An enhanced impedance cytosensor based on folate conjugated-polyethylenimine-carbon nanotubes for tumor targeting

We present an enhanced and highly sensitive impedance cytosensor on the basis of folate conjugated-polyethylenimine-carbon nanotubes (folate-PEI-CNT). Zeta potential measurements and UV–vis spectroscopy have been employed to characterize the surface modifications of folate-PEI-CNT. We next investigated the efficiency of this probe for screening HeLa cells whose surfaces over-express folate receptors. The detection results have been further demonstrated by using scanning electron microscopy (SEM). Finally, we investigated the sensitivity of this impedance cytosensor with a detection limit of approximately 90 cells mL− 1 according to 3δ rule, as well as a linear detection range from 2.4 × 102 to 2.4 × 105 cells mL− 1.

► A simple method is introduced to synthesize folate-conjugated PEI-CNT nanocomposites.
► The folate-linked nanocomposites enhance detection sensitivity and specificity.
► The cytosensor showed a wide linear detection range for quantifying HeLa cells.
► The strategy could be further used in the early diagnostics of cancer.