Thermometry in dielectrophoresis chips for contact-free cell handling
Thermometry in dielectrophoresis chips for contact-free cell handling
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DOI：
10.1088/0022-3727/40/1/s14
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发表时间：
2007-01-07
影响因子：
3.4
通讯作者：
Schnelle, T.
中科院分区：
文献类型：
--
作者：
Jaeger, M. S.;Mueller, T.;Schnelle, T.
细胞生物学应用、免疫学和干细胞研究方案要求在严格控制单个细胞与其他细胞或合成表面的接触的情况下进行处理。微流控芯片中的介电泳 (DEP) 是一种在生理条件下非接触式研究、分组、清洗、培养和分选细胞的成熟技术：微电极八极笼、由射频电场供电的多功能介电泳元件，可稳定捕获单细胞或细胞聚集体。对于医学应用和细胞培养，必须量化介电泳操作可能产生的副作用，例如膜极化和焦耳热。因此，我们使用欧姆电阻测量、荧光测定、液晶珠、红外热成像和气泡尺寸测温来表征介电泳笼中电场引起的升温。我们比较了这些技术对电压、缓冲液电导率、频率、笼尺寸和电极表面影响的结果。我们得出的结论是，如果使用低电压和电场减小相位模式，则在培养基中热效应可以被忽略。我们的实验结果为估计介电笼细胞的热效应提供了明确的值，并表明通过优化笼几何形状和降低缓冲液电导率可以最大程度地减少焦耳热。结果还可以用于评估和改进对场诱发效应的理论预测。基于当今芯片处理的可能性，DEP 非常适合细胞操作。
Cell biology applications, protocols in immunology and stem cell research, require that individual cells are handled under strict control of their contacts to other cells or synthetic surfaces. Dielectrophoresis (DEP) in microfluidic chips is an established technique to investigate, group, wash, cultivate and sort cells contact-free under physiological conditions: microelectrode octode cages, versatile dielectrophoretic elements energized with radio frequency electric fields, stably trap single cells or cellular aggregates. For medical applications and cell cultivation, possible side effects of the dielectrophoretic manipulation, such as membrane polarization and Joule heating, have to be quantified. Therefore, we characterized the electric field-induced warming in dielectrophoretic cages using ohmic resistance measurements, fluorometry, liquid crystal beads, infra-red thermography and bubble size thermometry. We compare the results of these techniques with respect to the influences of voltage, electric conductivity of buffer, frequency, cage size and electrode surface. We conclude that in the culture medium thermal effects may be neglected if low voltages and an electric field-reducing phase pattern are used. Our experimental results provide explicit values for estimating the thermal effect on dielectrophoretically caged cells and show that Joule heating is best minimized by optimizing the cage geometry and reducing the buffer conductivity. The results may additionally serve to evaluate and improve theoretical predictions on field-induced effects. Based on present-day chip processing possibilities, DEP is well suited for the manipulation of cells.