Investigation of Mn Doped ZnO Nanoparticles Towards Ascertaining Myocardial Infarction Through an Electrochemical Detection of Myoglobin

Abstract

Mn-doped ZnO nanostructures were synthesized with three different estimated Mn concentration (atoms/cm3) using sol-gel technique. As synthesized nanostructures were analyzed using X-ray diffraction spectroscopy (XRD), Fourier-transform-infrared spectroscopy (FTIR), and field-emission secondary electron microscopy (FE-SEM). XRD pattern reveals of doped ZnO nanostructures reveal a peak related to Zn2Mn3O8 phase along with peaks related to pure ZnO. Average particle size, estimated using Scherer formula, increases with Mn-doping. FE-SEM reveals morphological change from spherical particles (~15-20 nm) to nano-rods then nano-belt like 2 D super lattice structure after doping. Optical band gap obtain from Tauc's plot is 3.82, 2.05, 2.1 and 2.47 eV for pure-ZnO and Mn-doped samples with 13×1017, 20×1017 and 32×1017 Mn atoms/cm3, respectively. Presence of vibration band from 665 to 680 cm-1 in FTIR spectra endorses metal oxide formation. Nanomaterials were screen printed over working electrode of pre-fabricated three terminal electrode. This was used for electrochemical detection of myoglobin (Mb); a biomarker for acute myocardial infarction and were tested for Mb concentrations from 0-15 nM using cyclic voltammetry and electrochemical impedance spectroscopy. Redox current and charge transfer resistance varied linearly with Mb concentration. 7-fold increased sensitivity towards Mb in Mn-doped ZnO sensors is attributed to doping induced stress in nanostructures. Maximum sensitivity of 95μA-cm-2 nM-1 with LOD of 0.35 nM is observed for ZnO with 13 × 1017 Mn atomic/cm3. Response time of ~10 ms is observed. Interference carried out with 7 nM Cytochrome c and 5 mM HSA reveal different oxidation potential and current value for Mb.

Keywords

• Acute myocardial infarction
• biomarker
• electrochemical
• metal oxides nanoparticles
• myoglobin sensor