Development of microfluidic chip for impedance-based detection of liver cancer biomarkers

Abstract

Microfluidic systems allow precise control of fluid flow and facilitate efficient interactions between biomarkers and detection elements, making them ideal for biomedical applications. In this work, the development of a microfluidic chip for impedance-based detection of liver cancer biomarkers is highlighted, showcasing the advantages of microfluidics in enhancing diagnostic sensitivity and specificity. To achieve this, electrochemical impedance spectroscopy (EIS) was utilized to measure and analyze the presence of specific biomarkers indicative of liver cancer. Initially, various molarities of phosphate buffered saline (PBS) were tested to determine the optimal conditions for EIS measurements. PBS was chosen due to its buffering capacity and ionic strength, which are crucial for maintaining the stability of the biological molecules and ensuring reliable impedance measurements. Different molarities were examined to identify the concentration that provides the best sensitivity and reproducibility in EIS analysis. Following this, EIS measurements were conducted for peptides at different concentrations to establish a detection framework. This step was essential to calibrate the system and understand how peptide concentration affects the impedance response. Magnetic beads (MBs) coated with streptavidin were employed to enhance the detection sensitivity. Streptavidin was chosen for its strong and specific binding affinity to biotin, allowing for efficient immobilization of biotinylated peptides on the magnetic beads. EIS measurements were performed on these magnetic beads to understand their impedance characteristics, providing a baseline for comparison. Subsequently, peptides were bound with the magnetic beads within the microfluidic channel, and their bound impedance was measured. The microfluidic setup ensured a controlled environment for the interaction between the magnetic beads and peptides, improving the accuracy of the measurements. The impedance data were represented using Nyquist plots, which facilitated the visualization of the impedance changes due to biomarker binding. An equivalent circuit model was constructed to interpret the EIS data, allowing for the extraction of key parameters such as charge transfer resistance and double-layer capacitance. These parameters are critical for understanding the electrochemical behavior of the system and the binding efficiency of the biomarkers. The results demonstrated that the developed microfluidic chip could reliably detect liver cancer biomarkers with high sensitivity, paving the way for potential applications in early cancer diagnostics and monitoring. This technology offers a promising approach for non-invasive, rapid, and accurate detection of liver cancer biomarkers, contributing to improved patient outcomes through early diagnosis and timely intervention.