Folic Acid Functionalized Vertically Aligned Carbon Nanotube (FA-VACNT) Electrodes for Cancer Sensing Applications

An electrical cancer biosensor was developed using amine-functionalized vertically aligned carbon nanotubes (VACNTs) conjugated to folic acid (FA) molecules. Specific binding of FA to folate receptor (FR) existing on the membrane of cancer cells assisted their entrapment on VACNTs. For the conjugation of FA to CNTs, amine (NH2) functional groups were attached to the side walls of the nanotubes by plasma treatment. The amount and shape of entrapped cancer cells on FA-VACNTs were noticeably higher and more uniform than the cells entrapped on bare VACNTs. The comparative signal spike of the FA-VACNTs and VACNTs covered impedance sensor in interaction with the same concentration of lung cancer cells (QUDB) showed sharper response for the functionalized sensor. Moreover, electron microscopy and florescent images as well as impedance diagrams verified the spherical and non-deformed shape of the cells entrapped by FA-VACNT. This sensor would be useful in assaying the cells vitality in time evolution. This device could be applied in diagnostic and time monitoring applications in the field of cancer such as extreme drug resistance assay (EDR).