Department of Biomedical Engineering, University of California, Davis, California 95616, USA.
Biomicrofluidics. 2013 Mar 14;7(2):24105. doi: 10.1063/1.4795423. eCollection 2013.
Cytokines are small proteins secreted by leukocytes in blood in response to infections, thus offering valuable diagnostic information. Given that the same cytokines may be produced by different leukocyte subsets in blood, it is beneficial to connect production of cytokines to specific cell types. In this paper, we describe integration of antibody (Ab) microarrays into a microfluidic device to enable enhanced cytokine detection. The Ab arrays contain spots specific to cell-surface antigens as well as anti-cytokine detection spots. Infusion of blood into a microfluidic device results in the capture of specific leukocytes (CD4 T-cells) and is followed by detection of secreted cytokines on the neighboring Ab spots using sandwich immunoassay. The enhancement of cytokine signal comes from leveraging the concept of reconfigurable microfluidics. A three layer polydimethylsiloxane microfluidic device is fabricated so as to contain six microchambers (1 mm × 1 mm × 30 μm) in the ceiling of the device. Once the T-cell capture is complete, the device is reconfigured by withdrawing liquid from the channel, causing the chambers to collapse onto Ab arrays and enclose cell/anti-cytokine spots within a 30 nl volume. In a set of proof-of-concept experiments, we demonstrate that ∼90% pure CD4 T-cells can be captured inside the device and that signals for three important T-cell secreted cytokines, tissue necrosis factor-alpha, interferon-gamma, and interleukin-2, may be enhanced by 2 to 3 folds through the use of reconfigurable microfluidics.
细胞因子是血液白细胞对感染的反应而分泌的小蛋白，因此提供了有价值的诊断信息。鉴于相同的细胞因子可能由血液中的不同白细胞亚群产生，因此将细胞因子的产生与特定的细胞类型联系起来是有益的。在本文中，我们描述了将抗体（Ab）微阵列集成到微流控设备中以实现增强的细胞因子检测。Ab 阵列包含针对细胞表面抗原的斑点以及抗细胞因子检测斑点。将血液注入微流控设备会导致特定白细胞（CD4 T 细胞）的捕获，然后使用夹心免疫测定法在相邻的 Ab 点上检测分泌的细胞因子。细胞因子信号的增强来自于可重构微流控的概念。制造了三层聚二甲基硅氧烷微流控设备，以便在设备的天花板上包含六个微室（1 mm×1 mm×30 μm）。一旦完成 T 细胞捕获，通过从通道中抽出液体来重新配置设备，使腔室坍塌到 Ab 阵列上，并将细胞/抗细胞因子斑点封闭在 30 nl 体积内。在一组概念验证实验中，我们证明可以在设备内捕获约 90%纯度的 CD4 T 细胞，并且通过使用可重构微流控技术，可以将三种重要的 T 细胞分泌的细胞因子（肿瘤坏死因子-α、干扰素-γ和白细胞介素-2）的信号增强 2 到 3 倍。
