Development and Validation of a Multiplex Fluorescent Immunochromatographic Strip for Simultaneous Quantification of...

Elevated levels of serum matrix metalloproteinase-9 (MMP-9), lipoprotein-associated phospholipase A2 (LP-PLA₂), and high-sensitivity C-reactive protein (hs-CRP) have been shown to be closely associated with the onset and progression of numerous diseases. In light of this, the present study was designed to establish a multiplex fluorescence immunochromatography (FIC) method for the quantitative measurement of MMP-9, LP-PLA₂, and hs-CRP in serum. The FIC methods using europium (III) (Eu³⁺) fluorescent microspheres for quantifying MMP-9, LP-PLA₂, and hs-CRP were individually optimized and established. Subsequently, the multiplex FIC test strips (FICTS) were assembled and evaluated. The sensitivity of the multiplex FICTS for detecting MMP-9 was 0.24 ng/mL, for LP-PLA₂ it was 0.17 ng/mL, and for hs-CRP it was 0.19 ng/mL. The cross-reactivity with nine potential interferents was consistently low, all below 3.00%. The average recovery rates ranged from 101.62% to 105.55%, with all coefficients of variation being less than 5%. The clinical sensitivity and specificity for all three analytes exceeded 93%. Moreover, a strong Pearson correlation was observed between the results obtained using the multiplex FICTS and those from commercial kits (Pearson r: 0.9246, 0.9009, 0.9697, respectively). The multiplex FICTS that we have designed holds great promise for point-of-care quantitative measurement of MMP-9, LP-PLA₂, and hs-CRP. By enabling rapid and accurate on-site detection of these biomarkers, it provides a convenient and efficient alternative to traditional laboratory-based testing methods. This innovative approach has the potential to revolutionize the screening process for diabetic retinopathy.