抄録
The biodegradable scaffold material systems with the elastic modulus gradient function in the depth direction would enable the control of the promotion and suppression of their hydrolysis by the osteoclastic activation control during the bone regeneration. Here, we hypothesized that the material systems with the elastic modulus gradient function in the depth direction could be developed by welding two kinds of the biodegradable polymers which have the intermediate compatibility. The aim of this paper is to evaluated the depth-direction elastic modulus distribution of the substrate materials prepared by welding the PCL (polycaprolactone) and PLA (poly-lactic acid), and their effect on the osteoclastic metabolic behavior. In order to improve the osteoclastic adhesion on the PLA substrates, we employed the surface modification by the atmospheric pressure plasma treatment. As a result, the atmospheric pressure plasma treatment successfully improved the osteoclastic adhesion. The best input voltage for the osteoclastic adhesion can be considered as 92 [V]. The crystallinity measurements and tensile tests for the neat PCL, neat PLA and PCL/PLA blend substrates indicated that the PCL and PLA would be mixed in the intermediate portion in the depth-direction and be isolated at the surface portion in the PCL/PLA functional gradient substrates. The indentation tests demonstrated that the prepared PCL/PLA functional gradient substrates could have the elastic modulus gradient function in the depth-direction successfully. Finally, the culture of the osteoclasts and the evaluation of their behavior on the prepared PCL/PLA functional gradient substrates were conducted. As a result, the amount of the PLA/PCL substrate dissolved by the osteoclasts increased with the increase of the culture period until the 4th week, and then decreased at the 5th week. This suggests that the elastic modulus gradient in the depth-direction could control the osteoclastic metabolic behavior.
