Enhancement of Apatite Precipitation on an Alkaline Hydrolyzed Poly (Lactic acid-ε-Caprolactone) Film in Simulated Body Fluid

Biodegradable materials, such as poly (lactic acid) (PLA), have been applied to regenerate bone. However, pure PLA is brittle, so it can be modified by blending epsilon-caprolactone (PCL). These biodegradable materials have no known functional activity. In the present study, a copolymer of PLA/PCL (PLCL) film was fabricated by dissolving the materials in chloroform. Carboxylic acid groups (COOH) of PLCL were chemically introduced onto the PLCL film surface by 0.5N NaOH hydrolysis. Apatite formation was evaluated on an alkaline hydrolyzed PLCL film (PLCL-COOH) after immersion in Hanks' balanced salt solution (HBSS, pH7.4) without organic species. Water adsorption in (PBS) PLCL-COOH phosphate buffered saline was also monitored by comparing PLCL. PLCL-COOH provided a greater degree of apatite precipitation than PLCL after 3 and 7-day immersion. Weight loss was significantly different between PLCL-COOH and PLCL films from 3 days until 124 days of immersion in PBS (p<0.05). The contact angle of the PLCL-COOH surface with respect to double distilled water significantly decreased compared with PLCL (p<0.05). Thus, it was predicted that PLCL-COOH would show a better biological response and be applicable in new types of dental materials in dental treatment.