Ethanolamine boric acid buffer

The o-cresolphthalein complex one (OCPC) method was used to quantify calcium deposition by the MSC in microgels as previously described^{14 (link)}. Briefly, the samples were homogenized in 1X Tris–EDTA buffer and centrifuged at 10,000g for 10 min. The supernatant was collected and mixed with a working solution containing 5% ethanolamine/boric acid buffer (Sigma), 5% o-cresolphthalein (Sigma), and 2% hydroxyquinoline (Sigma) in distilled water. The mixture was incubated at room temperature in the dark for 10 min, and the absorbance was read at 575 nm. CaCl₂ (Sigma) dissolved in water at different concentrations served as standards. Microgels with HA in the formulation were excluded from this assay.

The o-cresolphthalein complex one (OCPC) method was used to quantify calcium deposition by the AD-MSC on microgels as previously described (26 (link)). Briefly, the samples were homogenized through sonication in 1X Tris-HCl buffer and centrifuged at 10,000 g for 10 min. The supernatant was then collected and mixed with a working solution containing 5% ethanolamine/boric acid buffer (Sigma), 5% o-cresolphthalein (Sigma), and 2% hydroxyquinoline (Sigma) in DI water. The mixture was incubated at room temperature in the dark for 10 min, and the absorbance was read at 575 nm. CaCl₂ (Sigma) dissolved in DI water at different concentrations served as standards.