Fluorescence enhancement of strip patterned silver nanoparticle platforms prepared by room-temperature imprinting technique

Two-dimensional detective platform composed of metal nanoparticles has exhibited excellent performance in metal enhanced fluorescence. Here, we report the preparation of strip patterned silver nanoparticle (Ag NP) platforms by room-temperature imprinting and their fluorescence enhancement performance for a near-infrared fluorescent dye of cyanine-5. The poly(acrylic acid)/poly(allylamine hydrochloride) (PAA/PAH) multilayer film was constructed as the underlying film before the deposition of Ag NPs to provide the good compressibility and fluidity for the room-temperature imprinting. Subsequently, Ag NPs were spray-assembled on the underlying film of PAA/PAH. Depending on the sequence between the room-temperature imprinting and the spraying of Ag NPs, the pattern-spraying and the spray-patterning procedures were respectively implemented for fabricating strip patterned Ag NP platforms. The resulting patterned Ag NP platforms both exhibited stronger capabilities in fluorescence enhancement compared to the planar Ag NP platform. The pattern-sprayed Ag NP platform has a convex strip structure composed of Ag NP film and a fluorescence enhancement of 1.39-fold in comparison with the planar Ag NP platform. In contrast, the spray-patterned Ag NP platform possessed a higher improvement of 2.05-fold, relying on a concavo-convex strip structure. This work developed an alternative strategy for improving the fluorescence enhancement of metal NP platforms.