Full-SAW Microfluidics-Based Lab-on-a-Chip for Biosensing

• Main Authors: Matteo Agostini, Gina Greco, Marco Cecchini
• Format: Article
• Language: English
• Published: IEEE 2019-01-01
• Series: IEEE Access
• Subjects: Biosensors; lab-on-a-chip (LoC); microfluidics; surface acoustic wave (SAW)
• Online Access: https://ieeexplore.ieee.org/document/8723025/

Many approaches to diagnostic testing remain decades old. Well-established biosensing technologies (e.g., enzyme-linked immunosorbent assays and radio-immunoassays) typically cannot fulfill the requirements of portability and ease of use necessary for point-of-care purposes. Several alternatives have been proposed (e.g., quartz-crystal-microbalances, electrochemical sensors, cantilevers, and surface-plasmon-resonance sensors) but often lack high performance or still necessitate bulk ancillary instruments to operate. Here we present a highly sensitive, versatile, and easily integrable microfluidic lab-on-a-chip (LoC) for biosensing, fully based on surface acoustic waves (SAWs). By using ultra-high-frequency resonator-biosensors, we show that it is possible to perform highly sensitive assays in complex media. This all-electrical readout platform is benchmarked with the biotin-streptavidin binding in presence of non-specific binding proteins (serum albumin) at physiological concentration. The benchmark experiments were performed with the idea of mimicking a biological fluid, in which other molecular species at high concentration are present together with the analytes. We demonstrate that this LoC can detect sub-nanomolar concentrations of analytes in complex media. As a comparison with similar acoustic-wave-based systems, this full-SAW platform outperforms the standard commercial gravimetric sensors (i.e., quartz-crystal-microbalances) and the more common Love-SAW biosensors. This full-SAW LoC could be further developed for the detection of biomarkers in biological fluids.