Nucleic acid detection with a nanogap electrical sensor

Abstract

Systems and methods to detect a polynucleotide strand in a sample during the early stage of amplification cycles. A metal-insulator-metal (MIM) electrode unit with two metal electrodes separated by a dielectric layer may be utilized as a nanogap sensor. Primers for amplifying a target polynucleotide strand may be immobilized on the surface of the dielectric layer. Polymerases, nucleotides, templates and primers may be added to the sample. At least one type of nucleotide may be labeled with a redox label that may enhance electron transport through the nanogap via tunneling and/or diffusion-based redox cycles. Signals (e.g., voltage pulses) may be directed through each of the electrodes. Current values from each electrode may be measured to establish a baseline signal. Alterations in the baseline signal may indicate the presence of target polynucleotide strands. The time to detect an alteration in the baseline signal may facilitate quantification of target polynucleotide strands.