A novel strategy for improving amperometric biosensor sensitivity using dual-signal synergistic effect for ultrasensitive detection of matrix metalloproteinase-2
Huiqiang Wang, Zhanfang Ma
Index: 10.1016/j.snb.2018.03.119
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Abstract
A new strategy for effectively improving sensitivity of amperometric biosensor based on dual-signal synergistic effect has been developed. Reduced graphene oxide-Au-poly(methylene blue) (rGO-Au-PMB) as a novel redox species with strong current signal at −0.18 V was synthesized by one-step method and used to fabricate the substrate of the biosensor. Peptide (NH2-Gly-Gly-Lys-Gly-Arg-Val-Gly-Leu-Pro-Gly-Cys-SH) was fixed on the rGO-Au-PMB/glass carbon electrode. Pt nanoparticle-aminoferrocene-bovine serum albumin (PtNP-amFc-BSA) was chemically linked to the immobilized peptide, behaving a strong current signal at 0.2 V. The increase of current signal at −0.18 V and the decrease of current signal at 0.2 V of the biosensor were obtained by matrix metalloproteinase-2 (MMP-2, a target analyte) cleaving the immobilized PtNP-amFc-BSA-peptide. The current signal differences of rGO-Au-PMB (ΔIsubstrate) and PtNP-amFc-BSA (ΔIprobe) before and after incubated with MMP-2 were monitored. The synergistic effect of redox substrate and immunoprobe behaved as a better linear relationship between ΔI (ΔIsubstrate + ΔIprobe) and lgCMMP-2 (ng mL−1), resulting in a significantly improved sensitivity 43.86 μA 