A Dual-Hue Recognizable Lateral Flow Immunoassay Corresponding to Distinct Sensitivity Ranges for Timely and...

Early cancer screening is pivotal for reducing mortality yet remains constrained by the trade-off between analytical accuracy and operational simplicity. Here, we present a dual-hue recognizable lateral flow immunoassay (DHLFIA) that enables rapid, quantitative, and user-friendly detection of prostate cancer biomarkers. The platform integrates dual-ratiometric fluorescence transitions, establishing two hue recognition pathways (green-to-red and blue-to-red) with distinct sensitivities for the precise quantification of total (t-PSA) and free (f-PSA) prostate-specific antigens. The differentiated color responsiveness of the two ratio system, governed by the inner filter effect, was elucidated both theoretically and experimentally. This dual-hue strategy enables semiquantitative visual discrimination of the clinically significant "gray zone" (t-PSA: 4-10 ng/mL) by the naked eyes, while smartphone-based tonal analysis of the f-PSA/t-PSA ratio (cutoff = 0.16) allows accurate risk stratification within this range. Validated with clinical serum samples, the DHLFIA achieved a diagnostic accuracy of 96.7%, comparable to chemiluminescent assays, yet offered markedly improved speed and ease of operation. By coupling a modular design with dual-ratiometric readout principles, this work establishes a generalizable framework for multiplexed, point-of-care diagnostics of noncommunicable diseases.