Azizi Morteza, Davaji Benyamin, Nguyen Ann V, Zhang Shiying, Dogan Belgin, Simpson Kenneth W, Abbaspourrad Alireza
Department of Food Science, College of Agricultural and Life Sciences, Cornell University, Stocking Hall, Ithaca, New York 14853, United States.
School of Electrical and Computer Engineering, Cornell University, Philips Hall, Ithaca, New York 8 14853, United States.
ACS Sens. 2021 Apr 23;6(4):1560-1571. doi: 10.1021/acssensors.0c02428. Epub 2021 Apr 14.
Antimicrobial resistance is a growing problem, necessitating rapid antimicrobial susceptibility testing (AST) to enable effective in-clinic diagnostic testing and treatment. Conventional AST using broth microdilution or the Kirby-Bauer disk diffusion are time-consuming (e.g., 24-72 h), labor-intensive, and costly and consume reagents. Here, we propose a novel gradient-based microchamber microfluidic (GM) platform to perform AST assay for a wide range of antibiotic concentrations plus zero (positive control) and maximum (negative control) concentrations all in a single test. Antibiotic lateral diffusion within enriched to depleted ( and zero, respectively) cocurrent flowing fluids, moving alongside a micron-sized main channel, is led to form an antibiotic concentration profile in microchambers, connected to the depleted side of the main channel. We examined the tunability of the GM platform, in terms of producing a wide range of antibiotic concentrations in a gradient mode between two consecutive microchambers with changing either the loading fluids' flow rates or their initial concentrations. We also tested the GM platform for profiling bacteria associated with human Crohn's disease and bovine mastitis. Time to result for performing a complete AST assay was ∼ 3-4 h in the GM platform. Lastly, the GM platform tracked the bacterial growth independent of an antibiotic mechanism of action or bacterial species in a robust and easy-to-implement fashion.
抗菌药物耐药性是一个日益严重的问题，因此需要快速进行抗菌药物敏感性测试（AST），以实现有效的临床诊断测试和治疗。使用肉汤微量稀释法或 Kirby-Bauer 纸片扩散法的传统 AST 耗时（例如 24 - 72 小时）、劳动强度大、成本高且消耗试剂。在此，我们提出一种基于梯度的新型微腔微流控（GM）平台，用于在单次测试中对广泛的抗生素浓度以及零浓度（阳性对照）和最大浓度（阴性对照）进行 AST 检测。在富含到耗尽（分别对应零浓度和最大浓度）的并流流体中，抗生素沿微米级主通道横向扩散，在与主通道耗尽侧相连的微腔中形成抗生素浓度分布。我们通过改变加载流体的流速或其初始浓度，研究了 GM 平台在两个连续微腔之间以梯度模式产生广泛抗生素浓度的可调性。我们还测试了 GM 平台对与人类克罗恩病和牛乳腺炎相关细菌的分析能力。在 GM 平台上完成一次完整 AST 检测的出结果时间约为 3 - 4 小时。最后，GM 平台以强大且易于实施的方式跟踪细菌生长，而与抗生素作用机制或细菌种类无关。
