Lab-on-a-chip device with an integrated surface acoustic wave micromixer for enhanced porous silicon biosensor performance.

Porous silicon (PSi) biosensors offer significant potential for point-of-care diagnostics, yet their analytical performance is constrained by slow analyte diffusion into the porous matrix. To address this issue, we developed a lab-on-a-chip (LOC) device that combines a PSi immunosensor with a surface acoustic wave (SAW)-driven mixer, housed in a 3D-printed microfluidic flow cell. The platform was evaluated for the optical detection of lactoferrin (LF), a protein biomarker relevant to inflammatory bowel disease and chronic pancreatitis. Acoustic streaming generated by the SAW mixer enhanced convective mixing at the microscale and increased mass transfer of the target analyte towards the sensor surface. SAW-driven mixing achieved a 3-fold increase in the signal-to-noise ratio and a 5-fold reduction in the limit of detection compared to unmixed conditions, advancing the analytical range towards clinically significant concentrations.