Nanogap-based electrical PNA chips for the detection of genetic polymorphism of cytochrome P450 2C19.

PNA chips for the detection of the genetic polymorphism of Cytochrome P450 2C19 (CYP2C19), a well-known enzyme related to the metabolism of therapeutic drugs, were electrically-interfaced with interdigitated nanogap electrodes (INEs). The average gap distance and effective length of the INEs were about approximately 70 nm and approximately 140/m, respectively. Those INEs having the aspect ratio of about 2000, were prepared by the combination of the photolithography (for the formation of initial electrodes) and the surface-catalyzed chemical deposition (for the gap narrowing), without the e-beam lithography. The PNA probes for the detection of CYP2C19 were immobilized in the gap region of INEs via Schiff base formation. The I-V characteristics clearly showed a sharp increase in the conductance between the nanogap electrodes upon the PNA-DNA hybridization, followed by the adsoprtion of functionalized Au nanoparticles. Four different target DNAs for the diagnosis of CYP2C19 polymorphism were successfully detected and discriminated with the INE-based PNA chips.