From biofilms to fibrosis: recent advances in research on the pathological microenvironment linked to ureteral stents and their surface functionalization.

In the realm of urology, ureteral stents serve as common implantable devices. However, their prolonged use is often associated with complications, including biofilm infections, encrustation, chronic inflammation, and ureteral fibrosis, which significantly affect patients' quality of life and reduce clinical efficacy. Growing evidence has shown that the development and progression of these problems are not isolated events but the consequence of an imbalance of the pathological stent microenvironment under the influence of multiple factors. Therefore, precise regulation of the stent microenvironment has attracted much attention in the design of next-generation ureteral stents. In this study, we provide a detailed investigation into the mechanisms that lead to the creation of a pathological state after ureteral stents are installed, with particular emphasis on the interactions and regulatory mechanisms associated with stent-related problems. Recent strategies, for functional surface modification, including anti-encrustation, antibacterial, anti-inflammatory, and antifibrotic methods are reviewed, and the mechanisms of action as well as research progress of various novel coatings and functional materials are discussed. Meanwhile, based on the available clinical research information, we objectively analyze the barriers in the translation of functionalized ureteral stents.