Electrochemical detection of amyloid-β protein by delaminated titanium carbide MXene/multi-walled carbon nanotubes composite with molecularly imprinted polymer

Amyloid beta-protein, a polypeptide, is known as the reason of neuronal death and is widely recognized as a biomarker of Alzheimer's disease. In this study, a simple and rapid electrochemical biosensor based on delaminated titanium carbide MXene (d-Ti3C2TX MXene) and multi-walled carbon nanotubes (MWCNTs) composite including molecularly imprinted polymers (MIPs) was formed for amyloid-beta having 42-amino-acid-peptide (A beta(42)) protein sensing. After d-Ti3C2TX/MWCNTs composite was prepared by mixing the colloidal solution of d-Ti3C2TX MXene with MWCNTs (mass ratio 3:1), some analytic methods such as x-ray diffraction (XRD), x-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM), UV/Vis spectroscopy, atomic force microscopy (AFM), cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) were performed for characterizations of d-Ti3C2TX MXene, MWCNTs and d-Ti3C2TX/MWCNTs composite. Later, A beta(42) imprinted d-Ti3C2TX/MWCNTs/GCE was prepared in a mixture including 100.0 mM pyrrole (monomer) containing 25.0 mM A beta(42) (template) in phosphate buffer (0.1 M, pH 7.5) by CV method for 25 cycles. A beta(42) imprinted electrode showed a linear range of 1.0 fg mL(-1) - 100.0 fg mL(-1) and detection limit (LOD) of 0.3 fg mL(-1) were obtained. A beta(42) imprinted electrode was examined in terms of stability, repeatability, reproducibility and reusability. Finally, A beta(42) imprinted biosensor was applied to plasma samples for A beta(42) analysis.