Low-cost Nano-spike Bio-Impedance Sensor (NBIS) without surface functionalization for detection and phenotyping of cancer cells

We report a low-cost Nano-spike Bio-Impedance Sensor (nBIS) for detection and phenotyping of cancer/non-cancer cells (HeLa, MCF7 and HEK293). 3D self-aligned nano-spikes, fabricated on a thin aluminum substrate by nanoimprint and electrochemical anodization, were used to measure electrical impedance of cancer cells without surface functionalization. The impedance spectra of cancer and non-cancer cells show significant differences. From the modified Randle's model, nano-spike electrodes can significantly reduce electrochemical and polarization problems at the electrode and liquid interface. The limit of detection (LOD) of nBIS was 10 cells/mL. The normalized charge transfer resistance (20–30% difference among different cells) Rct was shown to be a promising electric biomarker for cancer cell detection and phenotyping.