due to difficulty of regeneration. We introduce novel tissue engineering technique using ex vivo expanded bone marrow stromal cell seeded on calcium metaphosphate (CMP) scaffold to regenerate dead bone for these challenging cases. Ten millilitres of bone marrow was aspirated from iliac crest and mononuclear cells were collected. These cells were expanded and differentiated to osteoblast-lineage cells using osteogenic media and autologous serum for 2–4 weeks ex vivo.
Current strategy for orthopedic tissue engineering mainly focusses on the regeneration of the damaged tissue using cell-seeded three-dimensional scaffolds. Biocompatible scaffolds with controllable degradation and suitable mechanical property are required to support new tissue in-growth and regeneration . [1].
Introduction. This study investigated the binding agent Calcium/Sodium Alginate fibre gel and the addition of autogenic bone marrow aspirate (BMA) on bone growth into a
We sought to determine if a durable bilayer implant composed of trabecular metal with autologous periosteum on top would be suitable to reconstitute large osteochondral defects. This design would allow for secure implant fixation, subsequent integration and remodeling. Adult sheep were randomly assigned to one of three groups (n = 8/group): 1. trabecular metal/periosteal graft (TMPG), 2. trabecular metal (TM), 3. empty defect (ED). Cartilage and bone healing were assessed macroscopically, biochemically (type II collagen, sulfated glycosaminoglycan (sGAG) and double-stranded DNA (dsDNA) content) and histologically.Objectives
Materials and Methods