Cartilage tissue engineering strategies seek to repair damaged tissue using approaches that include scaffolds containing components of the native extracellular matrix (ECM). Articular cartilage consists of glycosaminoglycans (GAGs) which are known to sequester growth factors. In order to more closely mimic the native ECM, this study evaluated the chondrogenic differentiation of mesenchymal stem cells (MSCs), a promising cell source for cartilage regeneration, on fibrous scaffolds that contained the GAG‐mimetic cellulose sulfate. The degree of sulfation was evaluated, examining partially sulfated cellulose (pSC) and fully sulfated cellulose (NaCS). Comparisons were made with scaffolds containing native GAGs (chondroitin sulfate A, chondroitin sulfate C and heparin). Transforming growth factor‐beta3 (TGF‐β3) sequestration, as measured by rate of association, was higher for sulfated cellulose‐containing scaffolds as compared to native GAGs. In addition, TGF‐β3 sequestration and retention over time was highest for NaCS‐containing scaffolds. Sulfated cellulose‐containing scaffolds loaded with TGF‐β3 showed enhanced chondrogenesis as indicated by a higher Collagen Type II:I ratio over native GAGs. NaCS‐containing scaffolds loaded with TGF‐β3 had the highest expression of chondrogenic markers and a reduction of hypertrophic markers in dynamic loading conditions, which more closely mimic in vivo conditions. Studies also demonstrated that TGF‐β3 mediated its effect through the Smad2/3 signaling pathway where the specificity of TGF‐β receptor (TGF‐ βRI)‐phosphorylated SMAD2/3 was verified with a receptor inhibitor. Therefore, studies demonstrate that scaffolds containing cellulose sulfate enhance TGF‐β3‐induced MSC chondrogenic differentiation and show promise for promoting cartilage tissue regeneration.
Osteoarthritis (OA) involves the degeneration of articular cartilage and subchondral bone. The capacity of articular cartilage to repair and regenerate is limited. A biodegradable, fibrous scaffold containing zinc oxide (ZnO) was fabricated and evaluated for osteochondral tissue engineering applications. ZnO has shown promise for a variety of biomedical applications but has had limited use in tissue engineering. Composite scaffolds consisted of ZnO nanoparticles embedded in slow degrading, polycaprolactone to allow for dissolution of zinc ions over time. Zinc has well‐known insulin‐mimetic properties and can be beneficial for cartilage and bone regeneration. Fibrous ZnO composite scaffolds, having varying concentrations of 1–10 wt.% ZnO, were fabricated using the electrospinning technique and evaluated for human mesenchymal stem cell (MSC) differentiation along chondrocyte and osteoblast lineages. Slow release of the zinc was observed for all ZnO composite scaffolds. MSC chondrogenic differentiation was promoted on low percentage ZnO composite scaffolds as indicated by the highest collagen type II production and expression of cartilage‐specific genes, while osteogenic differentiation was promoted on high percentage ZnO composite scaffolds as indicated by the highest alkaline phosphatase activity, collagen production, and expression of bone‐specific genes. This study demonstrates the feasibility of ZnO‐containing composites as a potential scaffold for osteochondral tissue engineering.
more » « less- NSF-PAR ID:
- 10120510
- Publisher / Repository:
- Wiley Blackwell (John Wiley & Sons)
- Date Published:
- Journal Name:
- Biotechnology and Bioengineering
- Volume:
- 117
- Issue:
- 1
- ISSN:
- 0006-3592
- Page Range / eLocation ID:
- p. 194-209
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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Abstract Osteoarthritis is a degenerative joint disease that limits mobility of the affected joint due to the degradation of articular cartilage and subchondral bone. The limited regenerative capacity of cartilage presents significant challenges when attempting to repair or reverse the effects of cartilage degradation. Tissue engineered medical products are a promising alternative to treat osteochondral degeneration due to their potential to integrate into the patient's existing tissue. The goal of this study was to create a scaffold that would induce site‐specific osteogenic and chondrogenic differentiation of human adipose‐derived stem cells (hASC) to generate a full osteochondral implant. Scaffolds were fabricated using 3D‐bioplotting of biodegradable polycraprolactone (PCL) with either β‐tricalcium phosphate (TCP) or decellularized bovine cartilage extracellular matrix (dECM) to drive site‐specific hASC osteogenesis and chondrogenesis, respectively. PCL‐dECM scaffolds demonstrated elevated matrix deposition and organization in scaffolds seeded with hASC as well as a reduction in collagen I gene expression. 3D‐bioplotted PCL scaffolds with 20% TCP demonstrated elevated calcium deposition, endogenous alkaline phosphatase activity, and osteopontin gene expression. Osteochondral scaffolds comprised of hASC‐seeded 3D‐bioplotted PCL‐TCP, electrospun PCL, and 3D‐bioplotted PCL‐dECM phases were evaluated and demonstrated site‐specific osteochondral tissue characteristics. This technique holds great promise as cartilage morbidity is minimized since autologous cartilage harvest is not required, tissue rejection is minimized via use of an abundant and accessible source of autologous stem cells, and biofabrication techniques allow for a precise, customizable methodology to rapidly produce the scaffold.
