Integrated dual-band microwave resonant microfluidic sensor for quantitative, high-sensitive, and label-free...

An integrated dual-band microwave resonant microfluidic sensor is developed for quantitative, selective, and simultaneous detection of mixed biological solutions. The device integrates dual split-ring resonators with a microfluidic sorting chip, enabling label-free and real-time dielectric characterization of multiple analytes within a single platform. By exploiting two distinct resonant modes, the sensor achieves enhanced sensitivity and cross-interference suppression, allowing precise discrimination among biomolecules with different dielectric signatures. The microfluidic module demonstrated an enrichment efficiency of 84.62% for HepG2 cells, which are efficiently guided into the quantification chamber. Experimental results showed detection sensitivities of 9.55 MHz /(10⁵ cell/mL) for HepG2 cells and 27.8 MHz /(10⁵ cell/mL) for white blood cells, with excellent linearity and repeatability. The integrated architecture facilitates rapid sample handling and spatial isolation of mixed solutions, achieving multiplex detection without chemical labeling or external optics. This work establishes a compact, high-sensitivity, and scalable microwave-microfluidic platform, providing a promising route for high-throughput biochemical analysis, clinical diagnostics, and environmental biosensing.