Ultrasonic Nanotechnology to Improve Diagnosis
June 12, 2009 – 2:00 am
The new technique being developed by researchers at the University of Nottingham will utilise ultrasound technology to look inside cells. The components of the new technology would be many thousand times smaller than current systems.
The work by the Ultrasonics Group in the Division of Electrical Systems and Optics is considered so potentially innovative that it has been awarded a £850000 five-year Platform Grant by the Engineering and Physical Sciences Research Council.
Medical ultrasound uses an electrical transducer the size of a matchbox to produce sound waves at frequencies approximately 100–1000 times higher than those detectable by the human ear (typically 20 kHz). The Nottingham researchers are aiming to produce a miniaturised version of this technology, with transducers so tiny that 500 could fit cross the width of one human hair; these would produce sound waves at frequencies a thousand times higher again, in the GHz range.
Dr Matt Clark of the Ultrasonics Group said, “By examining the mechanical properties inside a cell there is a huge amount that we can learn about its structure and the way it functions. But it’s very much a leap into the unknown as this has never been achieved before.
“One of the reasons for this is that it presents an enormous technical challenge. To produce nano-ultrasonics you have to produce a nanotransducers, which essentially means taking a device that is currently the size of a matchbox and scaling it down to the nanoscale. How do you attach a wire to something so small? Our answer to some of these challenges is to create a device that works optically, using pulses of laser light to produce ultrasound rather than an electrical current. This allows us to talk to these tiny devices.”
To create the device the group is leveraging a technology developed at the University called Cheap Optical Transducers (CHOTS). The CHOT transducer is used in this case to generate and/or detect the ultrasound, but instead of being operated electrically like a traditional transducer it is operated using a laser. “We have developed this CHOT technology in many directions and one is to shrink them as far as we can go and it turns out you can go a very long way down to the nanoscale,” reports Dr Clark.
“As ultrasonics goes down in scale it goes up in frequency. The nano-CHOT technology operates at frequencies 1-100 GHz although the highest frequency prototype device we have made so far was around 10 GHz,” he says.
Dr Clark continues, “We propose to overcome the problem of the massive attenuation by placing the transducers directly in or on the sample. So in the case of cells we can insert the transducers into the cells and because they are so small this [will be] well tolerated and then we can probe them using lasers, which pass harmlessly through them.”
How could this lead to very early diagnosis of diseases? Dr Clark responds: “It is well known that structural changes occur in diseased tissues and these changes stem from changes in the cells, just probing the structural changes in the cells might lead to new diagnostic techniques for instance for bone cancers. In addition to this, ultrasonic devices are widely at the heart of chemical sensors (for example, SAW devices in electronic noses). We can sensitise our transducers in exactly the same way so we can probe the chemical environment in the cells and tissue.
“We also think we might be able to measure other things, for instance we think we can produce chemically active force sensors that would allow us to bind the transducers to parts of the cells and measure the forces and interactions taking place.”
In addition to medical applications, the new technology would have important uses as a testing facility for industry to assess the integrity and quality of materials and to detect tiny defects that could have an impact on performance or safety. Ultrasonics is currently used in the aero industry.
The group is also seeking to develop new inspection techniques for inspecting engineering metamaterials, that is, advanced composites that are currently impossible to inspect with ultrasound. These materials offer huge performance advantages allowing radical new engineering, but can’t be widely used because of the difficulty of inspection.
Dr Clark added, “We are also applying our technology to nanoengineering … As products and their components become ever tinier, the testing facilities for those also need to be scaled down accordingly. In nanoelectromechanical and microelectromechanical based machines there is an increasing demand for testing facilities that offer the same capabilities as those for real-world sized devices.”
More information is available from Dr Matt Clark at tel. +44 115 951 5536, email: matt.clark@nottingham.ac.uk.
Annie Ellerton
Tags: nanotechnology, Ultrasound, University of Nottingham
