Manufacturing and Properties of PLA Absorbable Surgical Suture

Polylactic acid (PLA) is a polymer that has good biocompatibility, good biodegradability and excellent mechanical properties. The modulus of elasticity and the thermoplastic ability of PLA can satisfy the need for the carrier material of the cell to grow in bone tissue engineering, such as in regeneration and repair of bone and cartilage tissue. The PLA multifilament was twisted using different twisting parameters and a rotor-twister to fabricate United States Pharmacopoeia (U.S.P.) size 5-0 and 7-0 surgical sutures. The best tensile strengths were 3.1 and 12.3 N, and the coefficients of variation were 3.70% and 1.75%. The PLA suture was then scoured with 1 wt% sodium hydroxide to eliminate impurities, and the knot-pull strengths decreased to 1.66 and 6.84 N for 7-0 and 5-0 PLA sutures, respectively, but still conforming to the U.S.P. knot-pull strength standard. An in vitro hydrolysis test was performed at 37°C by immersing 5-0 PLA suture in physiological saline (0.9 wt% NaCl aqueous solution); the knot-pull strength decreased by 12% after 28 days.