In heterogeneous microfluidic immunosensors, enhanced capture efficiencies of the antigens (Ag) in the carrier fluids by the surface-immobilized antibodies (Ab) facilitate lower detection limits and thus early detection of disease. Capture efficiency depends on the interplay of transport, reaction parameters and the geometry of the system. A detailed analysis on the enhanced capture efficiencies due to secondary flows in heterogeneous immunosensors has not received significant attention and is the theme of the present work. We conducted a systematic study to observe the significance of secondary forces on the capture efficiency, manifested as the average surface concentration (C_s,avg), in serpentine channels of different lengths (l) and radius of curvature (R_c) as a function of the Reynolds number (Re). Experimental observations were validated with numerical simulations. Micro-PIV studies at different planes and sections of the serpentine microchannels were conducted and matched with the simulated velocity profiles. Further investigation of the process and the geometrical parameters was conducted using numerical simulation and the behaviour of C_s,avg as a function of Re and R_c was plotted for different cases. A highlight of the present work are correlations of C_s,avg as a function of the Dean number (De), as well as its constituents (Re and α). The scientific studies of the geometrical and process parameters which affect the analyte capture advance the understanding of the phenomena and the proposed engineering correlations would be useful in the design of more efficient flow-based heterogeneous immunosensors.

在异质微流体免疫传感器中，通过表面固定的抗体（Ab）提高了载液中抗原（Ag）的捕获效率，有助于降低检测限，从而早期发现疾病。捕集效率取决于运输，反应参数和系统几何形状的相互作用。由于异质免疫传感器中的二次流动导致捕获效率提高的详细分析尚未引起人们的广泛关注，这是本工作的主题。我们进行了系统的研究，以观察次生力对捕获效率的重要性，表现为平均表面浓度（C _s，avg），在不同长度（l）和曲率半径（R _c）的蛇形通道中，作为雷诺数（Re）的函数。实验观察得到了数值模拟的验证。在蛇形微通道的不同平面和截面上进行了Micro-PIV研究，并将其与模拟的速度剖面进行了匹配。使用数值模拟对工艺和几何参数进行了进一步研究，并针对不同情况绘制了C _s，avg与Re和R _c的函数关系。当前工作的重点是C _s，avg的相关性作为Dean数（De）及其组成部分（Re和α）的函数。影响分析物捕获的几何和工艺参数的科学研究促进了对现象的理解，并且所提出的工程相关性在设计更有效的基于流量的异质免疫传感器时将很有用。