Fig. 5
From: Roles of MXenes in biomedical applications: recent developments and prospects
a The amperometry i-t curve obtained at the Au-PCB/Ru/MXene-β-HBD-NAD-GA-BSA electrode at an applied potential of −0.35 V vs. Ag/AgCl (3 M NaCl) in PBS pH 7.4 b The corresponding linear calibration plot for the amperometric determination of β-HBA (n = 3)+. Reproduced with permission from Ref. [77], © Springer Nature 2020. c Typical DPV response of the fabricated biosensor device toward multiple detection of serial concentrations of miR-21 and miR-141 in HEPES buffer (pH 7.4). d Corresponding regression plot illustrating the oxidation current peak values of MB and Fc as a function of miR-21 concentrations. e Schematic diagram representing the whole assay procedure for multiplex and concurrent detection of miR-21 and miR-141. f Nyquist plots (Z′ vs.—Z″) obtained for AuNP/Au and AuNP@MXene/Au and the equivalent Randles circuit model; Inset shows the corresponding cyclic voltammograms of AuNP/Au (black) and AuNP@MXene/Au (red); Experiments were performed in PBS (pH 7.4) comprising 5 mM of Fe (CN)6 4−/3− and 0.1 M KCl with CV scan rate of 50 mV/s. g Typical chronocoulometric response of RuHex on AuNP/Au and AuNP@MXene/Au in 20 mM KCL and hexaammineruthenium (iii) chloride (200 μM) + KCl (20 mM); Dash lines show the outward stretching tangents extrapolated to the Y-axis illustrating the intercept values. h DPV curves obtained for Base141/AuNP/Au and Base141/AuNP@MXene/Au after being hybridized with uncleaved Fc-labeled DNA sequences (DSN products of 20 μM and 1 pM miR-141 reaction). i Statistical analysis of the normalized oxidation current peak value of Fc. Reproduced with permission from Ref. [84], © Elsevier 2020.