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Scientists at the University of Ulster are using nanotechnology to build new DNA biosensors which could be used in identifying genetic diseases, cancer research, identification of dangerous micro-organisms, and forensic science.
Dr Patrick Lemoine and Dr Tony Byrne from the School of Electrical and Mechanical Engineering at Ulster have teamed up with French biosensor expert, Professor Pascal Mailley from the CEA Grenoble research facility for the project.
The collaboration has been facilitated by a research grant from the Royal Society.
The aim of the project is to devise a DNA biosensor using new nanoscale fabrication techniques. The Nanotechnology and Integrated BioEngineering Centre (NIBEC) at Ulster has state-of-the-art facilities for nanomaterials research as well as the mix of disciplinary expertise – physics, chemistry, biology and engineering, required for such projects.
Man-made biosensors are usually small hand-held devices costing a few pounds, which can replace laboratory systems costing thousands of pounds. Some are already commercially available in pharmacies, such as blood/sugar measurement devices essential for diabetics.
What is not available is an equivalent biosensor to detect DNA – the long chain molecule hidden in human cells which holds the key to life and which provides an unique code for every individual on earth.
These devices can detect the presence of something biological—say, a minute amount of DNA in a virus—and then output a signal. DNA biosensors can theoretically be used for medical diagnostics (for instance, detecting a misspelling in a disease-causing gene), forensic science, agriculture, or even environmental clean-up efforts.
A significant advantage of DNA-based sensing devices is that no external monitoring is needed. How do they work? DNA biosensors are complicated mini-machines—consisting of sensing elements ("probes" that match up in sequence with the DNA to be detected), microlasers, and a signal generator, all in one. At the heart of DNA biosensor function is the fact that two strands of DNA stick to each other by virtue of chemical attractive forces.
On such a sensor, only an exact fit—that is, two strands that match up at every nucleotide position— gives rise to a fluorescent signal (a glow) that is then transmitted to a signal generator. Ideally, the sensor would be a tiny square of a chip that could be immersed in a test fluid—blood, for instance—to pick up traces of disease-causing bacteria or viruses.
Such a biosensor would present enormous opportunities. For example, DNA sequencing is necessary for the identification and treatment of genetic diseases, for cancer research, for the identification of dangerous micro-organisms or for forensic science.”
Dr Lemoine says: “The key idea of the proposal is to use specific techniques called ‘self-assembly' and ‘nano-patterning' to create arrays containing millions of pixels with very high surface areas.
This means that more DNA fragments can be immobilised in smaller geometric areas, typically a few millimetres square. When the ‘chip' is exposed to a sample of unknown DNA, the complementary strands join up, revealing the sequence of the unknown DNA.
This technology is not only applicable to DNA chips but might allow the production of biosensors using a wide range of bio-molecules which may be used as miniature implantable sensors for monitoring conditions within the body.
For example, the development of an artificial pancreas, which could both measure glucose and control insulin delivery, would be of major benefit to diabetics.
NIBEC - the Nanotechnology and Integrated BioEngineering Centre is a well established world-class research complex at the University of Ulster 's Jordanstown campus. NIBEC represents a consolidation of eight advanced functional materials research groups, dealing with thin-film material types used in electronics, photonics, nanotechnology, sensors, MEMS, optical, environmental, magnetic and bio-material devices.
The £10M purpose-built facilities house some of the most sophisticated nano-fabrication, biological and characterisation equipment in the world. Strong international collaborations have been developed and large infrastructural and project funding has been a highlight of this rapidly growing research area. The centre hosts major core research initiatives such as MATCH (EPSRC National Centre); CACR (UU and Royal Victoria Hospital ); NanotecNI (UU and QUB); and also the team have developed formal collaborations with numerous world-wide Institutions and Industry.
NIBEC is staffed by an internationally recognised team of researchers and academics working predominantly at the interface of bioengineering and nanotechnology. Technology transfer is a key objective and a number of successful spin-out companies have emerged from NIBEC in recent years, the most successful of these being Heartscape, HeartSine Technology and Sensors Technology and Devices Ltd (ST&D).
Source: University of Ulster /...
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