BUFFALO, N.Y. -- How do you create a sensor that can "sniff" out
diseases based on the highly complex odors that come out of our
You base it on the real thing, according to University at
They are developing a rugged, inexpensive Breathalyzer-type
device that, just like the nose of a human -- or other mammal --
will contain thousands of chemical sensors "trained" to recognize
complex chemical patterns, some of which are known biomarkers for
"These volatile biomarkers are free for the asking and taking,"
said Frank V. Bright, Ph.D., UB Distinguished Professor in the
Department of Chemistry in the College of Arts and Sciences, A.
Conger Goodyear Professor of Chemistry and principal investigator.
"They emanate from us all of the time. They are large in volume,
much safer to handle than biofluids and available through totally
Called gaseous metabolites, these are the same odors that some
animals use to identify their offspring, owners, mates, prey or
So far, multiple volatile chemicals have been detected by other
scientists as biomarkers, correlating their presence and
concentration with human diseases ranging from diabetes and AIDS to
lung cancer and various mental illnesses.
But current methods of detecting these chemicals in human breath
and other odors require cumbersome and elaborate laboratory
instruments, such as gas chromatographs, which would be
prohibitively expensive and inappropriate for clinical, home or
remote field settings.
That's why the UB team is taking a multidisciplinary approach,
integrating research in neural networks, pattern analysis, novel
sensor technologies, low-power optical detectors and light sources
with clinical expertise.
Such a speedy, inexpensive tool for early screening of multiple
diseases could improve dramatically the health and longevity of
millions of Americans, especially the elderly, and those in
income groups, in whom diseases often are diagnosed at later
stages, Bright said, in part due to economic issues and poor
The UB team, members of which have developed some of the world's
most stable and robust sensors, including some that do not need any
calibration for more than two years, may be the first to integrate
chemists, clinicians, computer scientists and engineers to exploit
the full potential of expired gases or odors from human breath or
other parts of the body to diagnose diseases.
Based in UB's Center for Unified Biometrics and Sensors (CUBS),
the research, recently funded by a $400,000 grant from the John R.
Oishei Foundation of Buffalo, is in the emerging field of
metabolomics, the real-time study of metabolites, substances
produced through metabolism.
Metabolomics technology has been identified as a focus for
research in the National Institutes of Health Roadmap initiative;
within the next two years, NIH plans to establish centers and
programs in metabolomics.
While there are other electronic "noses" already on the market,
they cannot correlate reliably their read-outs to a particular
disease state, Bright said.
"The UB device will be unique because it will be designed to
exploit, and in some ways mimic, the concepts of olfaction," he
continued. "Despite the fact that we might encounter numerous
really smelly things in our lifetime, it is not as if there are
billions of discrete sensors within our noses that nature designed
a priori to respond selectively to every possible smelly odor.
"Rather, there are suites of receptors in our nasal passages and
the collective response from all of these receptors to an odor or
set of odors can be discriminated," he said.
In the same way, the UB device will contain individual chemical
sensors, perhaps as many as a million, which collectively will
produce a pattern revealing the chemical signature of a patient's
breath, which may be related to a particular disease state.
That pattern will then be used to "train" neural networks,
groups of connected artificial neurons capable of learning new
information, to discriminate potentially between patients with
"The power of neural networks in this research is that they will
pull out the important features and save them so that when they are
exposed to a chemical pattern they have 'seen' before, the device
will elicit the right response," said Albert H. Titus, Ph.D.,
assistant professor of electrical engineering in the UB School of
Engineering and Applied Sciences and a co-investigator on the
He added that with neural network processing, the size of the
sensor elements can stay very small, each measuring about 10
micrometers in size, a critical element for the inexpensive,
low-power device the UB team is designing.
Titus is building novel, complementary metal oxide semiconductor
(CMOS) arrays that simultaneously will read the signals produced by
each of the sensor elements.
"The issue with this application is can you come up with a
unique ensemble of sensor elements that exhibit enough diversity to
respond to a large variety of small, chemically similar species to
give you a chance of realizing the chemical fidelity that you
need?" asked Bright.
To achieve that fidelity, he said the chemical sensors will be
made out of xerogels, porous glass-like materials that consist of
easily tailored nanoscopic pores, which can be tuned to recognize
specific chemicals or classes of chemicals.
Bright's lab is well-known for its work developing chemical
sensors out of xerogels that detect chemicals in blood, urine and
So far, he and his associates have developed xerogels that can
respond to about 100 different chemicals, ranging from small
molecules like oxygen and carbon dioxide to mid-sized molecules
like steroids and prostaglandins up to big proteins like
Bright explained that the envisioned device will work as
follows: As the breath sample flows through the breath-testing
device, the individual sensing elements will change their color or
intensity; those changes will be detected by the CMOS array,
producing electrical signals that then can be processed by the
The ultimate goal is to produce an extremely robust and
reliable, low-cost, handheld device encompassing all of the
sensing, detection and processing elements.
In addition to Bright and Titus, co-investigators include
Alexander N. Cartwright, Ph.D., professor of electrical
engineering, and Venu Govindaraju, Ph.D., director of CUBS and
professor of computer science and engineering, both in the School
of Engineering and Applied Sciences, and Wesley L. Hicks, Jr.,
D.D.S., M.D., professor of otolaryngology and neurosurgery in the
School of Medicine and Biomedical Sciences and attending surgeon at
Roswell Park Cancer Institute.
"The Oishei Foundation's generosity will enable our team to have
a prototype ready for clinical testing within a year," said
The clinical testing will be done at Roswell Park Cancer
The John R. Oishei Foundation's mission is to enhance the
quality of life for Buffalo-area residents by supporting education,
health care, scientific research and the cultural, social, civic
and other charitable needs of the community. The foundation was
established in 1940 by John R. Oishei, founder of Trico Products
The University at Buffalo is a premier research-intensive public
university, the largest and most comprehensive campus in the State
University of New York.