Department of Mechanical Engineering, University of Washington, Seattle, WA 98195, USA.
J R Soc Interface. 2013 Aug 21;10(88):20130566. doi: 10.1098/rsif.2013.0566. Print 2013 Nov 6.
Micrometre- and submicrometre-size functionalized beads are frequently used to capture targets of interest from a biological sample for biological characterizations and disease diagnosis. The main challenge of the microbead-based assay is in the immobilization of probe molecules onto the microbead surfaces. In this paper, we report a versatile droplet microfluidics method to fabricate alginate microspheres while simultaneously immobilizing anti-Mycobacterium tuberculosis complex IgY and anti-Escherichia coli IgG antibodies primarily on the porous alginate carriers for specific binding and binding affinity tests. The binding affinity of antibodies is directly measured by fluorescence intensity of stained target bacteria on the microspheres. We demonstrate that the functionalized alginate microspheres yield specificity comparable with an enzyme-linked immunosorbent assay. The high surface area-to-volume ratio of the functionalized porous alginate microspheres improves the detection limit. By using the droplet microfluidics, we can easily modify the size and shape of alginate microspheres, and increase the concentration of functionalized alginate microspheres to further enhance binding kinetics and enable multiplexing.
微米和亚微米大小的功能化微球常用于从生物样本中捕获感兴趣的目标，用于生物特征分析和疾病诊断。基于微球的检测方法的主要挑战在于将探针分子固定在微球表面上。本文报道了一种通用的液滴微流控方法，用于制备海藻酸钠微球，同时将抗结核分枝杆菌复合体 IgY 和抗大肠杆菌 IgG 抗体主要固定在多孔海藻酸钠载体上，用于特异性结合和结合亲和力测试。抗体的结合亲和力通过微球上染色目标细菌的荧光强度直接测量。我们证明，功能化的海藻酸钠微球产生的特异性可与酶联免疫吸附测定相媲美。功能化多孔海藻酸钠微球的高表面积与体积比提高了检测限。通过使用液滴微流控技术，我们可以轻松地改变海藻酸钠微球的大小和形状，并增加功能化海藻酸钠微球的浓度，以进一步增强结合动力学并实现多重检测。