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Abstract Proper cell–material interactions are critical to remain cell function and thus successful tissue regeneration. Many fabrication processes have been developed to create microenvironments to control cell attachment and organization on a three‐dimensional (3D) scaffold. However, these approaches often involve heavy engineering and only the surface layer can be patterned. We found that 3D extrusion based printing at high temperature and pressure will result an aligned effect on the polymer molecules, and this molecular arrangement will further induce the cell alignment and different differentiation capacities. In particular, articular cartilage tissue is known to have zonal collagen fiber and cell orientation to support different functions, where collagen fibers and chondrocytes align parallel, randomly, and perpendicular, respectively, to the surface of the joint. Therefore, cell alignment was evaluated in a cartilage model in this study. We used small angle X‐ray scattering analysis to substantiate the polymer molecule alignment phenomenon. The cellular response was evaluated both
in vitro andin vivo . Seeded mesenchymal stem cells (MSCs) showed different morphology and orientation on scaffolds, as a combined result of polymer molecule alignment and printed scaffold patterns. Gene expression results showed improved superficial zonal chondrogenic marker expression in parallel‐aligned group. The cell alignment was successfully maintained in the animal model after 7 days with distinct MSC morphology between the casted and parallel printed scaffolds. This 3D printing induced polymer and cell alignment will have a significant impact on developing scaffold with controlled cell–material interactions for complex tissue engineering while avoiding complicated surface treatment, and therefore provides new concept for effective tissue repairing in future clinical applications. © 2018 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 106A: 2190‐2199, 2018. -
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Abstract There is a need for the development of effective treatments for focal articular cartilage injuries. We previously developed a multiphasic 3D‐bioplotted osteochondral scaffold design that can drive site‐specific tissue formation when seeded with adipose‐derived stem cells (ASC). The objective of this study was to evaluate this scaffold in a large animal model. Osteochondral defects were generated in the trochlear groove of Yucatan minipigs and repaired with scaffolds that either contained or lacked an electrospun tidemark and were either unseeded or seeded with ASC. Implants were monitored via computed tomography (CT) over the course of 4 months of in vivo implantation and compared to both open lesions and autologous explants. ICRS II evaluation indicated that defects with ASC‐seeded scaffolds had healing that most closely resembled the aulogous explant. Scaffold‐facilitated subchondral bone repair mimicked the structure of native bone tissue, but cartilage matrix staining was not apparent within the scaffold. The open lesions had the highest volumetric infill detected using CT analysis (
p < 0.05), but the repair tissue was largely disorganized. The acellular scaffold without a tidemark had significantly more volumetric filling than either the acellular or ASC seeded groups containing a tidemark (p < 0.05), suggesting that the tidemark limited cell infiltration into the cartilage portion of the scaffold. Overall, scaffold groups repaired the defect more successfully than an open lesion but achieved limited repair in the cartilage region. With further optimization, this approach holds potential to treat focal cartilage lesions in a highly personalized manner using a human patient's own ASC cells. -
Functional repair of osteochondral (OC) tissue remains challenging because the transition from bone to cartilage presents gradients in biochemical and physical properties necessary for joint function. Osteochondral regeneration requires strategies that restore the spatial composition and organization found in the native tissue. Several biomaterial approaches have been developed to guide chondrogenic and osteogenic differentiation of human mesenchymal stem cells (hMSCs). These strategies can be combined with 3D printing, which has emerged as a useful tool to produce tunable, continuous scaffolds functionalized with bioactive cues. However, functionalization often includes one or more post-fabrication processing steps, which can lead to unwanted side effects and often produce biomaterials with homogeneously distributed chemistries. To address these challenges, surface functionalization can be achieved in a single step by solvent-cast 3D printing peptide-functionalized polymers. Peptide-poly(caprolactone) (PCL) conjugates were synthesized bearing hyaluronic acid (HA)-binding (HAbind–PCL) or mineralizing (E3–PCL) peptides, which have been shown to promote hMSC chondrogenesis or osteogenesis, respectively. This 3D printing strategy enables unprecedented control of surface peptide presentation and spatial organization within a continuous construct. Scaffolds presenting both cartilage-promoting and bone-promoting peptides had a synergistic effect that enhanced hMSC chondrogenic and osteogenic differentiation in the absence of differentiation factors compared to scaffolds without peptides or only one peptide. Furthermore, multi-peptide organization significantly influenced hMSC response. Scaffolds presenting HAbind and E3 peptides in discrete opposing zones promoted hMSC osteogenic behavior. In contrast, presenting both peptides homogeneously throughout the scaffolds drove hMSC differentiation towards a mixed population of articular and hypertrophic chondrocytes. These significant results indicated that hMSC behavior was driven by dual-peptide presentation and organization. The downstream potential of this platform is the ability to fabricate biomaterials with spatially controlled biochemical cues to guide functional tissue regeneration without the need for differentiation factors.more » « less
