COF hybrid fibrous nano-network aided surface-enhanced Raman scattering assay for epinephrine analysis

Epinephrine is involved in the stress response and cardiovascular regulation, and abnormal levels are connected to various neurological and endocrine disorders. Surface-enhanced Raman scattering (SERS) provides rapid and sensitive analysis, but its performance critically depends on the nanosubstrate design. Herein, we report a dual-modified covalent organic framework (COF) hybrid fibrous nano-network platform (FNCOF@Ag-CA/APBA) for selective capture and SERS detection of epinephrine. The platform was constructed by in situ growth of a COF layer on electrospun PAN nanofibers, followed by deposition of citric acid-coated Ag nanoparticles and grafting of 4-aminophenylboronic acid (4-APBA) as an affinity probe. Citric acid serves as the Raman reporter, and epinephrine capture is quantified by the decrease in its characteristic SERS peak. Under optimized conditions, the platform exhibits good sensitivity (detection limit of 0.5 µmol L^-1), excellent selectivity over melatonin, norepinephrine, and cholesterol, satisfactory reproducibility (RSD = 6.58%), and reusability for at least three cycles. The method is successfully applied to spiked serum samples with recoveries of 96.50-107.25%. This work demonstrates a reliable and practical SERS platform for epinephrine analysis, highlighting the potential of COF-hybrid fibrous nano-networks in advanced biosensing.