Ghonge Tanmay, Ganguli Anurup, Valera Enrique, Saadah Mariam, Damhorst Gregory L, Berger Jacob, Pagan Diaz Gelson, Hassan Umer, Chheda Monish, Haidry Zeeshan, Liu Stan, Hwu Carissa, Bashir Rashid
Biomedical Research Center, Carle Foundation Hospital, Urbana, Illinois 61801, USA.
APL Bioeng. 2017 Oct 9;1(1):016103. doi: 10.1063/1.4989380. eCollection 2017 Dec.
Antigen expression is an important biomarker for cell analysis and disease diagnosis. Traditionally, antigen expression is measured using a flow cytometer which, due to its cost and labor intensive sample preparation, is unsuitable to be used at the point-of-care. Therefore, an automatic, miniaturized assay which can measure antigen expression in the patient could aid in making crucial clinical decisions rapidly. Such a device would also expand the use of such an assay in basic research in biology. In this paper, we present a microfluidic device that can be used to measure antigen expression on cells. We demonstrate our approach using biotin-neutravidin as the binding pair using experimental and computational approaches. We flow beads with varying biotin surface densities ( ) through a polydimethylsiloxane channel with cylindrical pillars functionalized with neutravidin. We analyze how shear stress and collision angle, the angle at which the beads collide with the pillars, affect the angular location of beads captured on the pillars. We also find that the fraction of captured beads as a function of distance () in the channel is affected by . Using , we derive the probability of capture per collision with the pillar (). We show that is linearly related to , which is analogous to the expression level of proteins on cell surfaces. Although demonstrated with beads, this assay can next be expanded with cells, thus paving the way for a rapid antigen expression test.
抗原表达是细胞分析和疾病诊断的重要生物标志物。传统上，使用流式细胞仪测量抗原表达，由于其成本高且样本制备需要大量人力，不适合在床旁使用。因此，一种能够在患者体内测量抗原表达的自动化、小型化检测方法有助于快速做出关键的临床决策。这样的设备还将扩大这种检测方法在生物学基础研究中的应用。在本文中，我们展示了一种可用于测量细胞上抗原表达的微流控设备。我们使用生物素-中性抗生物素蛋白作为结合对，通过实验和计算方法展示了我们的方法。我们使具有不同生物素表面密度（）的珠子流过一个带有用中性抗生物素蛋白功能化的圆柱形柱子的聚二甲基硅氧烷通道。我们分析了剪切应力和碰撞角度（珠子与柱子碰撞的角度）如何影响捕获在柱子上的珠子的角位置。我们还发现，通道中捕获珠子的比例作为距离（）的函数受 影响。使用 ，我们推导出每次与柱子碰撞时的捕获概率（）。我们表明 与 呈线性相关，这类似于细胞表面蛋白质的表达水平。尽管是用珠子进行演示的，但该检测方法接下来可以扩展到细胞，从而为快速抗原表达测试铺平道路。
