Surgical suture assembled with polymeric drug-delivery sheet for sustained, local pain relief

Surgical suture is a strand of biocompatible material designed for wound closure, and therefore can be a medical device potentially suitable for local drug delivery to treat pain at the surgical site. However, the preparation methods previously introduced for drug-delivery sutures adversely influenced the mechanical strength of the suture itself - strength that is essential for successful wound closure. Thus, it is not easy to control drug delivery with sutures, and the drug-delivery surgical sutures available for clinical use are now limited to anti-infection roles. Here, we demonstrate a surgical suture enabled to provide controlled delivery of a pain-relief drug and, more importantly, we demonstrate how it can be fabricated to maintain the mechanical strength of the suture itself. For this purpose, we separately prepare a drug-delivery sheet composed of a biocompatible polymer and a pain-relief drug, which is then physically assembled with a type of surgical suture that is already in clinical use. In this way, the drug release profiles can be tailored for the period of therapeutic need by modifying only the drug-loaded polymer sheet without adversely influencing the mechanical strength of the suture. The drug-delivery sutures in this work can effectively relieve the pain at the surgical site in a sustained manner during the period of wound healing, while showing biocompatibility and mechanical properties comparable to those of the original surgical suture in clinical use.