Investigation of the Mo₂Ti₂C₃Tx MXene in the electrochemical immunosensing of the respiratory syncytial virus (RSV)

MXenes are a growing family of two-dimensional (2D) layered transition metal carbides, nitrides, and/or carbonitrides. Recently, these materials have been used in many sensing and biosensing platforms because of their excellent electrochemical characteristics. In this work, we investigate the applicability of double transition metal (DTM)-based MXenes in the electrochemical immunosensing of the respiratory syncytial virus (RSV). This ubiquitous virus is considered a major pathogen causing acute lower respiratory tract infections in young children and elderly individuals. The immunosensor was constructed by immobilizing the RSV antibody on screen-printed carbon electrodes modified with graphene oxide and the Mo₂Ti₂C₃Tx DTM MXene. The presence of the RSV antigen was detected in a label-free mode using square wave voltammetry. A low limit of detection of 0.015 pg mL⁻¹ and a remarkable selectivity against other bacterial and viral pathogens, including coronavirus, were achieved. We also compared this MXene with the standard Ti₃C₂Tx and confirmed that it has a 1.21-fold higher electrochemically active effective surface area. The applicability of the Mo₂Ti₂C₃Tx MXene-based immunosensor in real serum samples was also investigated, yielding excellent recovery percentages ranging from 95.48 to 98.59%.