A novel collagen/hydroxyapatite/poly (lactide‐co‐ε‐caprolactone) biodegradable and bioactive 3D porous scaffold for bone regeneration (original) (raw)
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Journal of Biomedical Materials Research, 2001
Engineering new bone tissue with cells and a synthetic extracellular matrix (scaffolding) represents a new approach for the regeneration of mineralized tissues compared with the transplantation of bone (autografts or allografts). In the present work, highly porous poly(L-lactic acid) (PLLA) and PLLA/hydroxyapatite (HAP) composite scaffolds were prepared with a thermally induced phase separation technique. The scaffolds were seeded with osteoblastic cells and cultured in vitro. In the pure PLLA scaffolds, the osteoblasts attached primarily on the outer surface of the polymer. In contrast, the osteoblasts penetrated deep into the PLLA/HAP scaffolds and were uniformly distributed. The osteoblast survival percentage in the PLLA/HAP scaffolds was superior to that in the PLLA scaffolds. The osteoblasts proliferated in both types of the scaffolds, but the cell number was always higher in the PLLA/HAP composite scaffolds during 6 weeks of in vitro cultivation. Bone-specific markers (mRNAs encoding bone sialoprotein and osteocalcin) were expressed more abundantly in the PLLA/HAP composite scaffolds than in the PLLA scaffolds. The new tissue increased continuously in the PLLA/HAP composite scaffolds, whereas new tissue formed only near the surface of pure PLLA scaffolds. These results demonstrate that HAP imparts osteoconductivity and the highly porous PLLA/ HAP composite scaffolds are superior to pure PLLA scaffolds for bone tissue engineering.
Osteoblast Behavior on Novel Porous Polymeric Scaffolds
Journal of Biomaterials and Tissue Engineering, 2011
Current efforts in bone tissue engineering have as one focus the search for a scaffold material that supports osteoblast proliferation, matrix mineralization, and, ultimately, bone formation. Electrospraying of polymer solutions has enabled the engineering of porous materials to meet current challenges in bone replacement therapies. Porous scaffolds of poly(-caprolactone)/poly(diisopropyl fumarate) compatibilized blend for bone tissue engineering were obtained by electrospraying technique in order to create a better osteophilic environment for the growth and differentiation of osteoblasts. Non-porous films having smooth surface were obtained by casting and used for comparison purposes. Studies on cell-scaffold interaction were carried out by culturing two osteoblastlike cell lines, MC3T3E1 and UMR106, on three-dimensional scaffolds and two-dimensional films. Growth, proliferation, and differentiation (alkaline phosphatase activity) of osteoblasts, were assessed. Scaffolds displayed a highly porous structure with interconnected pores formed by polymer microparticles, and higher hydrophobicity than the observed in non-porous films. The adhesion, proliferation and alkaline phosphatase activity of cells grown on the porous scaffolds increased significantly in comparison to those observed on flat films. The rough surface morphology of this novel scaffold enhances osteoblast response. These results suggest that electrosprayed porous scaffolds may be potentially used as tissue engineering scaffolds with high bone regenerative efficacy.
Synthetic Three-Dimensional Scaffold for Application in the Regeneration of Bone Tissue
Journal of Biomaterials and Nanobiotechnology
Bone tissue engineering aims to use biodegrade able scaffolds to replace damaged tissue. This scaffold must be gradually degraded and replaced by tissue as similar as possible to the original one. In this work a hybrid porous scaffold containing chitosan, polyvinyl alcohol and bioactive glass was successfully obtained and subsequently characterized by scanning electron microscopy. The scaffold presented satisfactory pore size range and open interconnected pores, which are essential for tissue ingrowth. A cytotoxicity assay showed that this biomaterial allows adequate cell viability, so that it was considered suitable for an in vivo experiment. Promising results were obtained with the implant of the scaffold in an experimental model of a New Zealand rabbit femur bone lesion. Clinical and biochemical parameters measured such as complete blood count, total serum proteins, albumin, alanine aminotransferase and aspartate aminotransferase were similar between animals in the control group at all time periods studied. Histological and histometric studies showed that the scaffold was coated with a cement-like substance, exhibiting many areas of mineralized structures. Very few osteocyte-like cells or lining-like cells were found inside the amorphous mineralized deposit. In vivo results allow us to consider this scaffold as a promising biomaterial to be applied in bone tissue engineering.
