Reduced thermal damage with electrical conductive hydrogel in radiofrequency (RF)-induced intestinal fusion

Radiofrequency (RF)-induced tissue thermal fusion is an innovative method of tissue anastomosis without the need for sutures or staples. However, this technology is generally challenged by significant tissue thermal damage, which may cause tissue necrosis, severely hindering its clinical application. Here, we reported a feasible approach of using a conductive polyacrylamide-alginate-0.5 M calcium ion (denoted as PAAm-Alg-0.5Ca²⁺) hydrogel during tissue fusion process, aiming to reduce thermal damage to the tissues. Electrothermal simulation results indicated that the PAAm-Alg-0.5Ca²⁺ hydrogel effectively reduced the fusion temperature of about 40°C, and produced less thermal damage to adjacent tissues (14.7%). In addition, the result of ex-vivo tissue fusion experiment demonstrated that the welded tissue reached an optimum temperature of about 100°C, and the fusion site exhibited a favorable morphology without tissue carbonization and structure breakdown. Furthermore, the fused tissue with the application of hydrogel could endure a burst pressure of 14.51 ± 1.27 kPa, which was much higher than the normal human intestinal pressure (0.67-6.67 kPa). The histomorphological examination also indicated a comparatively integrated structure and a high collagen volume fraction of fused tissues. Therefore, the application of PAAm-Alg-0.5Ca²⁺ hydrogel in RF-induced tissue fusion is considered an efficient and secure method of reducing excess thermal damage while maintaining anastomotic strength of tissues.