Protection of ureteral stents against infections is a significant current challenge raised by increasing the number of stentings and infections, microbial resistance to conventional antibiotics and multi-drugs treatments, side effects for the patients like damage of surrounding tissue and high morbidity. Surface engineered biomaterials and ureteral stents, reducing biofilm formation and encrustation would contribute to mitigation of the problem.

The aim of this review is to present the progress during the last 5 years in the development of surface engineered antimicrobial biomaterials and stents with expectation to raise some new fruitful ideas in this direction. Strategies aimed at preventing, disrupting, or removing adherent microbes and biofilms from biomaterials and ureteral stents are its main subject. Various antibacterial agents, modifications, and coatings as well as preparation, deposition and characterization techniques are among the topics covered. A brief market analysis is also included covering the significance of ureteral stents associated infections and a mode of development of a biofilm.

The review of the progress during the last 5 years shows a continuing interest in surface modification and coating employing three principal anti-biofilm strategies: 1) mechanical detachment; 2) killing microbial cells and 3) creation of low-adhesive surfaces. The known surface engineering solutions report a reduced, to some extent, biofilm formation and encrustation of biomaterials and ureteral stents, but none of them is able to totally stop their development.

Some new trends are observed, such as complementary antimicrobial protection by coating and flow dynamic; biodegradable coatings releasing antimicrobial agent; quasi irremovable surface coatings, delivering drug or antimicrobial agent as well as new carbon and biodegradable materials; bacteriophages and phage cocktails, etc. Almost all of them are under intense in vitro studies; only few of them were studied in vivo animal models and none in humans. Some of the liquid infused coatings, already tested in animal models, seem to be the closest to clinical application but so far no one has been applied to ureteral stents.

This review outlines some future research directions and major challenges in the surface engineered biomaterials and ureteral stents. It gives ideas how, by surface engineering, to approach more closely the “clean” ureteral stent to not allow microbial adhesion and encrustation and thus sharply reduce the ureteral stents associated infections and stent dysfunction.

The most important prerequisite of the non-toxic “clean” surface is to be low adhesive. Its anti-biofilm performance could be improved by including bio-surfactant and/or inhibitor of quorum sensing (QS) and/or inhibitor of the crosslinking of the exopolymeric substances (EPSs). The key to identifying a “universal” surface that would repel/release all microbial cells is maybe hidden in the in-depth understanding of the mechanism of the initial reversible adsorption of the EPSs secreted by microbial cells, since it initiates the whole biological cascade of biofilm development.

通过增加支架和感染的数量，对常规抗生素的微生物耐药性和多种药物治疗，对患者的副作用（如周围组织损伤和高发病率），保护输尿管支架免受感染是当前面临的重大挑战。表面工程生物材料和输尿管支架，减少生物膜的形成和结壳将有助于减轻该问题。

这篇综述的目的是介绍表面工程抗菌生物材料和支架在过去五年中的进展，并期望在此方向上提出一些新的富有成果的想法。旨在预防，破坏或清除生物材料和输尿管支架上附着的微生物和生物膜的策略是其主要主题。涵盖的主题包括各种抗菌剂，修饰剂和涂层以及制备，沉积和表征技术。简短的市场分析还包括输尿管支架相关感染的重要性以及生物膜的发展模式。

对过去五年的进展的回顾表明，人们对使用三种主要的抗生物膜策略的表面改性和涂层表现出了持续的兴趣：1）机械分离；2）杀死微生物细胞，以及3）建立低粘性表面。已知的表面工程解决方案报告说在一定程度上减少了生物膜的形成以及生物材料和输尿管支架的结壳，但是它们都无法完全阻止其发展。

观察到一些新的趋势，例如通过涂层和流动动力学实现互补的抗菌保护。释放抗菌剂的可生物降解涂料；准不可去除的表面涂层，用于输送药物或抗菌剂以及新型碳和可生物降解材料；噬菌体和噬菌体鸡尾酒等。几乎所有的人都在进行深入的体外研究。在体内动物模型中只研究了其中的一部分，而在人类中则没有进行过研究。一些已经在动物模型中测试过的液体注入涂层似乎是最接近临床应用的，但是到目前为止，还没有人被应用于输尿管支架。

这篇综述概述了表面工程生物材料和输尿管支架的一些未来研究方向和主要挑战。它提出了一些想法，即如何通过表面工程更加接近“干净”的输尿管支架，以防止微生物粘附和结壳，从而大幅减少输尿管支架相关的感染和支架功能障碍。

无毒“清洁”表面的最重要前提是低粘合力。通过包含生物表面活性剂和/或群体感应抑制剂（QS）和/或外聚合物质（EPSs）交联抑制剂，可以提高其抗生物膜性能。深入了解微生物细胞分泌的EPS最初可逆吸附的机理可能隐藏了识别将排斥/释放所有微生物细胞的“通用”表面的关键，因为它可以引发微生物的整个生物级联反应。生物膜的发展。