Fast Detection of Biomolecules in Diffusion-Limited Regime Using Micromechanical Pillars
Fast Detection of Biomolecules in Diffusion-Limited Regime Using Micromechanical Pillars
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DOI：
10.1021/nn202224g
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发表时间：
2011-10-01
期刊：
影响因子：
17.1
通讯作者：
Lazzarino, Marco
中科院分区：
文献类型：
--
作者：
Melli, Mauro;Scoles, Giacinto;Lazzarino, Marco
我们已经开发了一种基于垂直定向振荡梁的微机械传感器，其中与通常所做的相反（例如，振荡杠杆），敏感区域位于振荡器的自由端。在这里使用的微柱几何形状中，分析物吸附仅限于微柱的尖端，从而将分析物分子必须扩散以使表面饱和的体积减小到半径比宏观表面上吸附有效的相应线性距离小2个数量级以上的球体。因此，吸收速率比典型的200 × 20平方微米悬臂快3个数量级。柱振荡检测的光杠杆方法的装置，但几何形状是适合与紧凑的集成检测多路复用。我们通过研究由少于106个DNA分子组成的单链DNA自组装单层（SAM）的形成并通过测量其杂交效率来展示我们的技术。我们表明，结合速度是1000倍，比在“宏观”表面上。我们还表明，杂交的SAM的最大密度的DNA是40%或4倍，在文献中报道的值。这些结果表明，以前在文献中报道的较低的值可以归因于不完全饱和的表面，由于在“宏观”表面上使用的吸附速率较慢。
We have developed a micromechanical sensor based on vertically oriented oscillating beams, in which contrary to what is normally done (for example with oscillating cantilevers) the sensitive area is located at the free end of the oscillator. In the micropillar geometry used here, analyte adsorption is confined only to the tip of the micropillar, thus reducing the volume from which the analyte molecules must diffuse to saturate the surface to a sphere of radius more than 2 orders of magnitude smaller than the corresponding linear distance valid for adsorption on a macroscopic surface. Hence the absorption rate is 3 orders of magnitude faster than on a typical 200 x 20 square micrometer cantilever. Pillar oscillations are detected by means of an optical lever method, but the geometry Is suitable for multiplexing with compact integrated detection. We demonstrate our technology by investigating the formation of a single-strand DNA self-assembled monolayer (SAM) consisting of less than 106 DNA molecules and by measuring their hybridization efficiency. We show that the binding rate is 1000 times faster than on a "macroscopic" surface. We also show that the hybridization of a SAM of maximum density DNA is 40% or 4 times the value reported in the literature. These results suggest that the lower values previously reported in the literature can be attributed to incomplete saturation of the surface due to the slower adsorption rate on the "macroscopic" surfaces used.