LAUSR

A sensitive, simple, label-free electrochemical cytosensor was developed to evaluate the anticancer activity of pinoresinol against human cervical carcinoma (HeLa) cells. HeLa cells were immobilised on carboxylated multi-walled carbon nanotubes (c-MWCNTs)/gold nanoparticles (AuNPs) nanocomposite-modified glassy carbon electrodes. Scanning electron microscopy, transmission electron microscopy, Fourier transform-infrared spectroscopy, and X-ray diffractometry were used to characterise the morphology, crystallinity, and composition of the nanocomposites. Cyclic voltammetry was used to characterise and optimise the cytosensor. Both c-MWCNTs and AuNPs increased the electron-transfer rate between the HeLa cells and the electrode, retaining good cell compatibility. The concentration of HeLa cells immobilised on the nanocomposite electrode exhibited a good correlation with the impedance values determined by electrochemical impedance spectroscopy in the range of 102-106 cells/mL (detection limit of 102 cells/mL) with R2 = 0.975. HeLa cells were then immobilised on the nanocomposite electrode at a concentration of 104 cells/mL, and it was used as a cytosensor. The anticancer activity of pinoresinol from Cinnamomum camphora was evaluated by determining the median inhibitory concentration using the proposed cytosensor. For comparison, a 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay, flow cytometry, and fluorescent imaging were simultaneously performed, which confirmed the results of the cytosensor. The cytosensor is promising for future applications in anticancer drug screening.