A self-assembled peptide nanotube–chitosan composite as a novel platform for electrochemical cytosensing

A novel peptide nanotube and chitosan composite (PNT–CS) is prepared by self-assembly of dipeptide monomers in a CS aqueous solution. A scanning electron microscopy image showed that the composite had a three-dimensional (3D) network structure. Contact angle analysis indicated good hydrophilicity of the PNT–CS. X-ray diffraction patterns and FT-IR spectra revealed that the basical crystallinity properties and assembled manner of the PNTs in the composite could be maintained. Electrochemical characterization demonstrated that the PNT–CS had good conductivity and excellent stability during the electrochemical measurements. The composite combined the advantages of the two constituent materials and was further employed as an electrochemical cytosensor for the detection of cancer cells (K562). The linear range from 5 × 10³ to 5 × 10⁷ cells mL⁻¹ with a detection limit of 630 cells mL⁻¹ was obtained at the PNT–CS-modified electrodes using the electrochemical impedance method. These results are comparable with the previously reported cytosensors based on conventional nanomaterials. Nevertheless, the present method is very simple and suitable for down-up fabrication. The combination of the electrochemical properties, easy preparation, and excellent biocompatibility makes the PNT–CS a promising platform for next generation cytosensors.