Characteristics, In Vitro, and In Vivo Degradation Behaviors of Synthetic Biodegradable Polyaxial and Amphiphilic Copolyesters Used for Surgical Sutures
Advances in polymer chemistry have revolutionized modern medicine, particularly relating to the development of enhanced solutions for wound healing. Synthetic absorbable sutures are the most commonly used devices to approximate wound edges temporarily until the tissue has healed sufficiently with normal stresses. Many materials in varying formats (e.g. monofilaments, braided multifilament with coatings) have been developed with select properties and designs that are application specific. However, these materials have limitations and on-going advances in polymer chemistry and associated technologies make it critical for researchers to explore engineering solutions to improve this growing three (3) billion dollar market. According to the U.S. Food and Drug Administration; there are still high numbers of adverse events reported on an annual basis, usually due to failures in break strength or surgical site reaction. Furthermore, there is still a strong clinical need to improve handling characteristics of sutures which include reduction of tissue drag, improvements in knot security, and increase in initial strength and degradation life. Previous research has shown that the degree of crystallinity as well hydrophilic (water uptake) properties can impact both biocompatibility as well as mechanical properties. The present study was designed to assess the effects of polymer design on properties of absorbable sutures. The fiber constructs analyzed were either high in glycolide or Ï-dioxanone composition and were analyzed for structural, mechanical, and chemical properties as well as tissue response at varying time points under in vitro and in vivo conditions. This study indicates that differing molecular architectures vary thermal properties, in vitro degradation behavior, and tissue reactions in vivo. Specifically, polyaxial copolymers exhibit lower molecular weights and are less crystalline then their linear counterparts, have different degradation profiles which change the mechanical properties over time, and result in a slightly thicker, fibrous capsule formation in vivo. Furthermore, the addition of hydrophilic regions to Ï-dioxanone homopolymer results in differences in mechanical properties, more rapid degradation than the homopolymer counterpart, and a thicker, more fibrous capsule tissue in vivo.