Dual-mode cross-validating biosensor based on a biomimetic Molecular Burr probe for quantitative autoimmune disease evaluation

Antinuclear antibodies (ANA) serve as important serological biomarkers for autoimmune disease evaluation. However, existing detection methods rely predominantly on qualitative or semi-quantitative readouts that are susceptible to subjective interpretation. Herein, we report a quantitative dual-mode cross-validating biosensor for ANA detection based on a biomimetic Molecular Burr (MoB) probe.

Constructed on an intrinsically fluorescent covalent organic framework (COF) scaffold, the MoB probe features a burr-like multivalent surface for antibody immobilization. Through systematic stepwise optimization, the probe achieved an antibody immobilization efficiency of 94.01%, together with fluorescence and peroxidase-mimicking catalytic activity within a single nanoarchitecture. By integrating intrinsic COF fluorescence and the peroxidase-mimicking activity of COF-supported platinum nanoparticles, the biosensor generated independent fluorescent and colorimetric outputs for mutual cross-validation. Under optimized conditions, the biosensor achieved a detection limit of 271 pg/mL across a linear range of 0.1-2000 ng/mL. Validation using 160 clinical serum samples demonstrated high concordance with a commercial enzyme-linked immunosorbent assay. In a dedicated cohort of patients with autoimmune hepatitis and healthy controls, quantitative ANA was combined with alanine aminotransferase, aspartate aminotransferase, and immunoglobulin G. The resulting model yielded an area under the receiver operating characteristic curve of 0.967.

This work establishes a sensitive, objective, and quantitative platform for ANA detection through complementary optical readouts. The results further support the potential value of quantitative ANA as a component of multiparametric assessment for autoimmune hepatitis.