Liu Robin Hui, Lenigk Ralf, Druyor-Sanchez Roberta L, Yang Jianing, Grodzinski Piotr
Microfluidics Laboratory, Motorola Labs, Tempe, Arizona 85284, USA.
Anal Chem. 2003 Apr 15;75(8):1911-7. doi: 10.1021/ac026267t.
Conventional DNA microarray hybridization relies on diffusion of target to surface-bound probes, and thus is a rate-limited process. In this paper, a micromixing technique based on cavitation microstreaming principle that was developed to accelerate hybridization process is explained. Fluidic experiments showed that air bubbles resting on a solid surface and set into vibration by a sound field generated steady circulatory flows, resulting in global convection flows and, thus, rapid mixing. The time to fully mix dyed solutions in a 50-microL chamber using cavitation microstreaming was significantly reduced from hours (a pure diffusion-based mixing) to 6 s. Cavitation microstreaming was implemented to enhance DNA hybridization in both fluorescence-detection-based and electrochemical-detection-based DNA microarray chips. The former showed that cavitation microstreaming results in up to 5-fold hybridization signal enhancement with significantly improved signal uniformity, as compared to the results obtained in conventional diffusion-based biochips for a given time (2 h). Hybridization kinetics study in the electrochemical detection-based chips showed that acoustic microstreaming results in up to 5-fold kinetics acceleration. Acoustic microstreaming has many advantages over most existing techniques used for hybridization enhancement, including a simple apparatus, ease of implementation, low power consumption (approximately 2 mW), and low cost.
传统的DNA微阵列杂交依赖于靶标向表面固定探针的扩散，因此是一个速率受限的过程。本文解释了一种基于空化微流原理开发的用于加速杂交过程的微混合技术。流体实验表明，附着在固体表面的气泡在声场作用下振动，产生稳定的循环流，从而形成整体对流，实现快速混合。使用空化微流在50微升腔室中完全混合染色溶液的时间从数小时（基于纯扩散的混合）显著减少至6秒。空化微流被应用于增强基于荧光检测和基于电化学检测的DNA微阵列芯片中的DNA杂交。前者表明，与在传统基于扩散的生物芯片中给定时间（2小时）获得的结果相比，空化微流使杂交信号增强高达5倍，信号均匀性显著提高。基于电化学检测的芯片中的杂交动力学研究表明，声微流使动力学加速高达5倍。与大多数现有的用于增强杂交的技术相比，声微流具有许多优点，包括装置简单、易于实施、低功耗（约2毫瓦）和低成本。
