Department of Chemistry, Virginia Commonwealth University, 1001 West Main Street, Richmond, Virginia 23284, United States.
Department of Forensic Science, Virginia Commonwealth University, 1015 Floyd Avenue, Richmond, Virginia 23284, United States.
ACS Sens. 2022 Jun 24;7(6):1712-1719. doi: 10.1021/acssensors.2c00439. Epub 2022 May 23.
Although there are many techniques to detect pathogenic bacteria, most of them are only suited for diagnostics. We report a urinary catheter-based colorimetric sensor for potential on-body detection of , the most prevalent bacterial species in urinary tract infections associated with the use of urinary catheters. In urine, indole is secreted by and reacts with a nitrosating agent incorporated in a silicone catheter. A red dimeric product, indoxyl red, is generated within silicone rubber to allow for color-based indole sensing with high sensitivity, linearity, and specificity. This reaction is initiated by the nitrosation reaction of indole at its C-3 position via reagents like sodium nitrite or -nitroso--acetyl-penicillamine under aerobic conditions. The generated 3-nitrosoindole undergoes tautomerization, dimerization, and deoximation to form indoxyl red with high absorbance at 537 nm. In contrast to other indole sensors, the presented method can be applied in real catheters to detect indole and in biofluids such as urine. The is because (1) -nitroso--acetyl-penicillamine, the nitrosating agent, can be impregnated into silicone elastomers, (2) indole from urine is extracted into silicone due to its hydrophobicity, and (3) the high acidity and oxygen solubility of silicone facilitates the sensing reaction within the silicone matrix. This silicone-based colorimetric sensor clearly differentiates below and above 10 CFU/mL, which is the threshold concentration of bacteriuria. We expect that early diagnosis of urinary tract infections using the naked eye is possible by functionalizing an exposed section of urinary catheters with the proposed molecular probe.
尽管有许多技术可以检测病原菌，但大多数技术仅适用于诊断。我们报告了一种基于导尿管的比色传感器，用于潜在的体上检测与使用导尿管相关的尿路感染中最常见的细菌物种 。在尿液中，吲哚由 分泌，并与掺入硅胶导尿管中的硝化剂反应。在硅橡胶内生成红色二聚产物吲哚红，允许基于颜色的吲哚感应具有高灵敏度、线性和特异性。该反应通过亚硝酸钠或 -亚硝基 -乙酰青霉胺等试剂在有氧条件下在吲哚的 C-3 位置的硝化反应起始。生成的 3-亚硝基吲哚经历互变异构、二聚化和脱氧以形成具有 537nm 高吸收的吲哚红。与其他吲哚传感器相比，所提出的方法可以应用于实际导尿管中以检测尿液等生物流体中的吲哚和 。这是因为 (1)-亚硝基 -乙酰青霉胺，硝化剂，可以浸渍到硅橡胶弹性体中，(2)由于其疏水性，尿液中的吲哚被提取到硅橡胶中，以及 (3)硅橡胶的高酸度和氧气溶解度有利于在硅橡胶基质内进行感应反应。这种基于硅橡胶的比色传感器可以清楚地区分低于和高于 10 CFU/mL 的 ，这是菌尿的阈值浓度。我们期望通过用所提出的分子探针功能化暴露的导尿管部分，可以实现对尿路感染的肉眼早期诊断。
