Lu Xiaoguang, Chow Joycelyn Jia Ming, Koo Seok Hwee, Jiang Boran, Tan Thean Yen, Yang Dahou, Ai Ye
Pillar of Engineering Product Development, Singapore University of Technology and Design, Singapore 487372, Singapore.
Clinical Trials & Research Unit, Changi General Hospital, Singapore 529889, Singapore.
Lab Chip. 2021 Jun 1;21(11):2163-2177. doi: 10.1039/d1lc00085c.
Purification of bacteria from human blood samples is essential for rapid identification of pathogens by molecular methods, enabling faster and more accurate diagnosis of bloodstream infection than conventional gold standard blood culture methods. The inertial microfluidic method has been broadly studied to isolate biological cells of interest in various biomedical applications due to its label-free and high-throughput advantages. However, because of the bacteria's tininess, which ranges from 0.5 μm to 3 μm, they are challenging to be effectively focused and sorted out in existing inertial microfluidic devices that work well with biological cells larger than 10 μm. Efforts have been made to sort bacterial cells by utilizing extremely small channel dimensions or employing a sheath flow, which thus results in limitations on the throughput and ease of operation. To overcome this challenge, we develop a method that integrates a non-Newtonian fluid with a novel channel design to allow bacteria to be successfully sorted from larger blood cells in a channel dimension of 120 μm × 20 μm without the use of sheath flows. The throughput of this device with four parallel channels is above 400 μL per minute. The real-time polymerase chain reaction (qPCR) analysis indicates that our inertial sorting approach has a nearly 3-fold improvement in pathogen recovery compared with the commonly used lysis-centrifugation method at pathogen abundances as low as 102 cfu mL-1. With the rapid and simple purification and enrichment of bacterial pathogens, the present inertial sorting method exhibits an ability to enhance the fast and accurate molecular diagnosis of bloodstream bacterial infection.
从人体血液样本中纯化细菌对于通过分子方法快速鉴定病原体至关重要，与传统的金标准血培养方法相比，它能够更快、更准确地诊断血流感染。惯性微流控方法因其无标记和高通量的优点，已在各种生物医学应用中被广泛研究用于分离感兴趣的生物细胞。然而，由于细菌体积微小，范围在0.5μm至3μm之间，在现有的适用于大于10μm生物细胞的惯性微流控装置中，有效地聚焦和分选细菌具有挑战性。人们已努力通过利用极小的通道尺寸或采用鞘流来分选细菌细胞，这导致了通量和操作简便性方面的限制。为了克服这一挑战，我们开发了一种方法，该方法将非牛顿流体与新颖的通道设计相结合，使得在不使用鞘流的情况下，能够在120μm×20μm的通道尺寸中成功地从较大的血细胞中分选细菌。这种具有四个平行通道的装置通量高于每分钟400μL。实时聚合酶链反应（qPCR）分析表明，在病原体丰度低至102 cfu mL-1时，我们的惯性分选方法与常用的裂解离心法相比，病原体回收率提高了近3倍。通过快速简单地纯化和富集细菌病原体，目前的惯性分选方法展现出增强血流细菌感染快速准确分子诊断的能力。
