Temporal and spatial temperature measurement in insulator-based dielectrophoretic devices.
Temporal and spatial temperature measurement in insulator-based dielectrophoretic devices.
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DOI：
10.1021/ac501083h
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发表时间：
2014-07-01
影响因子：
7.4
通讯作者：
Ros, Alexandra
中科院分区：
文献类型：
--
作者：
Nakano, Asuka;Luo, Jinghui;Ros, Alexandra
绝缘体介电泳法是一种相对较新的分析技术，在分选、分离、纯化、分离和预富集等方面具有很大的应用潜力。然而，基于绝缘体的介电泳法(IDEP)在生物样品中的应用需要对微环境进行时间和空间分辨率的精确控制。IDEP实验期间的温度变化是IDEP中的一个关键方面，因为焦耳加热可能会导致各种有害的影响，阻碍重复性。此外，焦耳加热可以潜在地诱导热流，更重要的是可以降解生物分子和其他生物物种。在这里，我们研究了实验上使用热敏染料罗丹明B(RhB)的IDEP器件中的温度变化，并将测量结果与数值模拟进行了比较。我们在相关的缓冲电导范围内进行了温度测量实验，该范围通常用于外加电势下的IDEP应用。为此，我们采用了通道内测量方法和另一种方法，该方法使用了位于IDEP通道略下方的薄膜。我们发现，在S/厘米的100V~3000V的电压范围内，温度与室温没有明显的偏离，比如在蛋白质离子发射极谱实验中。在电导率为300μS/cm的情况下，如以前在3000V下用于线粒体等电势实验的温度，温度从未超过34°C。这一观察表明，在这些条件下，温度对蛋白质和线粒体等电导率的影响是微乎其微的。然而，在较大的电导率(1毫秒/厘米)下，仅在3000伏施加时，温度上升显著，达到可能发生退化的状态。此外，数值模拟也证实了薄层方法具有较低的温升。因此，我们得出结论，薄膜方法更好地提供了与数值模拟更接近的一致性，而且因为它不依赖于IDEP沟道材料。总体而言，我们的研究对两种直接测温的实验技术进行了深入的比较，这两种技术可以适应未来各种IDEP应用。模拟和实验之间的良好一致性也将使人们能够在实验之前评估IDEP设备的温度变化。
Insulator-based dielectrophoresis is a relatively new analytical technique with a large potential for a number of applications, such as sorting, separation, purification, fractionation, and preconcentration. The application of insulator-based dielectrophoresis (iDEP) for biological samples, however, requires the precise control of the microenvironment with temporal and spatial resolution. Temperature variations during an iDEP experiment are a critical aspect in iDEP since Joule heating could lead to various detrimental effects hampering reproducibility. Additionally, Joule heating can potentially induce thermal flow and more importantly can degrade biomolecules and other biological species. Here, we investigate temperature variations in iDEP devices experimentally employing the thermosensitive dye Rhodamin B (RhB) and compare the measured results with numerical simulations. We performed the temperature measurement experiments at a relevant buffer conductivity range commonly used for iDEP applications under applied electric potentials. To this aim, we employed an in-channel measurement method and an alternative method employing a thin film located slightly below the iDEP channel. We found that the temperature does not deviate significantly from room temperature at 100 μS/cm up to 3000 V applied such as in protein iDEP experiments. At a conductivity of 300 μS/cm, such as previously used for mitochondria iDEP experiments at 3000 V, the temperature never exceeds 34 °C. This observation suggests that temperature effects for iDEP of proteins and mitochondria under these conditions are marginal. However, at larger conductivities (1 mS/cm) and only at 3000 V applied, temperature increases were significant, reaching a regime in which degradation is likely to occur. Moreover, the thin layer method resulted in lower temperature enhancement which was also confirmed with numerical simulations. We thus conclude that the thin film method is preferable providing closer agreement with numerical simulations and further since it does not depend on the iDEP channel material. Overall, our study provides a thorough comparison of two experimental techniques for direct temperature measurement, which can be adapted to a variety of iDEP applications in the future. The good agreement between simulation and experiment will also allow one to assess temperature variations for iDEP devices prior to experiments.
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影响因子：
2.9
作者：
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