Embed Size (px)
Citation preview
Fahri Emre Ozturk1,2, Abubakar Isa Adamu1,2, Adem Yildirim1,2, Mehmet Kanik 1,2, Mehmet Bayindir1,2,3
1UNAM - National Nanotechnology Research Center, Bilkent University, Ankara, Turkey2Institute of Materials Science and Nanotechnology, Bilkent University, Ankara, Turkey
3Department of Physics, Bilkent University, Ankara, [email protected]
REFERENCES[1] F. E. Öztürk, A Yildirim, M. Kanik, M. Bayindir, Appl. Phys. Lett. 2014, 105, 071102
[2] A. Yildirim, F. E. Öztürk, M. Bayindir, Anal. Chem., 2013, 85, 6384
[3] M. Yaman, A. Yildirim, M. Vural, M. Bayindir, et. al. Anal. Chem., 2012. 84, 83
[4] A. Yildirim, M. Vural, M. Yaman and M. Bayindir, Adv. Mater., 2011, 23, 1263
[5] M.Shirasu, K.Touhara,, J. Biochem. 2011,150, 257
SUPPORTS
INTRODUCTION OPTOELECTRONIC NOSE
CONICAL BRAGG FIBERS: NARROW PHOTONIC BAND WAVEGUIDES FOR
BREATH ANALYSIS
CONCLUSION & FUTURE WORKS
NARROW BAND CONICAL BRAGG FIBERS
Artificial olfaction systems mimick the operation of biological systems with an array of transducers.
Optoelectronic nose system incorporates an array of hollow core Bragg fibers to measure infrared absorption of volatile molecules.
Mammalian nose uses joined response from different types of receptor proteins to determine odors sensitively and precisely in a severly complex background with thousands of various volatile molecules.
The joined response of the Bragg fiber array scans the whole midinfrared region for absorption bands of chemicals.
Measuring transmission intensity of each fiber before and after the analyte introduction to the hollow core allows to sense and identify virtually any chemical. The output signal for a chemical can be transformed directly to digital code to simplfy the analysis.
Studies in biochemistry and on novel artificial nose technologies paves the way for quick, cheap and remote diagnosis tools. Besides the diabetes diagnosis and monitoring, there are ongoing studies for many metabolic disorders such as gout, bladder infection, congestive heart failure etc. However, breath analysis is still not an established diagnostic or monitoring method in clinical applications. The limitations on sensitivity and selectivity of currents artificial olfaction devices hinder their potential biomedical applications. We expect the proposed method to provide better performance in opto-fluidic breath analysis schemes that utilize hollow core photonic band gap fibers.
Nor
mal
ized
tra
nsm
issi
on (
a.u.
)
Acetone
Standard fiber
Conical fiber(17% Diameter reduction)
Wavelength (µm)
Diameter reduction (%)
Fib
er r
espo
nse
(%)
The relation between bodily odors and diseases is known since the time of ancient physicians such as Hippocrates. Human body produces numerous volatile organic compounds which are exhaled through breath. These trace gases are the end products of various metabolic functions. Thus, they are potential sources of information for biological and chemical activities of the body.
Two prominent examples are lung cancer and diabetes studies. Acetone levels in the breath of healthy and diabetic humans differ in ppm levels, and the concentrations of many volatile organic compounds differ in ppb levels between healthy humans and lung cancer patients. With the biomedical applications of artificial olfaction devices, it could be possible to make reliable diagnosis by just taking a breath sample.
Bragg fibers with narrow bandgaps are favorable for chemical sensing and artificial olfaction in terms of improved selectivity and fiber response. Here, we engineered the photonic bandgap of Bragg fibers to achieve narrow band transmission, through establishing a gradient of interior multilayer dielectric mirror thicknesses along conical shaped fibers.
Fundamental bandgap was more than twofold narrowed, and higher order bands were completely eliminated in conical Bragg fibers. Sensing performance of conical fibers was enhanced in acetone vapor detection simulations due to narrowing of the fundamental band and elimination of higher order bands.
