The traditional treatment for adhesions is adhesiolysis, a surgical procedure where these fibrotic connections are severed, although this creates further injuries and leads to more adhesions forming, creating a cycle of recurrence. In recent years, laparoscopic surgeries are on the rise owing to their less intensive nature which could reduce the formation of adhesions. Despite this, a significant portion of patients undergoing laparoscopic surgeries still present adhesion formation. Consequently, surgeons opt to utilize barrier materials that separate the afflicted tissue from its surroundings to prevent adhesions from connecting them. There are three commonly employed FDA-approved barriers: Seprafilm®, Interceed® (film-based barrier materials), and Adept® (solution-based barrier). However, these materials suffer from inconsistent efficacy and handling difficulties, preventing them from effectively being utilized in laparoscopic surgeries. Thus, there remains a need for an effective, flexible and easy-to-handle physical barrier specifically optimized for minimally invasive surgeries.
This work introduces a dual-layer biodegradable polymeric film engineered for laparoscopic surgical applications. The first layer is an anti-adhesion layer, consisting of a durable mechanically stable, hydrophilic surface that prevents adhesions from forming on the film. The second layer ensures robust adherence to wet tissue surfaces, significantly improving usability and clinical outcomes in surgical environments. The anti-adhesion layer is composed of a blend of polymers which includes a hydrophilic polymer to increase its hydrophilicity. The hydrophilicity imbues the film’s surface with a hydration layer that prevents the adsorption of fibrinogenic and angiogenic molecules, preventing the formation of adhesions on the film during initial stages of wound healing. The tissue adherent layer is deposited on to the anti-adhesion layer in the form of a fibrous mat which can conform to the complex geometry of the tissue surface, ensuring robust wet tissue adhesion.
Surface hydrophilicity of the anti-adhesion layer was measured through static contact angle measurements with water as the probe liquid. The inclusion of the hydrophilic polymer drastically decreases the contact angle, confirming that the anti-adhesion layer possesses a hydrophilic surface. Moreover, time-dependent changes in the water contact angle of the anti-adhesion layer showed a consistently hydrophilic surface over a period of 8 days; showing that the surface can consistently maintain its hydrophilicity and prevent biomolecule adsorption throughout the wound healing period. The wet-tissue adherence of the second layer has been investigated via pull-apart adhesion testing on porcine tissue, where the tissue adherent layer was attached to a piece of porcine intestine and pulled apart on a Dynamic Mechanical Analyzer to measure the force during failure. The adhesion strength was confirmed to be significantly higher than the adhesion strength of fibrin glue, implying that the tissue-adherent layer shows robust wet tissue adherence. Additionally, the in vitro degradation of the dual-layer film was assessed by measuring the mass loss in phosphate buffered saline at 37oC to mimic physiological conditions. Analysis of the degradation of the films via mass loss showed that 60% of the polymers were present after two months, demonstrating the ability to function as a robust physical barrier throughout clinically relevant wound healing timelines. For analysis of the film’s in vivo efficacy, a murine cecal ligation model was chosen owing to the model’s severity and consistency in producing peritoneal adhesions. Preliminary assessment of the films in this model showed their capability in significantly decreasing the severity and frequency of peritoneal adhesions when compared to a negative control and a Seprafilm® positive control.