Nanobiotechnology for health-care
Nanobiosensing with antioxidant biomarkers using microwave WGM resonance technique
Naumova N.V.1,3, Hlukhova H.O.2,3, Gubin A.I.2, Vitusevich S.A.3
1 Institute of Biology and Medicine, Taras Shevchenko National University of Kyiv, Ac. Hlushkova Ave., 2, Kyiv-03022, Ukraine. 
E-mail: naumova.kandaurova@gmail.com
2 Usikov Institute for Radiophysics and Electronics, NAS of Ukraine, Ac. Proskury Str., 12, Kharkiv-61085, Ukraine.
3 Institute of Complex Systems, Forschungszentrum Jülich, 52425 Jülich, Germany

Today, antioxidant (AO) biomarkers are widely used in biological studies in vivo and in vitro in medical and environmental biosensor technologies, and there- fore their characterization in terms of analytical sensitivity, specificity and validity/ utility is vitally important for practice. Among possible techniques suitable for non-destructive detection of biomolecules in situ, microwave (MW) whispering- gallery-mode (WGM) dielectric resonators with microfluidic channels is of our particular interest [1]. This approach provides many advantages, such as fast response, high sensitivity and selectivity, compatibility with optoelectronics, possibility of integration of biosensor arrays into a portable lab-on-chip analytical instrument and optimization for studying complex biological objects at nanoscale. In our work, we applied a high-Q MW WGM microresonator technique to study the biosensory properties of low-molecular-weight non-enzymatic antioxidants (ascorbate, glutathione) and antioxidant enzymes (catalase, superoxide dismutase) as biomarkers of stress reactions in living cells under biotic and abiotic stresses. By systematic measurements, we obtained a set of characteristic biosensor responses of the test substances at different concentrations in liquids and droplets of small volume. Our experiments showed quite good accuracy, stability and selectivity in the detection of AO biomolecules at the ng/nl level. The obtained results indicate the potential of AO biosensors and the prospects for express-diagnostics, monitoring and control of stress-related bioactivity in cells of plant, animal and human organisms. Research is in progress. Support of the German-Ukrainian scientific cooperation program is gratefully acknowledged.

1.	Gubin A. I. et al. Whispering-gallery-mode resonator technique with micro-fluidic channel for permittivity measurement of liquids // IEEE Trans MW Theory Techn.-2015.-63.-P. 2003-2009.