No abstract

An optimized scaffold with adaptable architectural and biochemical properties is a goal for articular cartilage (AC) repair. A mechanically enhanced decellularized AC can be an optimistic ECM-derived scaffold. In this study, reinforced decellularized bovine AC was evaluated as a potential scaffold for cartilage repair applications. Individually dispersed single-wall carbon nanotubes (CNTs) were incorporated into chemically decellularized bovine AC samples. The mechanical and thermodynamic properties as well as the biocompatibility of the samples were evaluated by a compressive test, SEM, AFM, FTIR, TGA, DSC and a resazurin test. The Young's modulus of the CNT-incorporated samples (0.67 ± 0.09 MPa) was significantly higher compared to the decellularized ones (0.43 ± 0.06 MPa) (P = 0.001). A higher cell proliferation in the resazurin reduction test after 7 days in culture with human-adipose-derived stem cells (hADSCs) (P < 0.001) was reconfirmed with SEM. FTIR, TGA and DSC confirmed the higher stability when CNT was incorporated into the decellularized AC samples. Our findings indicate that the incorporation of CNTs can substantially enhance the mechanical properties of decellularized AC while retaining its biocompatibility, hence suggesting CNT-incorporated decellularized AC as potential scaffolds for cartilage tissue engineering applications.

Previous researches have emphasized on suitability of decellularized tissues for regenerative applications. The decellularization of cartilage tissue has always been a challenge as the final product must be balanced in both immunogenic residue and mechanical properties. This study was designed to compare and optimize the efficacy of the most common chemical decellularization treatments on articular cartilage. Freeze/thaw cycles, trypsin, ethylenediaminetetraacetic acid (EDTA), sodium dodecyl sulfate (SDS), and Triton‐X 100 were used at various concentrations and time durations for decellularization of bovine distal femoral joint cartilage samples. Histological staining, scanning electron microscopy, DNA quantification, compressive strength test, and Fourier‐transform infrared spectroscopy were performed for evaluation of the decellularized cartilage samples. Treatment with 0.05% trypsin/EDTA for 1 day followed by 3% SDS for 2 days and 3% Triton X‐100 for another 2 days resulted in significant reduction in DNA content and simultaneous maintenance of mechanical properties. Seeding the human adipose‐derived stem cells onto the decellularized cartilage confirmed its biocompatibility. According to our findings, an optimized physiochemical decellularization method can yield in a nonimmunogenic biomechanically compatible decellularized tissue for cartilage regeneration application.

High rate of bone grafting surgeries emphasizes the need for optimal bone substitutes. Biomaterials mimicking the interconnected porous structure of the original bone with osteoconductive and osteoinductive capabilities have long been considered. Hydroxyapatite (HA), as the main inorganic part of natural bone, has exhibited excellent regenerative properties in bone tissue engineering. This manuscript reviews the HA extraction methods from bovine bone, as one of the principal biosources. Essential points in the extraction process have also been highlighted. Characterization of the produced HA through gold standard methods such as XRD, FTIR, electron microscopies (SEM and TEM), mechanical/thermodynamic tests, and bioactivity analysis has been explained in detail. Finally, future perspectives for development of HA constructs are mentioned.