National Repository of Grey Literature 10 records found  Search took 0.01 seconds. 
Mathematical method for submolecular resolution of helicene-based macrocycles by atomic force microscopy in air
Ukraintsev, Egor ; Houska, Václav ; Vacek, Jaroslav ; Starý, Ivo ; Stará, Irena G. ; Rezek, B.
We introduce a straightforward mathematical method for improving the AFM image resolution, applied to image analysis of helicene-based macrocycles adsorbed on HOPG. The method reveals structural details from insufficiently resolved AFM images and attributes them to internal structure and ordering of the macrocycles. Our findings are also corroborated by molecular mechanics simulations, validating that the structure provided by the method has lower potential energy compared to other tested macrocycle arrangements.
Microscopic study of multifunctional drug molecule adhesion to electronic biosensors coated with diamond and gold nanoparticles
Finsterle, T. ; Pilarčíková, I. ; Bláhová, I.A. ; Potocký, Štěpán ; Kromka, Alexander ; Ukraintsev, Egor ; Nepovimová, E. ; Musílek, K. ; Kuča, K. ; Rezek, B.
The easy and fast detection of drug content and concentration levels is demanded in biological research as well as in clinical practice. Here we study on microscopic level how nanodiamonds and gold nanoparticles interact with a multifunctional drug molecule directly on a biosensor surface. The sensors are made of interdigitated Au electrodes coated by 5 nm hydrogenated or oxidized nanodiamonds and further combined with Au colloidal nanoparticles (size 20 nm) providing nanoscale composite (spacing 100 nm). Atomic force microscopy is employed to measure local tip-surface adhesion forces and surface topography. AFM adhesion maps show that the drug binds to all types of nanoparticles and the adhesion is also significantly influenced by the substrates on which the nanoparticles are deposited. Role of local AFM tip interaction with nanostructured surface is also discussed.\n
Growth of Escherichia coli on nanocrystalline diamond
Jurková, Blanka ; Kozak, Halyna ; Artemenko, Anna ; Ukraintsev, Egor ; Beranová, J. ; Konopásek, I. ; Kromka, Alexander
In this contribution, we compared the attachment of gram-negative model bacterium Escherichia coli to\nuncoated glass and glass coated by hydrogenated and oxidized NCD films. For attachment experiments,\ncontinuous cultivation in commercially available CDC Bioreactor was used. Antibacterial tests indicated\nhigher attachment of gram-negative model bacterium Escherichia coli to NCD surface compared to uncoated\nglass. We assign this effect to higher roughness of NCD surface compared to glass. Bacterial cells preferred\nthe hydrophobic surface of hydrogenated NCD surface to hydrophilic oxidized NCD for their attachment.
In situ XPS characterization of diamond films after AR.sup.+./sup. cluster ion beam sputtering
Artemenko, Anna ; Babchenko, Oleg ; Kozak, Halyna ; Ukraintsev, Egor ; Ižák, Tibor ; Romanyuk, Olexandr ; Potocký, Štěpán ; Kromka, Alexander
In this work, in situ XPS analysis of chemical composition of H- and O-terminated nano- and microcrystalline diamond (NCD and MCD) films before and after their sputtering by the Ar+ cluster ion beam was investigated. Scanning electron microscopy confirmed sputtering of all diamond surfaces with a rate about 0.5 nm/min. Raman spectroscopy and XPS revealed surface graphitization of diamond surface induced by sputtering. Moreover, XPS data showed the presence of about 0.7 % of Ar atoms on the investigated diamond surface after 66 min of sputtering. Also, oxygen residuals were still presented on the H-NCD surface after 66 min of sputtering. In contrast, no oxygen was found on the H-MCD surface just after 2 min of sputtering. Surface composition is discussed in respect to the diamond films growth parameters and surface structure.
Computational study of cellular assembly on hydrophobic/hydrophilic micro-patterns
Ukraintsev, Egor ; Brož, A. ; Kalbáčová, M.H. ; Kromka, Alexander ; Rezek, Bohuslav
We develop simple onedimensional stochastic model of cell behavior on chemically patterned surfaces that is based on three key parameters: speed of cell movement (motility) across substrate, probability of cell adhesion to substrate, and probability of cell division on substrate when adhered on substrate. Amount of adhered cells on hydrophobic and hydrophilic regions is calculated as function of time (number of cycles up to 2000). The model is correlated with in-vitro data obtained within 48 h in real time. We show that this simple stochastic model with the three parameters (where cell motility is the most important one) can describe with high accuracy the experimental data and thereby explain the observed preferential cell assembly on hydrophilic/hydrophobic micro-patterns (up to 200 um width).
Nanocrystalline diamond SG-FET: role of grain boundaries and cell culture process
Krátká, Marie ; Kromka, Alexander ; Ukraintsev, Egor ; Brož, A. ; Kalbáčová, M. ; Rezek, Bohuslav
Fetal bovine serum layer morphology and thickness is not changing (significantly). KFM measurement show that surface potential difference between diamond and gold reduces after each process. That result indiactes changes in surface termination. FET shifts possibly related with change of diamond itself.
AFM study of FBS, BSA, Fn proteins adsorbed on H-/O-diamond
Ukraintsev, Egor ; Kromka, Alexander ; Rezek, Bohuslav
Cell growth indicates that Fibronectin is behind micro-array formation. Using AFM we measured conformations of particular proteins from Fetal bovine serum in solution and in air. AFM data are not convincing.
Electrochemical growth of polypyrrole on boron doped diamonds
Ukraintsev, Egor ; Kromka, Alexander ; Haenen, K. ; Rezek, Bohuslav
To find out the mechanism of the electrochemical attachment of polypyrrole (Ppy) to diamond we grow Ppy layers on hydrogen and oxygen terminated boron doped diamond surfaces (BDD) using constant current applied between the BDD and the platinum wire.
Synthesis, structure, and opto-electronic properties of organic dies on diamond
Rezek, Bohuslav ; Čermák, Jan ; Ukraintsev, Egor ; Hubík, Pavel ; Mareš, Jiří J. ; