Microfluidic filtration and extraction of pathogens from food samples by hydrodynamic focusing and inertial lateral migration
Microfluidic filtration and extraction of pathogens from food samples by hydrodynamic focusing and inertial lateral migration
复制标题
DOI：
10.1007/s10544-014-9905-x
复制
发表时间：
2015-02-01
影响因子：
2.8
通讯作者：
Veres, Teodor
中科院分区：
文献类型：
--
作者：
Clime, Liviu;Hoa, Xuyen D.;Veres, Teodor
用芯片实验室（Lab-on-a-chip，简称LAB）设备检测食品或其他生物样品中的致病菌需要在分析之前进行几个样品制备步骤，这通常涉及清洁复杂的样品基质中的大碎片。这一经常被低估的步骤对于防止这些较大颗粒堵塞装置以及在使用离心分离技术浓缩或分离较小目标微生物用于下游分析时保持初始浓度是重要的。在这种情况下，我们开发了一种新的微流体系统，用于无膜清洁生物样品的碎片颗粒相结合的流体动力学聚焦和惯性横向迁移效应。使用与热成型制造技术相容的热塑性弹性体制造微流体装置，从而产生低成本的一次性装置。微流控芯片的设计和泵送协议进行了优化，通过研究扩散损失与耦合的Navier-Stokes和对流扩散理论模型的数值。惯性横向迁移和分离碎片的稳定性进行了评估，通过荧光显微镜测量标记的颗粒作为一个模型系统。通过用原位光学浊度传感器监测微芯片出口来实验性地研究碎片清洁的效率，同时保留目标病原体（即，通过细菌培养技术评估样品流中的单核细胞增多性李斯特菌（李斯特菌）。优化的泵送方案可以从碎牛肉样品中去除高达50%的碎片，而在相对清洁的样品中，保存的微生物的百分比可以占95%。然而，接种的混浊和清洁样品之间的比较（即，有和没有碎牛肉碎片）表明碎片惯性横向迁移和小微生物的流体动力学聚焦之间存在一定程度的干扰。尽管这种干扰可能会导致芯片性能因目标细菌的损失而显著降低，但即使在最浑浊的测试样品中，样品回收率仍有可能达到70%，碎片去除率也超过50%。由于相对简单的设计、惯性迁移效应本身的鲁棒性、高操作流速和利用低成本材料的制造方法，所提出的装置可以对其中感兴趣的颗粒和生物物种的高通量分离的广泛应用产生影响。
Detecting pathogenic bacteria in food or other biological samples with lab-on-a-chip (LOC) devices requires several sample preparation steps prior to analysis which commonly involves cleaning complex sample matrices of large debris. This often underestimated step is important to prevent these larger particles from clogging devices and to preserve initial concentrations when LOC techniques are used to concentrate or isolate smaller target microorganisms for downstream analysis. In this context, we developed a novel microfluidic system for membrane-free cleaning of biological samples from debris particles by combining hydrodynamic focusing and inertial lateral migration effects. The microfluidic device is fabricated using thermoplastic elastomers being compatible with thermoforming fabrication techniques leading to low-cost single-use devices. Microfluidic chip design and pumping protocols are optimized by investigating diffusive losses numerically with coupled Navier-Stokes and convective-diffusion theoretical models. Stability of inertial lateral migration and separation of debris is assessed through fluorescence microscopy measurements with labelled particles serving as a model system. Efficiency of debris cleaning is experimentally investigated by monitoring microchip outlets with in situ optical turbidity sensors, while retention of targeted pathogens (i.e., Listeria monocytogenes) within the sample stream is assessed through bacterial culture techniques. Optimized pumping protocols can remove up to 50 % of debris from ground beef samples while percentage for preserved microorganisms can account for 95 % in relatively clean samples. However, comparison between inoculated turbid and clean samples (i.e., with and without ground beef debris) indicate some degree of interference between debris inertial lateral migration and hydrodynamic focusing of small microorganisms. Although this interference can lead to significant decrease in chip performance through loss of target bacteria, it remains possible to reach 70 % for sample recovery and more than 50% for debris removal even in the most turbid samples tested. Due to the relatively simple design, the robustness of the inertial migration effect itself, the high operational flow rates and fabrication methods that leverage low-cost materials, the proposed device can have an impact on a wide range of applications where high-throughput separation of particles and biological species is of interest.