Oriented homo-epitaxial crystallization of polylactic acid displaying a biomimetic structure and improved blood compatibility.

Abstract

Epitaxial crystallization and solid hot-drawing technology were employed to fabricate oriented homo-epitaxial crystallization of polylactic acid (PLA) with nano-topography to enhance its blood compatibility and mechanical characteristics as blood-contacting medical devices. The process involved solid hot stretching the PLA plates. A PLA nutrient solution was then used to immerse the oriented plates to dissolve some of the PLA solutes, ensuring plate integrity. Consequently, the drawing process exponentially enhanced the modulus and tensile strength of the PLA. Orientation and epitaxial crystallization could substantially enhance blood compatibility of PLA by prolonging clotting time and decreasing hemolysis rate, protein adsorption, and platelet activation. The oriented homo-epitaxial crystallization of PLA exhibited a nano-topography and fibrous structure similar to the intimal layer of a blood vessel, and this biomimetic structure was advantageous in decreasing the activation and/or adhesion of platelets.