Development of Biomimetic and Bioactive 3D Nanocomposite Scaffolds for Osteochondral Regeneration (original) (raw)
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Biomimetic biphasic 3-D nanocomposite scaffold for osteochondral regeneration
AIChE Journal, 2013
Due to the disparity in composition and mechanical properties of the osteochondral interface, tissue engineering approaches to the regenration of the osteochondral site face unique challenges that are both biochemical and mechanical in nature. The current work has developed a novel biomimetic biphasic nanocomposite osteochondral scaffold integrating two biocompatible polymers each containing tissue-specific growth factor-encapsulated core-shell nanospheres. Specifically, a poly(caprolactone) based bone layer was successfully integrated with a poly(ethylene glycol) hydrogel cartilage layer. The current work also developed a novel nanosphere fabrication technique for efficient growth factor encapsulation and sustained delivery via wet co-axial electrospray. Human bone marrow mesenchymal stem cell adhesion, osteogenic and chondrogenic differentiation were evaluated in our constructs and showed significantly improved hMSC adhesion and differentiation in vitro.
Polymers
The aim of this study was to report the fabrication of porous scaffolds with pre-designed internal pores using a fused deposition modeling (FDM) method. Polycaprolactone (PCL) is a suitable material for the FDM method due to the fact it can be melted and has adequate flexural modulus and strength to be formed into a filament. In our study, the filaments of methoxy poly(ethylene glycol)-block-poly(ε-caprolactone) having terminal groups of carboxylic acid were deposited layer by layer. Raw materials having a weight ratio of hydroxyapatite (HAp) to polymer of 1:2 was used for FDM. To promote cell adhesion, amino groups of the Arg-Gly-Asp(RGD) peptide were condensed with the carboxylic groups on the surface of the fabricated scaffold. Then the scaffold was infiltrated with hydrogel of glycidyl methacrylate hyaluronic acid loading with 10 ng/mL of TGF-β1 and photo cross-linked on the top of the scaffolds. Serious tests of mechanical and biological properties were performed in vitro. HAp was found to significantly increase the compressive strength of the porous scaffolds. Among three orientations of the filaments, the lay down pattern 0 • /90 • scaffolds exhibited the highest compressive strength. Fluorescent staining of the cytoskeleton found that the osteoblast-like cells and stem cells well spread on RGD-modified PEG-PCL film indicating a favorable surface for the proliferation of cells. An in vivo test was performed on rabbit knee. The histological sections indicated that the bone and cartilage defects produced in the knees were fully healed 12 weeks after the implantation of the TGF-β1 loaded hydrogel and scaffolds, and regenerated cartilage was hyaline cartilage as indicated by alcian blue and periodic acid-schiff double staining.
Journal of Tissue Engineering and Regenerative Medicine, 2013
Osteochondral lesions require treatment to restore the biology and functionality of the joint. A novel nanostructured biomimetic gradient scaffold was developed to mimic the biochemical and biophysical properties of the different layers of native osteochondral structure. The present results show that the scaffold presents important physicochemical characteristics and can support the growth and differentiation of mesenchymal stromal cells (h-MSCs), which adhere and penetrate into the cartilaginous and bony layers. H-MSCs grown in chondrogenic or osteogenic medium decreased their proliferation during days 14-52 on both scaffold layers and in medium without inducing factors used as controls. Both chondrogenic and osteogenic differentiation of h-MSCs occurred from day 28 and were increased on day 52, but not in the control medium. Safranin O staining and collagen type II and proteoglycans immunostaining confirmed that chondrogenic differentiation was specifically induced only in the cartilaginous layer. Conversely, von Kossa staining, osteocalcin and osteopontin immunostaining confirmed that osteogenic differentiation occurred on both layers. This study shows the specific potential of each layer of the biomimetic scaffold to induce chondrogenic or osteogenic differentiation of h-MSCs. These processes depended mainly on the media used but not the biomaterial itself, suggesting that the local milieu is fundamental for guiding cell differentiation.
International journal of molecular sciences, 2018
Articular cartilage is a structure lack of vascular distribution. Once the cartilage is injured or diseased, it is unable to regenerate by itself. Surgical treatments do not effectively heal defects in articular cartilage. Tissue engineering is the most potential solution to this problem. In this study, methoxy poly(ethylene glycol)-block-poly(ε-caprolactone) (mPEG-PCL) and hydroxyapatite at a weight ratio of 2:1 were mixed via fused deposition modeling (FDM) layer by layer to form a solid scaffold. The scaffolds were further infiltrated with glycidyl methacrylate hyaluronic acid loading with 10 ng/mL of Transforming Growth Factor-β1 and photo cross-linked on top of the scaffolds. An in vivo test was performed on the knees of Lanyu miniature pigs for a period of 12 months. The healing process of the osteochondral defects was followed by computer tomography (CT). The defect was fully covered with regenerated tissues in the control pig, while different tissues were grown in the defect...
