The development of smart biomedical devices as efficient tools in early diagnosis and therapy monitoring has recently witnessed unprecedented growth, becoming an emerging field in biomedical engineering. Sponges for endoluminal vacuum therapy, which are intended for transmitting negative pressure as trigger for tissue regeneration and for draining infections in anastomotic leakages, are massively used implants with very complex geometry and high risk of infection. In this work, commercial polyurethane (PU) sponges have been converted into smart biomedical devices by incorporating an electrochemical sensor to monitor the growth of bacteria. Such innovative approach, which allows to track the tissue healing process avoiding further infection development, has been performed applying a three-step process: 1) activation of PU using low pressure oxygen plasma; 2) incorporation of conducting polymer (CP) nanoparticles (NPs) at the surface of the activated PU by chemical oxidative polymerization; and 3) formation of a homogeneous electroactive coating using the CP NPs obtained in 2), as growth nuclei in an electrochemical polymerization. The functionalized PU sponge is able to monitor the bacteria growth in the surrounding media by detecting the concentration of nicotinamide adenine dinucleotide (NADH) from respiration reactions in the cytosol ( bacteria do not have mitochondria). Conversely, respiration in normal eukaryotic cells takes place in the mitochondria, whose double membrane is not permeable to NADH. The sensing performance of the CP-coated PU sponges (limit of detection: 0.06 mM; sensitivity: 1.21 mA/cm) has been determined in the lab using NADH solutions, while a proof of concept have been conducted using bacteria cultures.

中文翻译：

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用于腔内真空治疗的智能聚氨酯内海绵：集成细菌传感器

智能生物医学设备作为早期诊断和治疗监测的有效工具，其发展近年来出现了前所未有的增长，成为生物医学工程的一个新兴领域。用于腔内真空治疗的海绵旨在传递负压作为组织再生的触发因素，并用于引流吻合口瘘中的感染，是一种广泛使用的植入物，具有非常复杂的几何形状和高感染风险。在这项工作中，通过结合电化学传感器来监测细菌的生长，商业聚氨酯（PU）海绵已被转化为智能生物医学设备。这种创新方法可以跟踪组织愈合过程，避免进一步感染发展，已通过三步过程进行：1）使用低压氧等离子体激活 PU； 2）通过化学氧化聚合将导电聚合物（CP）纳米颗粒（NPs）掺入活化的PU表面； 3)使用2)中获得的CP NP作为电化学聚合中的生长核形成均匀的电活性涂层。功能化PU海绵能够通过检测细胞质中呼吸反应产生的烟酰胺腺嘌呤二核苷酸（NADH）浓度来监测周围介质中的细菌生长（细菌没有线粒体）。相反，正常真核细胞的呼吸作用发生在线粒体中，线粒体的双层膜不能渗透 NADH。 CP 涂层 PU 海绵的传感性能（检测限：0.06 mM；灵敏度：1.21 mA/cm）已在实验室中使用 NADH 溶液确定，同时使用细菌培养物进行了概念验证。