Detecting DNA on standard computer microchips

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Research perspective written by Nicholas Miscourides
Centre for Bio-inspired Technology, Institute of Biomedical Engineering, Department of Electrical & Electronic Engineering
Imperial College London, UK

How can I explain the importance of this research to the general public?

DNAs are formed out of four bases (A, C, G and T) that spell out sequences that define our individual characteristics, ranging from hair colour to how probable it is to develop an inherited disease (predisposition). Scientists believe that the ability to identify and classify the precise order of bases within a DNA molecule, called DNA sequencing, has a profound impact on our understanding of the life sciences and medicine. DNA sequencing has been particularly important for fields including cancer, human genetics and infectious diseases.

Traditionally, DNA sequencing requires expensive and bulky equipment as well as resource-rich laboratories. The methods described in this study eliminates the need for all of this by showing how rapid DNA detection can be carried-out on a semiconductor-based system, designed with the same process flow used to manufacture all standard computer microchips. As a result, DNA obtained from saliva samples can now be sequenced on a fingernail-sized microchip in as short as 30 minutes, showing that fusing DNA chemistry and commercial microchip technology is possible.

The ability to rapidly detect DNA from an individual using a disposable platform paves the way for truly personalised medicine, where individuals are treated based on their unique genetic traits. These platforms can revolutionise healthcare by facilitating personalised drug therapy, detecting specific genetic mutations and used as point-of-care diagnostic devices.

Why is this important for researchers in fields other than bioelectronics?

This work presents a pH-sensing semiconductor microchip capable of real-time detection and amplification of small amounts of nucleic acid. Using this technology, low-cost and disposable genetic sequencing platforms can be designed to provide rapid detection of specific sequences and single-nucleotide polymorphisms (SNPs). The microchip can be used to carry-out the two most popular DNA amplification techniques, namely PCR and LAMP, in a fraction of time than what is currently needed and can be a useful tool to molecular biologists and geneticists. Additionally, rapid DNA detection will be an irreplaceable tool towards the grand vision of personalised medicine in healthcare.

Why is this important for researchers in the same field?

This study presents an integrated circuit (IC or microchip) capable of detecting and amplifying in real-time the pH variations observed when DNA polymerisation takes place. The microchip relies on integrated Ion-Sensitive Field-Effect Transistors (ISFETs) to detect the variations in pH and forms a full system-on-chip platform. Both PCR and LAMP amplification techniques have been successfully demonstrated on the chip as well as discriminating single nucleotide polymorphism (SNP) variations of the cytochrome P450 family from human saliva. This work eliminates the need for bulky, external apparatuses for SNP discrimination thus enabling the creation of portable and low-cost platforms for DNA analysis.

Original article

Simultaneous DNA amplification and detection using a pH-sensing semiconductor system
Christofer Toumazou, Leila M Shepherd, Samuel C Reed, Ginny I Chen, Alpesh Patel, David M Garner, Chan-Ju A Wang, Chung-Pei Ou, Krishna Amin-Desai, Panteleimon Athanasiou, Hua Bai, Ines M Q Brizido, Benjamin Caldwell, Daniel Coomber-Alford, Pantelis Georgiou, Karen S Jordan, John C Joyce, Maurizio La Mura, Daniel Morley, Sreekala Sathyavruthan, Sara Temelso, Risha E Thomas & Linglan Zhang
Nature Methods, published online 9 June 2013

Acknowledgements

This work was carried-out by researchers at DNA Electronics Ltd and Imperial College London. The original text was published in Nature Methods in 2013.

Originally published at blog.sparrho.com.