Development of an advanced electrochemical biosensor for choline detection using MXene, MWCNT-AuNPs, and Fe3O4NPs

Choline, as an important neurotransmitter and metabolic substance, plays an important role in human metabolism, information transmission, regulation of apoptosis, and promotion of fat metabolism, etc. Its level changes and metabolic abnormalities can also be used as diagnostic markers for a variety of diseases. In this study, we developed an advanced electrochemical choline biosensor by modifying the electrode surface with MXene, multi-walled carbon nanotubes functionalized with gold nanoparticles (MWCNT-AuNPs), and Fe 3 O 4 nanoparticles (Fe 3 O 4 NPs). MWCNT will be interspersed with MXene to avoid strong interlayer aggregation. At the same time, the composite of AuNPs and MWCNT can avoid the agglomeration of Au and further improve the conductivity under the synergistic effect. Improve sensor performance through synergistic effect, this combination of multi-component nanomaterials may provide higher electron conduction efficiency and current response rates. The electrochemical sensors, which were doped with various nanomaterials, were thoroughly investigated utilizing electrochemical impedance spectroscopy (EIS) in conjunction with time–current curve analysis. The findings demonstrated that the MXene/MWCNT-AuNPs/Fe 3 O 4 NPs nanocomposites possess a substantial specific surface area, an abundance of active sites, and enhanced electrical conductivity, all of which contributed to the improved conductivity and current response of the enzyme electrode. The resulting biosensor demonstrated superior sensitivity and selectivity for choline detection compared to previously reported electrodes. Specifically, it exhibited a linear range of 0.033–133.33 μM, a sensitivity of 8.8nA/μM, a response time of 5 s, and a detection limit of 22 nM. Importantly, the sensor showed high accuracy in detecting choline levels in human serum and cerebrospinal fluid samples, indicating its potential for practical applications in real-world clinical settings. This advancement holds promise for the effective prevention of the recurrence of glioma, Alzheimer’s disease, Parkinson’s disease, and other related conditions.