Microfluidics drives technological advancement in point-of-care (POC) bioanalytical diagnostics towards portability, fast response and low cost. In most microfluidic bioanalytical applications, flowing antigen/antibody reacts with immobilized antibody/antigen at a constant flux; it is difficult to reach a compromise to simultaneously realize sufficient time for the antigen–antibody interaction and short time for the entire assay. Here, we present a pump-free microfluidic chip, in which flow is self-initialized by capillary pumping and continued by imbibition of a filter paper. Microfluidic units in teardrop shape ensure that flow passes through the reaction areas at a reduced flux to facilitate the association between antigen and antibody and speeds up after the reaction areas. By spotting different antibodies into the reaction area, four types of biomarkers can be measured simultaneously in one microfluidic chip. Moreover, a small-sized instrument was developed for chemiluminescence detection and signal analysis. The system was validated by testing four biomarkers of colorectal cancer using plasma samples from patients. The assay took about 20 minutes. The limit of detection is 0.89 ng mL⁻¹, 1.72 ng mL⁻¹, 3.62 U mL⁻¹ and 1.05 U mL⁻¹ for the assays of carcinoembryonic antigen, alpha-fetoprotein, carbohydrate antigen 125 and carbohydrate antigen 19-9, respectively. This flux-adaptable and self-contained microfluidic platform is expected to be useful in various POC disease-monitoring applications.

中文翻译：

---

基于流量的无泵微流控自足平台，用于多重癌症生物标志物检测

微流体技术推动了即时医疗点（POC）生物分析诊断技术的发展，朝着便携性，快速响应和低成本的方向发展。在大多数微流体生物分析应用中，流动的抗原/抗体会以固定的流量与固定的抗体/抗原反应。要同时实现足够的时间进行抗原-抗体相互作用和较短的整个检测时间很难达成妥协。在这里，我们介绍了一种无泵微流控芯片，其中的流量通过毛细管泵吸自动初始化，并通过吸收滤纸继续流动。滴状的微流体单元确保流量以减少的通量通过反应区域，以促进抗原和抗体之间的缔合并在反应区域之后加速。通过在反应区中点入不同的抗体，可以在一个微流控芯片中同时测量四种类型的生物标志物。而且，开发了用于化学发光检测和信号分析的小型仪器。该系统通过使用来自患者的血浆样本测试四种结直肠癌的生物标记进行了验证。该测定耗时约20分钟。检测限为0.89 ng mL^-1，1.72纳克毫升^-1，3.62ù毫升^-1和1.05毫升ü ^-1分别癌胚抗原，甲胎蛋白，碳水化合物抗原125和糖类抗原19-9，的测定。该通量自适应且自包含的微流体平台有望在各种POC疾病监测应用中使用。