Porous scaffolds for bone regeneration
Journal of Science: Advanced Materials and Devices, 2020
Globally, bone fractures due to osteoporosis occur every 20 s in people aged over 50 years. The significant healthcare costs required to manage this problem are further exacerbated by the long healing times experienced with current treatment practices. Novel treatment approaches such as tissue engineering, is using biomaterial scaffolds to stimulate and guide the regeneration of damaged tissue that cannot heal spontaneously. Scaffolds provide a three-dimensional network that mimics the extra cellular microenvironment supporting the viability, attachment, growth and migration of cells whilst maintaining the structure of the regenerated tissue in vivo. The osteogenic capability of the scaffold is influenced by the interconnections between the scaffold pores which facilitate cell distribution, integration with the host tissue and capillary ingrowth. Hence, the preparation of bone scaffolds with applicable pore size and interconnectivity is a significant issue in bone tissue engineering. To be effective however in vivo, the scaffold must also cope with the requirements for physiological mechanical loading. This review focuses on the relationship between the porosity and pore size of scaffolds and subsequent osteogenesis, vascularisation and scaffold degradation during bone regeneration.
Journal of the Iranian Chemical Society, 2018
The fabrication of three-dimensional (3D) scaffolds with an optimal pore architecture (e.g., pore size and porosity) that effectively promotes cellular activity on scaffold surfaces is of great interest in bone tissue engineering. In this work, three various 3D hydroxyapatite/poly(D,L)-lactic acid (HAp/PDLLA) scaffolds with different values of HAp to PDLLA in weight percent (0, 10, and 30%) were fabricated by applying a solvent casting-particulate leaching technique. Chloroform was used as a casting solvent to investigate the effects of pore architecture on cellular adhesion, distribution, and proliferation on the fabricated scaffolds. These scaffolds were characterized through field-emission scanning electron microscopy, X-ray diffraction, and liquid substitution to determine their structure, morphological characteristics, pore sizes, and porosity. Cell proliferation, adhesion, and distribution on these scaffolds were evaluated through in vitro tests with human osteoblast MG 63 cell line. Results showed that pore size and porosity greatly affected the proliferation, adhesion, and distribution of MG 63 cells on the fabricated scaffolds. Mean pore sizes ranging from 177 to 245 µm and porosities varying from 76 to 83% were optimal for cell proliferation and adhesion on these scaffolds. Among the fabricated scaffolds, 3D HAp/PDLLA scaffolds with 10% (m/m) HAp to PDLLA exhibited the highest cell adhesion and good cell proliferation capabilities and formed a well-organized cytoskeleton architecture after 7 days of culture. Hence, 3D HAp/PDLLA scaffolds as biomaterials showed potential for bone tissue applications.
Acta Biomaterialia, 2010
Biomimetic composites consisting of polymer and mineral components, resembling bone in structure and composition, were produced using a rapid prototyping technique for bone tissue engineering applications. Solid freeform fabrication, known as rapid prototyping (RP) technology, allows scaffolds to be designed with pre-defined and controlled external and internal architecture. Using the indirect RP technique, a three-component scaffold with a woodpile structure, consisting of poly-l-lactic acid (PLLA), chitosan and hydroxyapatite (HA) microspheres, was produced that had a macroporosity of more than 50% together with micropores induced by lyophilization. X-ray diffraction analysis indicated that the preparation and construction of the composite scaffold did not affect the phase composition of the HA. The compressive strength and elastic modulus (E) for the PLLA composites are 0.42 and 1.46 MPa, respectively, which are much higher than those of chitosan/HA composites and resemble the properties of cellular structure. These scaffolds showed excellent biocompatibility and ability for three-dimensional tissue growth of MC3T3-E1 pre-osteoblastic cells. The pre-osteoblastic cells cultured on these scaffolds formed a network on the HA microspheres and proliferated not only in the macropore channels but also in the micropores, as seen from the histological analysis and electron microscopy. The proliferating cells formed an extracellular matrix network and also differentiated into mature osteoblasts, as indicated by alkaline phosphatase enzyme activity. The properties of these scaffolds indicate that they can be used for non-load-bearing applications.
