Reagentless, Ratiometric Electrochemical DNA Sensors with Improved Robustness and Reproducibility

Abstract

To make the electrochemical DNA sensors (E-sensor) more robust and reproducible, we have now for the first time adapted the techniques of ratiometric analyses to the field of E-sensors. We did this via the simple expedient way of simultaneously using two redox probes: Methylene blue as the reporter of the conformational change, and ferrocene as an internal control. During the conformational transduction, only the distance between the signal probe and the electrode surface undergoes an appreciable change, while the distance between the control probe and the electrode remains relatively constant. This special design has allowed very reliable target recognition, as illustrated in this report using a human T-lymphotropic virus type I gene fragment. The standard deviation between measurements obtained using different electrodes was an order of magnitude less than that obtained using a classic E-sensor, which we prepared as a control. A limit of detection of 25.1 pM was obtained with our new system, with a single mismatch discrimination factor of 2.33 likewise being observed. Additionally, this concept had general applicability, and preliminary data of a “Signal-On” ratiometric E-sensor are also provided. Taken in concert, these results serve to validate the utility of what we believe will emerge as an easily generalized approach to oligonucleotide recognition and sensing.

A new ratiometric electrochemical sensor for sensitive detection of bisphenol A based on poly-β-cyclodextrin/electroreduced graphene modified glassy carbon electrode

“…The detection limit of the proposed sensor is also lower than those obtained by other electrochemical methods reported previously [1,[11][12][13][14][15][16][17][18][19][20][21][22][23] (Table 1). The predominant reasons might be as follows: (1) the good characteristics of the ratiometric electrochemical assay (self-calibration, low detection limit) [43,[60][61]; (2) the synergistic effect of the electro-reduced graphene (high surface area and good electron transfer property) and Pβ-CD (lots of CD units, the excellent enrichment and host-guest recognition properties of CD). thin-film electrode array 44-4400 44 [11] Graphene/GC 80-5000 20 [12] CTAB/GC 600-100000 100 [13] peptide/Au electrode 1-5000 0.7 [14] SWCNT-CD/GC 10.8-18500 1 [15] CS/N-GS/GC 10-1300 5 [16] Gr-SP-Tyr/GC 2-5480 0.72 [17] Laccase-thionine-CB/SPCE 500-50000 200 [18] AuNPs/SGNF/GC 80-250000 35 [19] SWCNTs-COO-Poly-IL/GC 5-30000 1 [20] PGA/MWCNT-NH2/GC 100-10000 20 [21] MWCNTs/CoPc/SF/GC 50-3000 30 [22] Tyr-NiNPs/SPCE 910-48000 7.1 [23] RhB-incubated Similarly, no interference is observed for 1-naphthols, 2-naphthols, 4-aminophenol (5 equiv).…”

Gold nanoparticles-decorated graphene field-effect transistor biosensor for femtomolar MicroRNA detection

“…Gao and co-workers developed a highly sensitive and selective electrochemical biosensor for direct detection of miRNAs in serum by isothermal amplification cycle (Ren et al, 2013). Du et al detected DNA by robust, reproducible and ratiometric electrochemical DNA sensors (Du et al, 2014). Recently, the label-free FET biosensors have attracted much attention because they do not require electrochemical tags, but attain high sensitivity and selectivity (Cai et al, 2014;Dong et al, 2010;Star et al, 2006).…”

Survey of Redox-Active Moieties for Application in Multiplexed Electrochemical Biosensors

“…This allows for improved multiplexing (e.g., refs 13 and 14 ) and for the introduction of error correcting, ratiometric or differential measurement approaches (e.g., refs 15 and 16 ). To date, however, the literature describing these sensors has almost entirely utilized methylene blue, 6 Nile blue, anthraqui-none, or ferrocene as reporters (e.g., refs 6 and 17–21 ).…”