In vitro and in vivo evaluation of degradability and biocompatibility of poly(p-dioxanone) hemostatic clips for laparoscopic surgery

For the clinical application of biodegradable hemostatic surgical clips in laparoscopic surgery, it is necessary to determine their degradability and biocompatibility. Herein, in vitro and in vivo studies were undertaken to evaluate the degradability and biocompatibility of bioabsorbable clips made of poly(p-dioxanone). Changes in weight loss, pull-off force, differential scanning calorimetry (DSC), and scanning electron microscopy (SEM) of the poly(p-dioxanone) clips were determined after they were degraded in deionized water and phosphate buffer saline for the in vitro experiment and in laparoscopic models of bile duct ligation(BDL) and right gastroepiploic artery ligation(GEAL) using New Zealand white rabbits for the in vivo experiment. Changes in weight loss and pull-off force were greater in the in vivo experiment than the in vitro experiment. DSC showed the greatest variation in the degree of crystallinity of the clips degraded in deionized water. Stark differences in SEM were observed after 4 weeks of degradation both in vitro and in vivo. Furthermore, the cytocompatibility of the clips was considered satisfactory because the L929 cells could adhere to the clips and proliferate adequately in the presence of the clip extract. Biocompatibility was inferred based on the histological analysis of BDL and GEAL, no significant inflammatory responses were observed after 4 weeks of ligation.