A dual-fluorescence analytical strategy using nano fiber probe mediated optofluidic dual-laser biosensor for...

A dual-fluorescence analytical strategy using nano fiber probe mediated optofluidic dual-laser biosensor was firstly fabricated for the simultaneous detection of ricin and abrin. The nano fiber probe (NFP) with nanoporous structure was prepared and employed for evanescent wave field generation, targets recognition/separation, and signal transduction. Owing to size confinement effect, NFP' nanopores could effectively exclude toxin-aptamer complexes while remain aptamers within evanescent wave excitation zone. This assay mode enables parallel and sensitive detection of ricin (LOD of 2.32 ng/mL) and abrin (LOD of 2.56 ng/mL) in single operation. The elimination of complex pretreatment steps or supplementary surface modification processes enables the NFP to maintain remarkable reusability and extended durability, significantly broadening its potential implementation spectrum in practical applications. To obtain enhanced detection sensitivity, ricin and abrin aptamer-complementary DNA (cDNA) functionalized nano fiber probe (CFNFP) was prepared. Based on dsDNA hybridization-mediated signal amplification, lower LODs (0.0086 ng/mL for ricin, 0.004 ng/mL for abrin) were obtained. Validation through selectivity tests, anti-interference assessments, and spiked real water sample analysis demonstrate that both methods enable accurate and rapid detection of ricin and abrin. The dual-fluorescence analytical strategy addresses diverse application needs and enables tailored toxin analysis across different scenarios.