Osteogenic Differentiation of hSF-MSCs on PEKK/TCP

Cell suspension, at a density of 2 × 10⁵ cells/mL, was evenly added onto PEKK/TCP dropwise. Four groups were tested in vitro: (1) PEKK + OS (PEKK seeded with hSF-MSCs in osteogenic media), (2) PEKK + SF (PEKK seeded with hSF-MSCs in standard culture media), (3) TCP + OS (TCP seeded with hSF-MSCs in osteogenic media), and (4) TCP + SF (TCP seeded with hSF-MSCs in standard culture media). After 3 days of culture, the standard culture media in the OS groups was changed into an osteogenic media and renewed twice a week while the SF groups were renewed with standard medium at the same frequency. The cellular ALP activity was detected after 1, 4, 7, 14, and 21 days^{70 (link),71 (link)}. SigmaFast p-nitrophenyl phosphate tablets (Sigma) dissolved in deionized H₂O was used with the cell lysate to detect the ALP level. The absorbance was read in a microplate reader at 405 nm (SpectraMax^® M2). The ALP units were standardized to the cell number.