Osteoblastic differentiation by nanocalcium sulfate applied to a collagen membrane

Methods: Dihydrate nCS was fabricated from medical grade dihydrate calcium sulfate using a cryo-vacuum method developed in our laboratory. Commercially available bilayer collagen membranes (BG) were coated with a thin layer of nCS paste and allowed to air dry. Following sterilization by glow discharge, samples of each test group (BG, BG+nCS, nCS paste alone) were placed in a 96 well culture plate. Human osteoblastic cells obtained from culture of discarded specimens of alveolar bone from patients after oral surgery (with written permission according to University at Buffalo Human Subjects Guidelines) were added to each test well in addition to control wells with no added material. Cells were incubated for 48 or 72 hrs at 37°C and viability was assessed with a assay that measures mitochondrial activity (MTT). Alkaline phosphatase was measured biochemically as an assessment of osteoblastic cell differentiation. Sample size was 10 per group and statistical analyses were conducted with ANOVA.

Results: Neither the BG or the nCS had any significant effect on the viability of the osteoblastic cells compared to the control cells. Alkaline phosphatase levels were significantly greater (p<0.05) in all test conditions compared to the control with the BG+nCS group displaying the highest level after 48 hours.

Conclusions: The induction of osteoblast differentiation and maintenance of space afforded by the nCS scaffold, combined with the GTR properties of collagen membranes indicates a nCS coated collagen membrane can provide an effective osteoconductive scaffold.