Centrifugal Microfluidic Lateral Flow Assay Enables High Sensitivity Interleukin-6 Detection and Ultrafast Readout of Elevated Analyte Levels.

Balancing sensitivity and time to result is always a challenging part of the development of analytical tools and is of particular importance in clinical and point-of-care diagnostics. In this study, a highly sensitive fluorescence interleukin-6 lateral flow assay (LFA) was developed using centrifugal microfluidics. The sample flow rate through the lateral flow membrane is determined by centrifugal force, which can be precisely controlled with a processing device. Using this precise flow control, an ultrafast early readout after 30 s with a sensitivity of 78.3 pg/mL and a quantitative measurement up to 2000 pg/mL was achieved. Afterward, the flow rate was reduced, and thus, the incubation time increased to achieve a maximum sensitivity of 1.2 pg/mL within 13 min of run time. This high-performance LFA is intended to help particularly vulnerable patient groups, such as pregnant women and neonates, where a rapid and highly sensitive diagnosis of inflammatory biomarkers can make a life-saving difference. In addition to medical applications, the presented system can also be used for the analysis of binding kinetics directly on the lateral flow strip. This enables the development of lateral flow assays with the highest possible sensitivity in the shortest time. Therefore, this advancement leads to a new era of point-of-care testing with future prospects for fully automated centrifugal cassettes with enhanced performance.