Effects of dialdehyde starch on calcification of collagen matrix.

Dialdehyde starch (DAS), a polymeric aldehyde derived from naturally occurring polysaccharide, was used as an additive to the collagen (COL) matrix in an effort to improve its physical and biological properties. The effects of DAS on the thermal stability of COL were characterized by differential scanning calorimetry. The conformational changes in COL were characterized by resistance to protease degradation assay, residual amine analysis, and Fourier-transform infrared spectroscopy. To assess biocompatibility enhancement, the calcium content in porcine aortic valve interstitial cells (PAVICs) on exposure to cardiovascular stents coated with DAS-stabilized COL was examined using atomic absorption spectroscopy. Thermal stability of DAS-stabilized COL was affected by DAS in a concentration dependent manner, reaching maximum at the saturation concentration (DAS:COL = 1:120) and decreasing the thermal stability at the concentrations above saturation. In the long-term exposure condition (21 days), stents coated with DAS at the lowest concentration significantly reduced the calcification rate of PAVIC, when compared with bare stent (p = 0.001). DAS appears to be an efficient additive to the COL matrix in improving its physical and biological properties. Further optimization process is needed for the suitable crosslinking conditions of DAS, which subsequently enhances thermal strength and anticalcification activities of COL matrix.