This project aims to pave the way for long read-length, low-cost, high-speed, purely-electronic DNA sequencing. A carbon nanotube-based sensor will be developed in which a few-nanometer-diameter nanotube is aligned to a few-nanometer solid-state nanopore, through which DNA can be electrophoretically driven. The alignment of the nanopore to the nanotube will enforce a sequential interaction between the DNA strand and the nanotube as the DNA is driven through the pore. Because the voltage driving the DNA through the nanopore is decoupled from the electrical current in the nanotube-based sensor, translocation can be driven at smaller voltages, and thus lower translocation speeds than those accessible in purely ionic-detection-based nanopore devices. The low capacitance and large conductance of these nanotube-based sensors allows for local, single-charge sensitivity at bandwidths in excess of 1 MHz. There are two immediate aims for this project. Firstly, this work aims to detect DNA as it passes through a nanopore by simultaneously measuring ionic current through the nanopore and monitoring the nanotube sensor?s conductance response, as a proof- of-principle for nanotube-based sensing. Secondly, it aims to distinguish between double-stranded ?labels? attached to single-stranded DNA, as a means to study the sensitivity of these devices. This research may lead to low-cost point-of-care medical diagnostics based on electrical detection of labels attached to DNA, and in the longer-term, to low-cost DNA sequencing.
Genetics are known to play a role in susceptibility to disease and response to treatment, but obtaining genetic information for individual patients using current technology is often too costly in time and money. This research works to overcome this challenge by developing a simpler DNA-sequencing device in which a nanoscale electrical wire detects DNA as it passes rapidly through an adjacent hole in a membrane. The device is made using materials, methods, and electronics from the semiconductor industry to maximize reliability and minimize cost.
