Nanobiotechnology for healthcare 
Highly efficient biologically functionalized semiconductor electrodes based on nanostructured titanium oxide                     for DNA sensors
Shchurenko A.I.1,  Styopkin V. I. 1, Mamykin A.V.2,  Kukla O.L.2,	         Nesterenko E.O.3 , Pyeshkova V.M.3 ,  Grynko D.O.2,3
1 Institute of Physics  NAS of Ukraine. Prospect Nauki, 46, Kyiv-03028, Ukraine. 
2 V.E. Lashkaryov Institute of Semiconductor Physics NAS of Ukraine. Prospect Nauki, 41, Kyiv-03680, Ukraine.
3 Institute of Molecular Biology and Genetics  NAS of Ukraine. Zabolotnogo Str., 150, Kyiv-03143, Ukraine.			E-mail: dgrynko@gmail.com

A new low-cost technology for the production of porous nanostructured semiconductor electrodes is proposed [1], which may be the basis for the production of highly informative DNA sensors. Functionalization of such electrodes with a predetermined oligonucleotide provides selectivity of hybridization with the corresponding nucleotide sequence of DNA (target DNA). As a basis for such a sensor is used porous film of anodically oxidized titanium with different morphology (nano-tubs with a depth of 0.3 to 7 μm and a diameter of 200 to 400 nm). Technique of immobilization  oligonucleotides on the porous titanium oxide films with thiolated oligonucleotides and low molecular weight thiols for the detection of specific nucleic acid sequences with impedance spectroscopy have been  tested at presented report.
 The process of hybridization of oligonucleotide P1, which is complementary to modPh, on the surface of nanostructured titanium oxide with the immobilized modPh layer is demonstrated. Range of experimentally tested P1 concentrations was 0.001 - 10 nM in SSC buffer solution. Peculiarities of interaction are investigated for immobilized probe oligonucleotide modPh with complementary (P1), partially complementary (BCRex14) and non-complementary (npt02) nucleic acid sequences. 
The linear dynamic range of the developed DNA sensors is 0.001 - 10 nM. It is shown that the use of such electrodes provides the ability to reduce the limit of determination of specific nucleic acid sequences to 0.001-0.1 nM. 

1.	A. I. Schurenko, V. I. Styopkin, D. O. Grynko, and A. M. Dobrovolskiy, Self-Organized Anatase-Nanotubes’ Array // Nanosistemi, Nanomateriali, Nanotehnologii. - 2020.-V. 18, № 3, P. 529–539