MAO-B-triggered reaction for an optical triple-signal assay and AND logic gate application based on PEI-functionalized silver nanoparticles.

A novel analytical method was designed and developed that exhibited ultraviolet-visible (UV-Vis), fluorescence (FL), and resonance Rayleigh scattering (RRS) signals for straightforward and comprehensive determination of monoamine oxidase B (MAO-B) using polyethylenimine-functionalized silver nanoparticles (PEI-Ag NPs). Through a facile one-step experiment, and NaOH assisted, in an aqueous solution of 100 ℃ for 40 min PEI reacted with AgNO3 to generate PEI-Ag NPs with a yellow color and weak blue fluorescence. Interestingly, phenylacetaldehyde (PAA), a specific product of MAO-B, causes significant enhancement of the three optical signals of UV-Vis, FL, and RRS. A triple-signal readout sensing system was designed and constructed for MAO-B concentration assay. The limit of detection (LOD) was 0.42 (UV-Vis), 3.49 (FL), and 1.97 (RRS) μg/mL. AND logic gate analysis was applied to enhance its accurate identification. Eventually, the feasibility of the method was assessed by measuring MAO-B amount in human serum samples with satisfying recoveries. The method provided a new concept for the clinical detection of MAO-B.