Applied Materials Today, 2020
Mesenchymal stem cells (MSCs) are considered to be important cell sources for tissue regeneration. Growth factors (GFs) are key mediators of MSCs chondrogenesis and osteogenesis in the enhancement of osteochondral repair. However, uncontrolled delivery and release of these bioactive factors may reduce their bioavailability and lead to off-target side effects. In this study, tri-layered scaffolds, based on the chondrocyte extracellular matrix, nano-hydroxyapatite and silk fibroin were prepared by imitating the structural layers of the osteochondral unit. Particularly, tri-layered scaffolds were functioned for the local and sustained release of transforming growth factor-3 to the chondral layer and bone morphogenetic protein-2 to the bony layer. In conjunction with engrafted human umbilical cord mesenchymal stem cells (hUCMSCs), osteochondral regeneration was enhanced. In vitro experiments indicated that scaffolds supported hUCMSCs proliferation, vitality and adhesion, and facilitated hUCMSCs lineage differentiation toward chondrocytes or osteoblasts, dependent on stimulation by sustained GFs release, at chondral layer or bony layer, respectively. Furthermore, evaluation of osteochondral repair in vivo after 8-and 16-weeks post-implantation indicated that the tri-layered scaffolds with sustained release function and hUCMSC delivery significantly accelerated the repair of large-size osteochondral defects, compared with other scaffolds. In summary, our studies showed that tri-layered scaffolds with the biomimetic structure of osteochondral unit, with sustained GFs release and seeded with hUCMSCs were more conducive to osteochondral regeneration, providing new materials and strategies for tissue engineering for the repair large-scale osteochondral defects.
Novel Nano-composite Multilayered Biomaterial for Osteochondral Regeneration
The American Journal of Sports Medicine, 2011
Background: In recent years, there has been an increasing interest in and awareness of the importance of subchondral bone, for its role in the pathogenesis of articular surface damage and for the care that should be taken when treating such damage.Purpose: The objective of this pilot clinical study was to test the safety and performance of a newly developed type I collagen-hydroxyapatite nanostructured biomimetic osteochondral scaffold that aims to regenerate cartilage and subchondral bone.Study Design: Case series; Level of evidence, 4.Methods: A multilayer gradient nano-composite scaffold was obtained by nucleating collagen type I fibrils with hydroxyapatite nanoparticles. Thirty patients (9 female, 21 male; mean age, 29.3 years) with knee chondral or osteochondral lesions were treated with scaffold implantation. Lesion size varied from 1.5 cm2to 6.0 cm2. Twenty-eight patients were followed for 2 years and were clinically evaluated using the International Knee Documentation Commit...
Inorganic-organic hybrid scaffolds for osteochondral regeneration
Journal of Biomedical Materials Research Part A, 2010
Ligament graft failure frequently results from poor integration of the replacement tissue with associated bone. Thus, the ability to regenerate the bone-ligament osteochondral interface would be advantageous in ligament reconstruction. At the osteochondral interface, the tissue transitions from a bone-like matrix to fibrocartilage. Therefore, a scaffold which promotes a spatially regulated transition in cell behavior from osteoblast-like to chondrocyte-like would be desirable. Previous research indicates that addition of inorganic components to organic scaffolds can enhance the deposition of bone-like matrix by associated osteoblasts. We therefore reasoned that a gradient in the inorganic content of a hybrid inorganic–organic scaffold may induce an osteochondral-like transition in cell phenotype and matrix production. To test this hypothesis, hydrogels were prepared from poly(ethylene glycol) (PEG) and star poly(dimethylsiloxane) (PDMSstar). As anticipated, both the matrix deposition and phenotype of encapsulated osteoblasts varied with scaffold inorganic content, although the directionality of this modulation was contrary to expectation. Specifically, osteoblasts appeared to transdifferentiate into chondrocyte-like cells with increasing scaffold inorganic content, as indicated by increased chondroitin sulfate and collagen type II production and by upregulation of sox9, a transcription factor associated with chondrocytic differentiation. Furthermore, the deposition of bone-like matrix (collagen type I, calcium phosphate, and osteocalcin) decreased with increasing PDMSstar content. The resistance of the PDMSstar-PEG scaffolds to protein adsorption and/or the changes in gel modulus/mesh structure accompanying PDMSstar incorporation may underlie the unexpected increase in chondrocytic phenotype with increasing inorganic content. Combined, the present results indicate that PDMSstar-PEG hybrid gels may prove promising for osteochondral regeneration. © 2010 Wiley Periodicals, Inc. J Biomed Mater Res, 2010
Osteochondral defect repair poses a significant challenge in its reconstruction as the damage is presented in both articular cartilage and the underlying subchondral bone. Tissue engineering approaches have utilized various scaffolds in combination of stem cells and growth factors to regenerate the defect. Still significant challenge remains in creating a scaffold structure that supports the proliferation and differentiation of bone marrow stromal cells (BMSCs) into chondrocytes and osteoblasts while providing the appropriate mechanical stability. Present manuscript reports the fabrication and characterization of a biphasic scaffold system derived from biodegradable polymers such as poly(lactic acid-glycolic acid) (PLGA) as a hard shell and polycaprolactone (PCL) a soft component. Collectively this biphasic scaffold was able to withstand physiological load up to 10,000 cycles in a cyclic compressive testing. The scaffold surface was decorated with PCL aligned nanofibers contacting chondroitin sulfate and hyaluronic acid and nanofibers were cross-linked via carbodiimide linkages to retain these bioactive molecules over the culture period. The present study aims to show the potential of these bioactive scaffolds for the repair ofosteochondral defects. Scaffolds were characterized by Fourier transform infra-red spectroscopy, optical microscopy and cyclic compressive testing. Primary rat bone marrow stem cells were seeded onto scaffolds and cell proliferation and differentiation was evaluated using RTPCR and immunohistochemistry. RT-PCR indicated that the scaffold was able to stimulate the different regions of osteochondral tissue: collagen type II and aggrecan expression in the cartilage region and BMP-2 in the bone region. Similarly protein secretion with induced alignment was confirmed with immunofluorescence imaging. This novel hybrid scaffold shows promising results in the regeneration of cartilage tissue as well as the underlying subchondral bone.