Light-operated microfluidic system for the automated separation and analysis of biomarkers from complex biofluids by...

The precise and automatic handling of low-volume biological samples is crucial in analytical chemistry, biosensing, and lab-on-a-chip technologies. However, traditional manual sampling and handling methods have several handicapping limitations, including operator-dependent variability, increased contamination risks, sample loss due to evaporation or improper pipetting, and reduced reproducibility. Manual workflows often require multiple steps, such as cleaning, sample loading, incubation, washing, and biomolecule extraction, which are prone to inconsistencies and demand significant user expertise. In addition, human intervention can lead to cross-contamination artifacts, and errors in timing and fluid volume control, further affecting the reliability of the quantitative analysis.

To overcome these challenges, we present a fully automated microliter-volume fluidic system designed for sequential fluid manipulation, biomolecule capture, and light-controlled release with minimal human interaction. This system integrates an Arduino UNO-based control unit with micro-dispensing pumps, 3-way isolation valves, and a light irradiation source, executing six-step automatic sequence processes: preliminary cleaning, biosample loading, incubation for biomolecule capture on a chemically modified silicon nanopillar (SiNP) chip, post-capture washing, light-mediated biomolecule release, and final specific biomolecule collection. This microcontroller precisely regulates each step, ensuring accuracy and efficiency in fluid handling within a low-volume reservoir channel. Compared to the manual handling process, the automated system significantly enhances reproducibility and handling time, minimizes sample waste, reduces contamination risks, and improves biomolecule recovery efficiency. Furthermore, the integration of light-triggered biomolecule release introduces a novel, selective approach for controlled molecular interactions, broadening its applicability in biochemical assays and pharmaceutical research.

The development of this automated platform marks a substantial advancement in microfluidic analytical systems, facilitating the transition toward miniaturized, high-precision, and scalable biomedical technologies. Moreover, this system is particularly advantageous for bioanalytical applications, including point-of-care diagnostics, high-throughput screening, proteomics analysis, biomolecules separation and pre-concentration, sample pre-treatment and biomolecules depletion, personalized medicine, and environmental monitoring.