Electroadhesion of a Hydrogel Enables Suture-less Repair of an Intestinal Injury in Mice

Introduction: Electroadhesion (EA), i.e., adhesion induced by an electric field, is usually seen between two hydrogels, one cationic and one anionic. Our lab recently discovered that EA can also be induced between cationic hydrogels and anionic tissues using a low DC voltage ( < 10 V) for a short duration ( < 60 s).1 This adhesion persists indefinitely after the field is removed but can be reversed by reapplying the field with reversed polarity. This finding opens new possibilities for surgeons to use EA as a suture-less method for patching organs and vessels. Here, for the first time, we evaluate the use of EA in repairing an intestinal injury in live mice. For this purpose, we have developed a handheld, battery-operated device (Figure 1A) to facilitate the application of EA in a clinical setting.

Materials and

Methods: Cationic hydrogels were evaluated for cytotoxicity using the WST-8 Cell Proliferation Assay. In a murine model, a 3 mm cecal enterotomy was repaired using three different techniques: 8-0 Vicryl sutures, a 1×5 mm gel-patch with EA at 9 V for 30 s, and contact adhesion alone. Control experiments were also performed to exclude effects not resulting from EA, including no injury, gel only without electric field (EF), and EF only without gel. Surgical time, animal weight, and intraabdominal adhesion severity were assessed both initially and on postoperative day 6. Histological analysis of inflammation was conducted on hematoxylin and eosin-stained cecal sections at the end of the study.

Results, Conclusions, and Discussions: Our results reveal that the EA approach is safe, allows for normal healing, and can be beneficial over sutures. Importantly, the gels remained well adhered over the injury site in the cecum after Day 6 – proving that the adhesion induced by EA is very durable. All six mice that underwent EA survived and showed no adverse effects from the electrical procedure; for instance, their weights were comparable to those in the control group on Day 6 (Figure 1B). Surgeries utilizing EA were quicker than those using sutures, with an average time of 17 ± 2 minutes compared to 22 ± 2 minutes (Figure 1C), suggesting improved efficiency of the procedure. Wound healing was also more effective in the EA group, with 80% of wounds closed by Day 6 compared to 60% in the suture group, underscoring EA's potential to enhance the natural wound healing process. Histological analysis showed no significant differences in inflammation severity, indicating that the EA gel does not trigger significant adverse immune reactions. Additionally, abdominal adhesions were significantly lower in the EA group, with a Mazuji-modified score of 2.2 ± 0.8 versus the 3.2 ± 0.5 score for sutures.
To conclude, our initial foray into the use of electroadhesion for surgery has yielded promising results. EA was proved to be safe for use in live animals, and showed comparable and even improved outcomes than traditional sutures at the day 6 time point. Injuries sealed by a gel patch healed in a predictable manner and faster than those sutured, and moreover, the procedure time was significantly lowered by the use of EA. These results suggest that EA may be superior to traditional surgical repair methods.

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