Acta Biomaterialia, 2008
This work describes the development of a biodegradable matrix, based on chitosan and starch, with the ability to form a porous structure in situ due to the attack by specific enzymes present in the human body (α-amylase and lysozyme). Scaffolds with three different compositions were developed: chitosan (C100) and chitosan/starch (CS80-20, CS60-40). Compressive test results showed that these materials exhibit very promising mechanical properties, namely a high modulus in both the dry and wet states. The compressive modulus in the dry state for C100 was 580 ± 33 MPa, CS80-20 (402 ± 62 MPa) and CS60-40 (337 ± 78 MPa). Degradation studies were performed using α-amylase and/or lysozyme at concentrations similar to those found in human serum, at 37 °C for up to 90 days. Scanning electron micrographs showed that enzymatic degradation caused a porous structure to be formed, indicating the potential of this methodology to obtain in situ forming scaffolds. In order to evaluate the biocompatibility of the scaffolds, extracts and direct contact tests were performed. Results with the MTT test showed that the extracts of the materials were clearly non-toxic to L929 fibroblast cells. Analysis of cell adhesion and morphology of seeded osteoblastic-like cells in direct contact tests showed that at day 7 the number of cells on CS80-20 and CS60-40 was noticeably higher than that on C100, which suggests that starch containing materials may promote cell adhesion and proliferation. This combination of properties seems to be a very promising approach to obtain scaffolds with gradual in vivo pore forming capability for bone tissue engineering applications.
Journal of Biomedical Materials Research Part B: Applied Biomaterials, 2008
Highly porous composites made up of biodegradable poly-e-caprolactone (PCL) and stoichiometric hydroxyapatite (HA) particles have been developed as substrate for bonetissue regeneration. The processing technique consists of phase inversion and particulate (salt crystals) leaching. Three different HA contents (13, 20 and 26 vol %) in PCL-based composite were considered in this study. Pore microstructure with fully interconnected network and pore sizes ranging around a few hundred of lm (macroporosity) was obtained as a result of salt particles removal by leaching process. Several microns (microporosity) porosity was also created through phase inversion of polymer solution. Total porosity up to 95% was achieved. Human marrow stromal cells (MSC) were seeded onto porous PCL-based composites for 1-5 weeks and cultured in osteogenic medium. MSC were able to adhere and grow on PCL-based substrates with a plateau at 3-4 weeks. However, the small effect of bioactive signals on the biological response evaluated in MSC cell culture suggests a prior role of topography on the biological response. Importantly, the presence of HA as a bioactive solid signal determines an increase of mechanical properties. On the overall, the results indicated that porous PCL-based composites are potential candidate for bone substitution with beneficial influence on structural characteristics by solid signal addition. '
One of the critical challenges that scaffolding faces in the organ and tissue regeneration field lies in mimicking the structure, and the chemical and biological properties of natural tissue. A high-level control over the architecture, mechanical properties and composition of the materials in contact with cells is essential to overcome such challenge. Therefore, definition of the method, materials and parameters for the production of scaffolds during the fabrication stage is critical. With the recent emergence of rapid prototyping (RP), it is now possible to create three-dimensional (3D) scaffolds with the essential characteristics for the proliferation and regeneration of tissues, such as porosity, mechanical strength, pore size and pore interconnectivity, and biocompatibility. In this study, we employed 3D bioplotting, a RP technology, to fabricate scaffolds made from (i) pure polycaprolactone (PCL) and (ii) a composite based on PCL and ceramic micro-powder. The ceramics used for the composite were bovine bone filling Nukbone® (NKB), and hydroxyapatite (HA) with 5%, 10% or 20% wt. content. The scaffolds were fabricated in a cellular lattice structure (i.e. meshing mode) using a 0/90°lay down pattern with a continuous contour filament in order to achieve interconnected porous reticular structures. We varied the temperature, as well as injection speed and pressure during the bioplotting process to achieve scaffolds with pore size ranging between 200 and 400 μm and adequate mechanical stability. The resulting scaffolds had an average pore size of 323 μm and an average porosity of 32%. Characterization through ATR-FTIR revealed the presence of the characteristic bands of hydroxyapatite in the PCL matrix, and presented an increase of the intensity of the phosphate and carbonyl bands as the ceramic content increased. The bioplotted 3D scaffolds have a Young's modulus (E) in the range between 0.121 and 0.171 GPa, which is compatible with the modulus of natural bone. PCL/NKB scaffolds, particularly 10NKBP (10% NKB wt.) exhibited the highest proliferation optical density, demonstrating an evident osteoconductive effect when cultured in Dulbecco's Modified Eagle Medium (DMEM). Scanning electron microscopy (SEM) confirmed osteoblast anchorage to all composite scaffolds, but a low adhesion to the all-PCL scaffold, as well as cell proliferation. The results from this study demonstrate the potential of PCL/NKB 3D bioplotted scaffolds as viable platforms to enable osseous tissue formation, which can be used in several tissue engineering applications, including improvement of bone tissue regeneration.