Comparison of Multi-Dyes Quenching by Single-Walled Carbon Nanotubes Dispersion with Single-Stranded DNA and Double-Stranded DNA

Abstract

A fluorescence quenching phenomenon of a wide range of fluorophores could be observed in the present of single-walled carbon nanotubes (SWCNTs) suspension. In this study, as a consequence of attaching to SWCNT surface, quenching effect of three kinds of dyes, uranine (Ur), acridine orange (AO), and Rhodamin B (RB), were compared and investigated. Then employed SWCNT suspension with single-stranded DNA and double-stranded DNA, three groups of comparison experiment of quenching properties of Ur vs. AO, Ur vs. RB, and AO vs. RB, were carried out respectively. For the process of adding two dyes into SWCNT suspension, “simultaneous adding” was emphasized because the competitive adsorption of two dyes onto the SWCNT surface was admired in order to investigate the quenching performance. Based on fluorescence results and calculated quenching efficiency, it was found that AO adsorbed onto SWCNT-ssDNA surface prior to Ur and RB, while Ur showed stronger quenching-restrain performance over RB. Overall, SWCNT-dsDNA's quenching capability was weaker than SWCNT-ssDNA. The strengthening fluorescence stem from the AO-dsDNA moiety, and the suppressed emission due to AO-SWCNT moiety, existed at the same time. The emission shift of RB in AO/RB and Ur/RB assay maybe generated by the superimposing of light. The competitive adsorption model was established based on Langmuir adsorption equation. The dispersion strategy of fluorophore/dye into SWCNT suspension without sonicate treatment, and the fundamental quenching effect found in this work were necessary for multi-nanosensor applications that could be useful for fluorophores/dyes detection and quantification in aqueous solution.