School of Electrical and Computer Engineering, RMIT University, VIC 3001, Australia.
Anal Chem. 2013 Jul 2;85(13):6364-71. doi: 10.1021/ac400741v. Epub 2013 Jun 14.
Nonviable cells are essential biosystems, due to the functionalities they offer and their effects on viable cells. Therefore, the separation and immobilization of nonviable cells separately or in the vicinity of viable cells is of great importance for many fundamentals investigations in cell biology. However, most nonviable cells become less polarizable than the surrounding medium at conductivities above 0.01 S/m. This means that in such a medium, dielectrophoresis, despite its great versatilities for manipulation of cells, cannot be employed for immobilizing nonviable cells. Here, we present a novel approach to change the dielectrophoretic (DEP) response of nonviable yeast cells by treating them with low concentrations of ionic surfactants such as sodium dodecyl sulfate. After this treatment, they exhibit a strong positive DEP response, even at high medium conductivities. The capability of this treatment is demonstrated in two proof-of-concept experiments. First, we show the sorting and immobilization of viable and nonviable yeast cells, along consecutive microelectrode arrays. Second, we demonstrate the immobilization of viable and nonviable cells in the vicinity of each other along the same microelectrode array. The proposed technique allows DEP platforms to be utilized for the immobilization and subsequent postanalysis of both viable and nonviable cells with and without the presence of each other.
由于无活力细胞具有提供功能以及对有活力细胞产生影响的特性，因此将无活力细胞与有活力细胞分开或在其附近进行分离和固定对于细胞生物学的许多基础研究非常重要。然而，大多数无活力细胞在电导率高于 0.01 S/m 时变得比周围介质的极化性差。这意味着，在这种介质中，尽管介电泳（DEP）在细胞操作方面具有很大的多功能性，但不能用于固定无活力细胞。在这里，我们提出了一种新方法，即用低浓度的离子表面活性剂（如十二烷基硫酸钠）处理无活力酵母细胞，从而改变其介电泳（DEP）响应。经过这种处理后，即使在高介质电导率下，它们也表现出强烈的正 DEP 响应。这种处理的能力在两个概念验证实验中得到了证明。首先，我们展示了沿着连续的微电极阵列对有活力和无活力酵母细胞进行分选和固定。其次，我们证明了在同一微电极阵列上有活力和无活力细胞彼此靠近的固定。所提出的技术允许 DEP 平台用于固定有活力和无活力细胞，以及在彼此存在和不存在的情况下进行后续的分析。
