Department of Anatomy and Medical Imaging, School of Medical Sciences, University of Auckland, Building 502, Floor 5, Room 502-501, 85 Park Road, Grafton, Auckland, 1142, New Zealand.
School of Pharmacy, Faculty of Medical and Health Sciences, University of Auckland, Auckland, New Zealand.
Biomed Microdevices. 2019 Jul 26;21(3):77. doi: 10.1007/s10544-019-0427-4.
Microfluidics-based gradient generators have been used for various biological applications, specifically chemotaxis in cell culture. However, the ability to generate and maintain long term gradients alongside the ability to quickly switch solutions is a challenge of the current microfabricated systems. In this study, a simple flow-driven microfluidic system was developed to achieve long-term stable concentration gradients. Computational modelling was performed to highlight the fluid dynamics as well as to verify the ability of maintaining stable gradients over 7 days. Numerical simulation was analysed to evaluate the static pressure, velocity magnitude and wall shear stress distribution in the chamber. A microdevice fabricated with polydimethylsiloxane (PDMS), using a standard soft lithography technique is presented. It consists of eight parallel microchannels (5 μm × 30 μm × 1,800 μm) linking source and sink chambers; a syringe pump drives fluid through the sink chamber, advection/diffusion from source to sink establishes a gradient. A gradient of a fluorescent dye was generated under the low flow control at 1-10 μl/h of a simple syringe pump equipped with a pulsation damper that was comparable to a pulseless microfluidic pump. Concentration gradients were formed in 1 h and stable from 2 h out to 5 days and consuming less than 1.0 ml of solution. This study focuses on a novel solution to achieve a long-term microfluidic gradient generator using simple engineering techniques of biomedical microdevices.
基于微流控的梯度发生器已被用于各种生物应用，特别是细胞培养中的趋化性。然而，能够产生和维持长期梯度，同时能够快速切换溶液，这是当前微加工系统面临的挑战。在这项研究中，开发了一种简单的流动驱动微流控系统，以实现长期稳定的浓度梯度。进行了计算建模，以突出显示流体动力学，并验证在 7 天内维持稳定梯度的能力。对腔室内的静态压力、速度大小和壁面剪切应力分布进行了数值模拟分析。展示了一种使用标准软光刻技术制造的聚二甲基硅氧烷 (PDMS) 微器件。它由八个平行的微通道（5μm×30μm×1800μm）组成，连接源和汇室；注射器泵通过汇室驱动流体，从源到汇的对流/扩散建立梯度。在配备脉动阻尼器的简单注射器泵以 1-10μl/h 的低流量控制下产生荧光染料的梯度，该脉动阻尼器与无脉冲微流泵相当。浓度梯度在 1 小时内形成，在 2 小时至 5 天内稳定，消耗的溶液少于 1.0ml。本研究专注于使用生物医学微器件的简单工程技术实现长期微流控梯度发生器的新解决方案。
