Nanocomposites and nanomaterials

Impedimetric measurements during DNA hybridization on molecular-semiconductor electrodes 
based on CdS semiconductor nano-crystals or
 nanostructured surface of titanium oxide

Rachkov A.E.1, Pyeshkova V.M.1, Nesterenko Y.O.1,   Dobrovolskiy A.M.2, Schurenko A.I. 2, Khomich V.A. 2,   Kukla A.L.3, Mamykin A.V. 3, Bortchagovsky E.G.3, Doroshenko T.P. 3, Grynko D.A. 3

1 Institute of Molecular Biology and Genetics, National Academy of Sciences of Ukraine, 150, Zabolotnogo Str., Kyiv 03143, Ukraine
2 Institute of Physics, National Academy of Sciences of Ukraine, 46, Nauki Av., Kyiv 03028, Ukraine 
3 V.Ye. Lashkaryov Institute of Semiconductor Physics, National Academy of Sciences of Ukraine, 41, Nauki Av., Kyiv 03028, Ukraine 
E-mail: dgrynko@gmail.com

Detection of specific sequences of nucleic acids of pathogens such as viruses and bacteria is very important for early diagnosis of infectious diseases and the development of effective therapeutic strategies. Therefore, the Institute of molecular biology and genetics of NASU develops hybridization DNA sensors based on the specific binding of target DNA with corresponding oligonucleotides-probes, previously immobilized on the sensor surface. For the formation of sensor signals surface plasmon resonance spectroscopy or electrical impedance spectroscopy (EIS) are used. The standard way to increase the sensitivity of EIS is the use of electrodes with developed surface. But the standard approach for  EIS and quartz microcantileveris are costly nanomechanics technologies for production of structures with relevant nanosize. At the same time at the Institute of semiconductor physics of NASU and at the Institute of physics of NASU technologies are developing for creation of brushes of semiconductor crystal whiskers by condensation from the gas phase and porous surface of titanium oxide by anodic oxidation. In contrary to nanomechanics approach "top-down" to produce submicrometer structures, these technologies create structures by "bottom-up" approach, what significantly reduces the cost of production of relevant structures with submicrometer or even nanometer size. The test of the possibility to use such structures with developed nanostructured surface as electrodes for EIS demonstrated the decrease of the minimum detection limit to 10-12 M for hybridization of complementary oligonucleotides at the frequency 10 MHz.  The novelty of this project is the use of new electrodes with a developed surface in the form of nanostructured molecular-semiconductor systems for EIS. 
 This work was supported by National research foundation of Ukraine, project 2020.01/0504.