Adhesive cryogel particles for bridging confined and irregular tissue defects

Tissue reconstruction often involves both hemostasis and bridging of irregular defects. Current methods struggle with complex anatomical surfaces and confined spaces. While prior research has shown the importance of adhesion in wound closure, gaps remain in developing materials that work across diverse tissue types. Traditional sutures and staples are time-consuming and may not conform to irregular geometries. Some adhesives lack sufficient strength or biocompatibility for clinical use. The need for rapid, versatile, and biocompatible tissue adhesives is well established. However, no single material has yet demonstrated broad applicability across multiple organs and defect types. This gap motivated the development of a new adhesive material that could address these limitations. The study aims to bridge this knowledge gap by introducing a novel cryogel-based adhesive.

This research aimed to develop and test a novel tissue adhesive for irregular and confined tissue defects. The specific problem addressed is the challenge of adhering to arbitrary surface topographies in surgical and trauma settings. The motivation stems from the limitations of current adhesives and suturing techniques in complex anatomical regions. The study focuses on creating a material that can rapidly form strong bonds across diverse tissues. The goal is to produce a versatile adhesive suitable for clinical and battlefield applications. The researchers propose that a cryogel-based formulation could offer both mechanical strength and biocompatibility. The study also seeks to evaluate the adhesive's performance in both in vitro and in vivo models. Ultimately, the purpose is to provide a practical solution for tissue bridging in difficult-to-reach anatomical areas.

The adhesive cryogel particles (ACPs) were synthesized using chitosan, acrylic acid, EDC, and NHS. The adhesion strength was measured using an 180-degree peel test on multiple tissue types. Cytotoxicity was assessed through cell proliferation assays on LO2 and Caco-2 cells. Inflammation and biodegradability were studied in rat subcutaneous models. The ability to bridge irregular defects was tested ex vivo on porcine heart, liver, and kidney tissues. In vivo models of liver rupture in rats and intestinal anastomosis in rabbits were used to evaluate clinical applicability. The study compared ACPs to traditional suture methods. The researchers also examined the degradation timeline and tissue healing post-adhesion.

ACPs demonstrated strong adhesion across multiple tissues, with the highest peel strength on porcine heart tissue (670.9 ± 50.1 J/m²). The adhesion strength was also significant for the intestine (607.6 ± 30.0 J/m²) and liver (473.7 ± 37.0 J/m²). Muscle tissue showed lower but still notable adhesion (186.1 ± 13.3 J/m²). In vitro cytotoxicity tests showed high cell viability for both LO2 (98.8 ± 1.2%) and Caco-2 (98.3 ± 1.6%) cells after three days. In vivo inflammation levels in rat liver repair were comparable to suture closure (P = 0.58). Similarly, rabbit intestinal anastomosis showed no significant difference in inflammation compared to sutures (P = 0.40). ACP-based anastomosis was completed in under 30 seconds, significantly faster than traditional suturing (more than 10 minutes). Tissue healing occurred across the adhesion interface after ACP degradation.

The authors propose that ACPs are a promising solution for bridging irregular tissue defects in clinical settings. The strong adhesion values observed across multiple tissues support their potential for use in complex anatomical regions. The high cell viability in in vitro tests suggests good cytocompatibility. The comparable inflammation levels to suture methods indicate acceptable biocompatibility. The rapid application time of ACPs could reduce surgical duration and improve outcomes in time-sensitive procedures. The ability of ACPs to degrade and allow natural tissue healing is a key advantage. The study supports the use of ACPs in both clinical and battlefield scenarios. Further research is needed to confirm long-term outcomes and optimize application techniques.