Thickness dependence of polydopamine thin films on detection sensitivity of surface plasmon-enhanced fluorescence biosensors

Abstract

A bioinspired polydopamine (PDA) coating is a good candidate for the rapid and cheap chemical modification of biosensor surfaces. Herein, we report the effect of PDA thickness on the detection sensitivity of a fluorescence biosensor utilizing surface plasmon-enhanced fluorescence. The thickness of PDA films was tuned by the incubation time of the dopamine solution and varied from 1 to 17 nm. The detection sensitivity was evaluated as the limit of detection (LOD) of a fluorescently labelled target analyte by a model immunoassay. The LOD was determined to be 1.6 pM for the thickest PDA film and was improved to 1.0 pM by reducing the thickness to the range from 1 to 5 nm, corresponding to the incubation time of 10 to 60 min. The experimental results indicate that the PDA coating is suitable for the surface functionalization of biosensors in mass production as it does not require precise control of the incubation time.

Polydopamine–cellulose nanofiber composite for flexible electrode material

“…Inspired by the structure of DOPA, a dopamine coating having the same functional unit as is in the mussel adhesive proteins has been developed, which can selfpolymerize under mild alkaline conditions and generate polydopamine (PDA) coating layer onto almost all types of materials including glass, ceramics, plastics, metals, and semiconductors [36]. PDA coating has been extensively reported in numerous articles for nanofiller and modifier of bulk nanocomposites, a corrosion protection layer, antifouling supporting layer, stem cell growth, biosensors, and wastewater purification [37][38][39][40][41][42]. Modification of CNF by PDA has been of particular interest for many areas, including oxidative polymerization coating, mechanical properties improvement, flame-retardant composites, caffeine removal, organic dyes removal, Cr(VI) ion removal, oil-separation, enhanced scaffolds, drug delivery, photo-degradation performance, and contaminants removal from water [43][44][45][46][47][48][49][50][51][52][53].…”