A study published in Sensors and Actuators: B. Chemical by researchers from the Changchun Institute of Optics, Fine Mechanics and Physics, Chinese Academy of Sciences, introduced a highly integrated centrifugal microfluidics platform for automated chemiluminescence detection of prostate cancer biomarkers. The chip completed the assay in under 20 minutes, demonstrating high sensitivity and minimal manual intervention, which holds promise for point-of-care diagnostic applications.

Traditional chemiluminescence immunoassays, the clinical gold standard for many diseases, rely on large, complex instruments that are unsuitable for resource-limited settings. Centrifugal microfluidics, which uses rotational force to manipulate fluids on a disc-shaped chip, offers a compelling alternative for developing compact, automated point-of-care testing (POCT) devices. However, integrating multi-step assays involving sequential reagent release and magnetic bead manipulation onto a single chip has remained challenging, primarily due to difficulties in precise fluid control.

A key hurdle was managing multiple valves that control the timing of reagent release. Using valves that operate on the same triggering principle often leads to interference and unreliable sequencing as their number increases. To overcome this, the research team proposed a novel integration scheme employing passive valves with different triggering mechanisms. They combined capillary valves, a standard hydrophilic siphon valve, and a specialized Euler force-triggered siphon valve on the same chip. This diversity in operating principles allowed for clearer separation of activation conditions, enabling more robust and precise fluid control.

The team designed and fabricated a polymer chip with multiple chambers to store samples and reagents for detecting Total Prostate-Specific Antigen (TPSA) and Free PSA (FPSA), key biomarkers for prostate cancer. They established a spin protocol where specific rotational speeds and accelerations triggered each valve type in a precise sequence. This automation guided the process: sample and reagent loading, mixing and incubation with magnetic beads, washing steps to remove unbound substances, and finally, the chemiluminescence reaction itself. The entire process was completed within 20 minutes.

Experimental results demonstrated the platform's strong performance. The detection limits were 0.1 ng/mL for TPSA and 0.08 ng/mL for FPSA, with good linearity across clinically relevant concentration ranges. The chip showed high specificity for the target antigens compared to non-specific controls. Furthermore, when compared to the conventional manual benchtop method, the chip-based assay exhibited better consistency and repeatability, with recovery rates closer to 100% and lower variability.

This work presents a step towards practical POCT for prostate cancer. By leveraging a smart combination of passive valves, the platform achieves a high degree of automation without external active components, reducing cost and complexity. The chip's design supports parallel testing and potential future integration with reagent pre-storage, paving the way for fully disposable diagnostic cartridges. This technology could be extended to detect other diseases, making automated, lab-quality testing more accessible outside central laboratories.