Oelke Jochen, Kaindl Thomas, Pasc Andreea, Guttenberg Zeno, Wixforth Achim, Tanaka Motomu
Department of Physics, Technical University Munich, Garching D85748, Germany.
Experimental Physics I, University of Augsburg, Augsburg D86159, Germany.
Materials (Basel). 2013 Feb 22;6(2):669-681. doi: 10.3390/ma6020669.
In this paper we demonstrate the combination of supported membranes and so-called flat microfluidics, which enables one to manipulate liquids on flat chip surfaces via "inverse piezoelectric effect". Here, an alternating external electric field applied to the inter-digital transducers excites a surface acoustic wave on a piezoelectric substrate. Employing lithographic patterning of self-assembled monolayers of alkoxysilanes, we successfully confine a free-standing, hemi-cylindrical channel with the volume of merely 7 µL . The experimentally determined maximum flow velocity scales linearly with the acoustic power, suggesting that our current setup can drive liquids at the speed of up to 7 cm/s (corresponding to a shear rate of 280 s) without applying high pressures using a fluidic pump. After the establishment of the functionalization of fluidic chip surfaces with supported membranes, we deposited asymmetric supported membranes displaying well-defined mannose domains and monitored the dynamic adhesion of HB101 expressing mannose-binding receptors. Despite of the further technical optimization required for the quantitative analysis, the obtained results demonstrate that the combination of supported membranes and flat fluidics opens a large potential to investigate dynamic adhesion of cells on biofunctional membrane surfaces with the minimum amount of samples, without any fluidic pump.
在本文中，我们展示了支撑膜与所谓的平面微流体技术的结合，这使得人们能够通过“逆压电效应”在平面芯片表面上操控液体。在此，施加到叉指换能器上的交变外部电场会在压电基板上激发表面声波。利用烷氧基硅烷自组装单分子层的光刻图案化技术，我们成功地限定了一个独立的半圆柱形通道，其体积仅为7微升。实验测定的最大流速与声功率呈线性比例关系，这表明我们当前的装置无需使用流体泵施加高压就能以高达7厘米/秒的速度驱动液体（对应剪切速率为280秒⁻¹）。在用支撑膜实现流体芯片表面功能化之后，我们沉积了具有明确甘露糖结构域的不对称支撑膜，并监测了表达甘露糖结合受体的HB101的动态黏附情况。尽管定量分析还需要进一步的技术优化，但所获得的结果表明，支撑膜与平面流体技术的结合为使用最少的样品量、无需任何流体泵来研究细胞在生物功能膜表面的动态黏附开辟了巨大潜力。
