IBM building microchip to read human DNA and advance
20 October 2009
IBM scientists are designing a microchip with nano-sized holes
that could thread single strands of DNA and read the genetic code as the
strand passes through.
This advanced research effort to demonstrate a silicon-based "DNA
Transistor" could help pave the way to read human DNA easily and
quickly, generating advancements in health condition diagnosis and
The challenge in the effort is to slow and control the motion of the
DNA through the hole so the reader can accurately decode what is in the
DNA. If successful, the project could improve throughput and reduce cost
to achieve the vision of personalized genome analysis at a cost of $100
to $1,000. In comparison, the first sequencing ever done by the Human
Genome Project (HGP) cost nearly $3 billion.
Having access to an individual's personal genetic code could advance
personalized medicine by using genomic and molecular data to facilitate
the discovery and clinical testing of new products, and help determine a
person's predisposition to a particular disease or condition.
A team of IBM scientists from four fields — nanofabrication,
microelectronics, physics and biology — are converging to master the
technique that threads a long DNA molecule through a three nanometer
wide hole (see diagram on right), known as a nanopore, in a silicon chip. A nanometer is one
one-billionth of a meter or about 100,000 times smaller than the width
of a human hair.
Animation of DNA transistor reading a strand of DNA
As the molecule is passed through the nanopore, it is ratcheted one
unit of DNA at a time, as an electrical sensor "reads" the DNA. This
sensor that identifies the genetic information is the subject of intense
ongoing research. The information gathered from the reader could be used
to gain a better understanding of an individual's medical makeup to help
further the pursuit of personalized healthcare.
"The technologies that make reading DNA fast, cheap and widely
available have the potential to revolutionize bio-medical research and
herald an era of personalized medicine," said IBM Research Scientist
Gustavo Stolovitzky. "Ultimately, it could improve the quality of
medical care by identifying patients who will gain the greatest benefit
from a particular medicine and those who are most at risk of adverse
IBM Research is working to optimize a process for controlling the
rate at which a DNA strand moves through a nano-scale aperture on a thin
membrane during analysis for DNA sequencing. While scientists around the
world have been working on using nanopore technology to read DNA, nobody
has been able to figure out how to have complete control of a DNA strand
as it travels through the nanopore. Slowing the speed is critical to
being able to read the DNA strand. IBM scientists believe they have a
unique approach that could tackle this challenge.
To control the speed at which the DNA flows through the
microprocessor nanopore, IBM researchers have developed a device
consisting of a multilayer metal/dielectric nano-structure that contains
Voltage biases between the electrically addressable metal layers will
modulate the electric field inside the nanopore. This device utilizes
the interaction of discrete charges along the backbone of a DNA molecule
with the modulated electric field to trap DNA in the nanopore.
By cyclically turning on and off these gate voltages, scientists
showed theoretically and computationally, and expect to be able prove
experimentally, the plausibility of moving DNA through the nanopore at a
rate of one nucleotide per cycle — a rate that IBM scientists believe
would make DNA readable.
A human genome sequencing capability affordable for individuals is
the ultimate goal of the DNA sequencing and is commonly referred to as
Video of IBM scientists describing the project
In 2005, IBM revised its corporate privacy and equal opportunity
policies to reflect the corporation's intention to handle information
about an employee's genetics with a high regard for its privacy, and
also to refrain from using genetic test information to discriminate
against a person in the employment context. At that time, IBM was
arguably the first company in the world to restrict genetic data from
being used to make employment-related decisions.
In 2008, the United States signed into law the Genetic Information
Nondiscrimination Act (GINA) that protects Americans against
discrimination based on their genetic information when it comes to
health insurance and employment. The bill passed the Senate unanimously
and the House by a vote of 414 to 1. The long-awaited measure, which has
been debated in Congress for 13 years, is helping to pave the way for
people to take full advantage of the promise of personalized medicine
without fear of discrimination.