Fully automated and integrated centrifugal microfluidic device for high-performance prostate-specific antigen immunoassay

This paper introduces an automated sandwich immunoassay on a centrifugal microfluidic disk for the measurement of prostate-specific antigen (PSA). This novel device leverages an innovative microfluidic network that automates essential assay steps, including ligand binding, washing, and substrate reaction, through precise rotational control, thereby eliminating the need for external pumps, active valves, or other auxiliary equipment. Notably, the system incorporates an advanced flow-switching mechanism for controlled transfer of reaction chamber content to the collection chamber, a highly efficient washing system that accurately transfers specific volumes of wash buffer to the reaction chamber, and a sophisticated microfluidic timer for precise timing of substrate release. These fluid control mechanisms not only enhance assay efficiency but also improve accuracy and reliability, representing a significant advancement in point-of-care diagnostics. The disk contains three identical detection units capable of simultaneously performing three PSA immunoassays within 55 min. Comprehensive performance evaluation across a wide PSA concentration range (0-50 ng/mL) demonstrated a linear range (R-2 > 0.999) of 0.1-25 ng/mL, outperforming traditional manual methods. The automated platform achieved a lower limit of detection (LOD) of 0.07 ng/mL and a limit of quantification (LOQ) of 0.1 ng/mL, marking substantial improvements over the manual method (LOD of 0.17 ng/mL and LOQ of 0.23 ng/mL). A comparative analysis with a standard enzyme-linked immunosorbent assay (ELISA) confirmed the reliability of the device in detecting PSA in ten clinical samples. This microfluidic system offers a promising solution for automated immunoassay-based PSA testing, potentially enhancing clinical diagnostic capabilities for early prostate cancer detection.