Stent implantation is an integral procedure in many surgical procedures; however, it can cause many problems when using drug-eluting stents. For example, biliary stent implantation is intended to prevent obstruction during endoscopic retrograde cholangiopancreatography. Due to the limited diameter of biliary stents, patients requiring long-term stent placement may experience recurrent biliary stent obstruction, therefore endangering the patient's life [1], [2].

A prerequisite for surgical intervention is the management of biliary or intestinal biofluids in the patient's body around the wound, which requires control of bleeding and removal of excess biofluids(e.g., wound exudate, blood, and bile) [3], [4], [5]. In recent years, tremendous advances have been made in biofluid control technologies such as self-sealing needles, drug-eluting stents, and shear-thinning hydrogels [6], [7]. In fact, the biliary tract is often injured by biofluid leakage as shown by patients' postoperative extubation certificates [8], [9], [10]. Therefore, there is an urgent need to develop a novel multifunctional stent to effectively remove excessive biofluids.

Bioinspired interface coatings play a significant role in the interaction between biofluid and vivo tissue [11], [12], [13], [14], [15]. Surface wettability of biliary stents can generally affect the wetting behavior of biofluid around wounds. most conventional coatings can easily get wetted by biofluid thus causes adhesion to wound tissue [16], [17], [18]. In contrast, as the superwettability materials prevent unexpected contacting of external fluid with the wounds, but they cannot effective facilitate biofluid removal [19], [20], [21]. Recently, a number of materials with asymmetric wettability have shown their unique ability to transfer water droplets, such as polyester fabrics with wettability gradients, polyurethane (PU)/polyvinyl acetate composite fiber membranes, and single-sided fluorinated cotton fabric membranes [22], [23], [24], [25], [26], [27]. At the same time, biological fluids are also important components of human organs and tissues and play an important role in various life processes such as repairing tissues, transporting substances and maintaining normal metabolism [28], [29], [30], [31]. In addition, the concentration levels of metal ions in biological fluids can provide important information for the early diagnosis of various pathologies. Therefore, quantitative analysis and specific identification of metal ions are of great importance in medical diagnosis and pathogen detection [32], [33], [34], [35], [36], [37], [38], [39], [40], [41]. Thus, controlling surface wettability may provide an opportunity to design wound dressings with effective biofluid management and metal ion detection capabilities. Here, we self-assembled a metal ion-sensitive hydrogel array on the surface of a biliary stent to construct a self-pumping patch that enables unidirectional permeation of fluids. This penetrating Janus Wetted Scaffold Coating unidirectionally drains excess biofluid from the hydrophobic side to the hydrophilic side, thereby preventing biofluid from soaking the wound. In an infected tissue model, we demonstrated that this self-pumping dressing can move biofluids directionally better than conventional dressings. This integrated system provides new clues for the management of excess biofluids around biliary wounds, allows for the efficient collection of biofluids in situ in vivo, and provides informative feedback on diseases associated with changes in biofluidic metal ions.