Quantitative Analysis of Molecular Absorption into PDMS Microfluidic Channels
Quantitative Analysis of Molecular Absorption into PDMS Microfluidic Channels
复制标题
DOI：
10.1007/s10439-012-0562-z
复制
发表时间：
2012-09-01
影响因子：
3.8
通讯作者：
ElSayed, Mohamed
中科院分区：
文献类型：
--
作者：
Wang, Jack D.;Douville, Nicholas J.;ElSayed, Mohamed
使用聚（二甲基硅氧烷）（PDMS）聚合物制造的微流体装置通常用于体外细胞培养，用于广泛的细胞测定。这些测定通常涉及培养细胞与药物分子或荧光标记物的孵育，同时监测细胞反应。这些测定的准确性取决于实现溶液中溶质分子的一致且可再现的浓度。然而，疏水性治疗和荧光分子倾向于扩散到微流体装置的PDMS壁中，这降低了它们在溶液中的浓度，并因此影响这些测定的准确性和可靠性。在本文中，我们定量研究了一系列常规用于体外细胞测定的标记物（包括[3 H]-地塞米松、[3 H]-地西泮、[14 C]-甘露醇、[3 H]-苯妥英和罗丹明6 G）的分配系数（log P）与它们在PDMS微流控通道中的吸收之间的关系。我们的研究结果表明，一个给定的溶质到PDMS的吸收取决于其log P值定义的亲水/疏水平衡。具体地，结果表明，log P小于2.47的分子表现出最小吸收（< 10%）进入PDMS通道，而log P大于2.62的分子表现出广泛吸收（> 90%）进入PDMS通道。进一步的研究表明，PDMS通道的TiO 2和玻璃涂层分别将疏水分子的吸收降低了2倍和4.5倍（log P > 2.62）。
Microfluidic devices fabricated using poly(dimethylsiloxane) (PDMS) polymer are routinely used for in vitro cell culture for a wide range of cellular assays. These assays typically involve the incubation of cultured cells with a drug molecule or a fluorescent marker while monitoring a cellular response. The accuracy of these assays depends on achieving a consistent and reproducible concentration of solute molecules in solution. However, hydrophobic therapeutic and fluorescent molecules tend to diffuse into the PDMS walls of the microfluidic devices, which reduce their concentration in solution and consequently affect the accuracy and reliability of these assays. In this paper, we quantitatively investigate the relationship between the partition coefficient (log P) of a series of markers routinely used in in vitro cellular assays including [3H]-dexamethasone, [3H]-diazepam, [14C]-mannitol, [3H]-phenytoin, and rhodamine 6G and their absorption into PDMS microfluidic channels. Our results show that the absorption of a given solute into PDMS depends on the hydrophilic/hydrophobic balance defined by its log P value. Specifically, results demonstrate that molecules with log P less than 2.47 exhibit minimal absorption (< 10%) into PDMS channels whereas molecules with log P larger than 2.62 exhibit extensive absorption (> 90%) into PDMS channels. Further investigations showed that TiO2 and glass coatings of PDMS channels reduced the absorption of hydrophobic molecules (log P > 2.62) by 2- and 4.5-folds, respectively.