Nanotechnology designed platform for DNA microarray applications using carbon nanotubes

Recent advances in nanotechnology have made it possible to use carbon nanotubes as high-gain single-molecule sensors in Lab-on-a-Chip (LOC) microarray units. More specifically, directed single point defects can be created to design a binding site on the nanotube. The binding of a single molecule (e.g., DNA, RNA) to this single site modulates the conductance of the nanotube to a measurable extent, leading to a very highly specific sensitivity. For example, a measured change in the nanotube's conductance due to a bound single-stranded DNA is sensitive enough to detect the presence of a complementary DNA target. This nano-scale detection system is called a single-molecule field-effect transistor (smFET). By creating an array of smFETs with different probes attached to each nanotube, this will allow for the development of an LOC microarray the size of a USB memory stick.

smFET microarray systems provide high sensitivity and multiplex capability to rapidly analyze samples for the presence of specific DNA / RNA with no need for amplification

This microarray platform has the potential to deliver qPCR levels of sensitivity without amplification, while delivering the degree of multiplexing characteristic of current DNA microarray technology. This method uses transduction (which is label-free), further simplifying sample preparation protocols by eliminating the need to design florescent labels, which is commonly used in current methods. This transduction approach allows arbitrarily low levels-of-detection (single molecule level) to be achieved, limited only by "incubation" times. By integrating this system with a complementary metal-oxide semiconductor (CMOS) integrated circuit, this LOC microarray can provide the detection of 500 unique nucleic acid sequences on a portable unit the size of a USB memory stick.

The concept of this technology has been demonstrated using thermodynamic and kinetic studies of DNA hybridization published in Nature Nanotechnology.

Lead Inventor:

Kenneth Shepard, Ph.D.

Patent Information

Patent Issued

• Can be used for label-free single-molecule detection.
• A new method for genomic diagnostics.
• Development of microarrays that can detect and quantify low levels of pathogenic DNA / RNA
• Potential design for a portable, low-cost option for point-of-care diagnostics
• Design of advanced high-throughput DNA sequencing
• Study of chemical kinetics, reaction dynamics, biomolecular processes, biomolecule rotation on tethers
• Analysis of water quality, other environmental monitoring.
• Food safety analysis and other microbial and public health risk assessments.

Advantages:

• Improved yield and sensitivity due to real-time monitoring of conductance fluxes.
• Does not require labeling or significant sample preparation, like qPCR.
• In contrast to qPCR, thousands of gene targets can be tested at low levels of detection in parallel.
• In contrast to existing single-molecule detection systems, this technology does not rely on fluorescence.
• A smFET microarray is significantly more portable than qPCR units

Patent information:

Patent Pending (WO/2013/158280)

Patent Pending (WO/2013/154750)

Tech Ventures Reference: IR CU12289

Related Publications:

• S. Sorgenfrei, C.Y. Chiu, R. L. Gonzalez Jr., Y.J. Yu, P. Kim, C. Nuckolls, K.L. Shepard. Label-free single-molecule detection of DNA-hybridization kinetics with a carbon nanotube field-effect transistor. Nat. Nano., Vol. 6, Issue 2, Jan. 2011, pp. 126-132.