Tanvir Fouzia, Yaqub Atif, Tanvir Shazia, Anderson William A
Department of Zoology, Government College University, Lahore, Pakistan; Department of Chemical Engineering, University of Waterloo, Waterloo, ON, Canada.
Department of Zoology, Government College University, Lahore, Pakistan.
Enzyme Microb Technol. 2017 Apr;99:49-56. doi: 10.1016/j.enzmictec.2017.01.006. Epub 2017 Jan 20.
In this study we report a method for the rapid and sensitive estimation of bacterial cell concentration in solution based on a colorimetric enzyme/gold nanoshells conjugate system. The CTAB capped gold nanoshells are electrostatically attracted by both the bacterial surface and the enzyme β-galactosidase. The preferential binding of cationic (CTAB)-functionalized gold nanoshells to the more negative bacterial surfaces leaves active β-galactosidase in solution, providing an enzyme-amplified colorimetric response of the binding event. A progressive increase in the enzyme activity is evidenced by the conversion of the yellow-orange CPRG substrate into the red chromophore chlorophenol red, which can be correlated with increasing bacterial cell numbers. Using this strategy, the quantification of bacteria at concentrations as low as 10 bacteria/mL of solution has been achieved. The present method of bacterial cell load assessment offers a distinct potential advantage over other conventional methods such as plate counting in terms of ease of operation, rapidity, high sensitivity and quantitative detection of bacterial cells.
在本研究中，我们报告了一种基于比色酶/金纳米壳共轭体系快速灵敏地估算溶液中细菌细胞浓度的方法。十六烷基三甲基溴化铵（CTAB）包覆的金纳米壳通过静电作用被细菌表面和β-半乳糖苷酶吸引。阳离子（CTAB）功能化的金纳米壳优先结合到更带负电的细菌表面，使溶液中留下有活性的β-半乳糖苷酶，从而对结合事件产生酶放大的比色响应。黄色橙色的CPRG底物转化为红色发色团氯酚红，证明酶活性逐渐增加，这与细菌细胞数量增加相关。采用该策略，已实现对低至每毫升溶液10个细菌浓度的细菌进行定量。与其他传统方法如平板计数相比，本细菌细胞载量评估方法在操作简便性、快速性、高灵敏度和细菌细胞定量检测方面具有明显的潜在优势。
