Organ transudation dictates in vivo adhesion to tissues.

Fluids wetting organ surfaces are a major hurdle to secure medical devices onto internal tissues. Here we identify transudation - a fluid flow exiting at organ surfaces - as the root cause. Through in vivo experiments in a pig model, we combined transudation monitoring with adhesion tests using poly (ethylene glycol) films. We show that transudation prevents the creation of adhesive contacts and explains adhesion differences among organs. On highly transuding organs like the liver, reducing transudation by a temporary vascular occlusion induced a remarkable transition from lubricated to adhesive contact. Conversely, on weakly transuding organs like the spleen, strong adhesion was achieved even under normal vascularization. This study reveals a critical transudation rate below which clinically relevant adhesion is achieved even with simple pressure sensitive adhesives. We applied this concept to design temporary adhesive fiducial markers capable of resisting organ manipulation during surgery. These findings reshape our understanding of tissue adhesion testing and inspire new adhesive strategies tailored to clinical needs.