A novel approach to detect CD4 T-lymphocytes using a microfluidic chip and compact signal processing circuit

Abstract

CD4 T-lymphocytes (CD4 cells) are a type of T lymphocyte that plays an important role in the immune system, helping to fight germs and protect the body from disease. Accurate enumeration of CD4 T cells is crucial for assessing immune health and diagnosing various diseases. This study presents the development and validation of a novel microfluidic biochip system designed for the detection and counting of CD4 T cells using impedance measurements. The proposed system integrated a cell detection chip with a cost-effective signal processing circuit, which included an instrumental amplifier and a highly sensitive lock-in amplifier. The sensing structure, created using advanced microfabrication technology, consists of three microelectrodes and a 50 × 50 μm measurement aperture. The detection principle relied on the impedance imbalance caused by the presence of CD4 T cells in the fluidic flow between adjacent sensing electrodes. The system's performance was validated through extensive experiments, demonstrating high accuracy in detecting and counting CD4 T cells separated from whole blood based on their magnetic properties. The experimental results indicate that the proposed system was simpler, faster, and more cost-effective compared to traditional laser flow cytometry. Furthermore, the system’s portability and ease of use made it highly suitable for point-of-care diagnostics and on-site cell analysis. The utilization of microfabrication technology and impedance measurement not only enhanced efficiency and accuracy but also offered a reliable solution for rapid biological cell detection. Future work will focus on enhancing the throughput and miniaturizing the sensing structure to align with the high standards of conventional flow cytometry while maintaining cost-effectiveness and simplicity. This research lays a solid foundation for the development of advanced lab-on-a-chip technologies for biological cell detection and analysis, promising significant improvements in healthcare diagnostics and monitoring.