" 华西临床微生物 "
文章解读
Volume 357, 2022, 131422
IF 8.9
Abstract
The current study developed a homogeneous dual fluorescence and two-dimensional visualization method for E. coli through the detection of β-galactosidase (β-Gal) using cadmium telluride quantum dots (CdTe QDs) and N-methylmesoporphyrin IX (NMM) as signal reporters. β-Gal hydrolyzes 4-Aminophenyl β-D-galactopyranoside (PAPG) to form p-aminophenol (PAP) that further reduces Ag+ and Fe3+ to Ag NPs and Fe2+. Ag+/Ag NPs and Fe3+/Fe2+ can then be identified using QDs and NMM, respectively. A visually readable test strip was generated by combining inkjet printing and using QDs as signal readouts. This test strip enabled the detection of E. coli using color and distance. Under optimized conditions, this system could detect E. coli with a limit of detection (LOD) of 0.2 colony-forming units (CFU)/mL using QDs and 0.3 CFU/mL using NMM, respectively. Furthermore, E. coli could be easily identified as low as 10 CFU/mL in the color and distance reading modes. Compared with clinical plate colony counting and mass spectrometry results, this method demonstrated an adequate consistency for the quantification of E. coli in 60 clinical urine samples, including 14 healthy samples, 21 E. coli negative and 25 E. coli positive ones. The distance reading test strip has been successfully applied in clinical urine samples. Quantitative results of positive patients were consistent with clinical data and fluorometer analysis findings. Therefore, our detection system may provide more solutions for point-of-care testing (POCT) analysis of bacteria.
Keywords: Pathogenic bacteria; NMM and QDs; 2D visual and dual fluorescence; Point-of-care testing; Clinical urine samples; Ag+ and Fe3+
· 开发了一种用于大肠埃希菌检测的均相双荧光和二维可视化策略。
· 所开发的简单、快速、经济的视觉传感器具有高灵敏度和选择性。
· 该方法已成功用于60份临床尿液样本中大肠埃希菌的荧光和可视化分析。
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本研究的目的是开发一种简单、快速、灵敏的大肠埃希菌分析策略，以大肠埃希菌特异性酶：β-Gal酶为标志物，构建均相的双荧光和二维可视化分析方法。β-Gal酶催化底物产生还原性物质对氨基苯酚（4-Aminophenol, PAP），Ag+和 Fe3+ 竞争性与PAP发生还原反应生成银纳米粒子（Ag NPs）和Fe2+，提高了反应效率，减少检测时间。之后，使用碲化镉量子点（cadmium telluride quantum dots, CdTe QDs）和N-甲基卟啉二丙酸IX（N-methylmesoporphyrin IX, NMM）作为信号报告器，实现双荧光信号的检测，并进一步降低了方法的检出限（limit of detection，LOD）。同时，鉴于QDs纳米材料优越的光学性能，结合喷墨打印技术，将QDs成功打印在纸上，开发了一种可用于裸眼检测的可视化试纸条。该试纸能实现基于颜色和距离的视觉读数，便携式实现大肠埃希菌的检测。
本研究建立的荧光信号与可视化分析策略可以成功地用于尿路感染患者尿液样本中大肠埃希菌的检出，具有操作简便、检测时间短、不依赖仪器的优势，有望为病原菌的POCT和家庭自测提供新的选择。
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