Kordzadeh-Kermani Vahid, Vahid Maryam, Ashrafizadeh Seyed Nezameddin, Martinez-Chapa Sergio O, Madou Marc J, Madadelahi Masoud
School of Engineering and Sciences, Tecnologico de Monterrey, Monterrey, NL, Mexico.
Research Lab for Advanced Separation Processes, Department of Chemical Engineering, Iran University of Science and Technology, Narmak, Tehran, Iran.
Microsyst Nanoeng. 2025 Apr 7;11(1):61. doi: 10.1038/s41378-025-00896-5.
Centrifugal microfluidic platforms are highly regarded for their potential in multiplexing and automation, as well as their wide range of applications, especially in separating blood plasma and manipulating two-phase flows. However, the need to use stroboscopes or high-speed cameras for monitoring these tasks hinders the extensive use of these platforms in research and commercial settings. In this study, we introduce an innovative and cost-effective strategy for using an array of light-dependent resistors (LDRs) as optical sensors in microfluidic devices, particularly centrifugal platforms. While LDRs are attractive for their potential use as photodetectors, their bulky size frequently restricts their ability to provide high-resolution detection in microfluidic systems. Here, we use specific waveguides to direct light beams from narrow apertures onto the surface of LDRs. We integrated these LDRs into electrified Lab-on-a-Disc (eLOD) devices, with wireless connectivity to smartphones and laptops. This enables many applications, such as droplet/particle counting and velocity measurement, concentration analysis, fluidic interface detection in multiphase flows, real-time monitoring of sample volume on centrifugal platforms, and detection of blood plasma separation as an alternative to costly stroboscope devices, microscopes, and high-speed imaging. We used numerical simulations to evaluate various fluids and scenarios, which include rotation speeds of up to 50 rad/s and a range of droplet sizes. For the testbed, we used the developed eLOD device to analyze red blood cell (RBC) deformability and improve the automated detection of sickle cell anemia by monitoring differences in RBC deformability during centrifugation using the sensors' signals. In addition to sickle cell anemia, this device has the potential to facilitate low-cost automated detection of other medical conditions characterized by altered RBC deformability, such as thalassemia, malaria, and diabetes.
离心微流控平台因其在多重检测和自动化方面的潜力以及广泛的应用范围而备受关注，尤其是在分离血浆和操控两相流方面。然而，需要使用频闪仪或高速相机来监测这些任务，这阻碍了这些平台在研究和商业环境中的广泛应用。在本研究中，我们引入了一种创新且经济高效的策略，即在微流控设备（特别是离心平台）中使用一系列光敏电阻（LDR）作为光学传感器。虽然LDR作为光探测器具有潜在用途，但它们体积较大，常常限制了其在微流控系统中提供高分辨率检测的能力。在这里，我们使用特定的波导将来自窄孔的光束引导到LDR的表面。我们将这些LDR集成到带电的光盘实验室（eLOD）设备中，并与智能手机和笔记本电脑实现无线连接。这实现了许多应用，如液滴/颗粒计数和速度测量、浓度分析、多相流中的流体界面检测、离心平台上样品体积的实时监测以及血浆分离检测，可替代昂贵的频闪仪设备、显微镜和高速成像。我们使用数值模拟来评估各种流体和场景，包括高达50 rad/s的转速和一系列液滴尺寸。对于测试平台，我们使用开发的eLOD设备通过利用传感器信号监测离心过程中红细胞（RBC）变形性的差异来分析红细胞变形性，并改进镰状细胞贫血的自动检测。除了镰状细胞贫血外，该设备还有潜力促进对其他以红细胞变形性改变为特征的医疗状况的低成本自动检测，如地中海贫血、疟疾和糖尿病。
