An integrated electrochemical platform for low-volume biosensing

We present a fully integrated, low-cost electrochemical sensing platform that combines a custom 3D-printed flow cell, a microfluidic pumping module, and a C# GUI for synchronized control, acquisition, and on-board analysis. The system addresses limitations of conventional SPE workflows by automating delivery–measure–rinse sequences and stabilizing flow, enabling reproducible measurements with an effective contact volume of ~15 µL (per-run sample load ~45 µL including upstream volume). Using dsDNA as a model analyte, chronoamperometry under continuous flow yielded a linear calibration across 100–1000 µg/mL (R2 ≈ 0.965). Limited SPE reuse was supported by an electrochemical regeneration step, e.g., the first cycle preserved ~90% of the initial signal with similar peak structure, a second cycle produced reduced but qualitatively usable responses, while further cycles showed substantial attenuation/broadening. Under matched conditions, the platform achieved comparable signal to pipette-based delivery with improved reproducibility, reduced baseline drift, and shorter hands-on time. The GUI integrates instrument control with automated dilution calculators and real-time visualization, minimizing operator variability. These results establish a compact, programmable chassis for low-volume SPE assays with straightforward adaptation to point-of-care and field contexts.