METHODS: Vancomycin at various concentrations was added to JectOS and polymethyl methacrylate (PMMA). Then, the cement was molded into standardized dimensions for in vitro testing. Cylindrical vancomycin-JectOS samples were subjected to compressive strength. The results obtained were compared to PMMA-vancomycin compressive strength data attained from historical controls. The zone of inhibition was carried out using vancomycin-JectOS and vancomycin-PMMA disk on methicillin-resistant strain culture agar.
RESULTS: With the addition of 2.5%, 5%, and 10% vancomycin, the average compressive strengths reduced to 8.01 ± 0.95 MPa (24.6%), 7.52 ± 0.71 MPa (29.2%), and 7.23 ± 1.34 MPa (31.9%). Addition of vancomycin significantly weakened biomechanical properties of JectOS, but there was no significant difference in the compressive strength at increasing concentrations. The average diameters of zone of inhibition for JectOS-vancomycin were 24.7 ± 1.44 (2.5%) mm, 25.9 ± 0.85 mm (5%), and 26.8 ± 1.81 mm (10%), which outperformed PMMA.
CONCLUSION: JectOS has poor mechanical performance but superior elution property. JectOS-vancomycin cement is suitable as a void filler delivering high local concentration of vancomycin. We recommended using it for contained bone defects that do not require mechanical strength.
METHODS: The decellularization was achieved using a developed closed sonication treatment system for 10 hrs, and continued with a washing process for 5 days. For the control, a simple immersion treatment was set as a benchmark to compare the decellularization efficiency. Histological and biochemical assays were conducted to investigate the cell removal and retention of the vital extracellular matrix. Surface ultrastructure of the prepared scaffolds was evaluated using scanning electron microscope at 5,000× magnification viewed from cross and longitudinal sections. In addition, the biomechanical properties were investigated through ball indentation testing to study the stiffness, residual forces and compression characteristics. Statistical significance between the samples was determined with p-value =0.05.
RESULTS: Histological and biochemical assays confirmed the elimination of antigenic cellular components with the retention of the vital extracellular matrix within the sonicated scaffolds. However, there was a significant removal of sulfated glycosaminoglycans. The surface histoarchitecture portrayed the preserved collagen fibril orientation and arrangement. However, there were minor disruptions on the structure, with few empty micropores formed which represented cell lacunae. The biomechanical properties of bioscaffolds showed the retention of viscoelastic behavior of the scaffolds which mimic native tissues. After immersion treatment, those scaffolds had poor results compared to the sonicated scaffolds due to the inefficiency of the treatment.
CONCLUSION: In conclusion, this study reported that the closed sonication treatment system had high capabilities to prepare ideal bioscaffolds with excellent removal of cellular components, and retained extracellular matrix and biomechanical properties.
METHOD: A strain comprising 10% direct compression and 1% compressive shear was applied to bovine chondrocytes seeded in an agarose gel during two 12-hour conditioning periods separated by a 12-hour resting period.
RESULTS: The bi-axial-loaded chondrocytes demonstrated a significant increase in glycosaminoglycan synthesis compared with samples exposed to uni-axial or no loading over the same period (p<0.05). The use of a free-swelling recovery period prior to the loading regime resulted in additional glycosaminoglycan production and a significant increase in DNA content (p<0.05), indicating cell proliferation.
CONCLUSIONS: These results demonstrate that the use of a bi-axial loading regime results in increased matrix production compared with uni-axial loading.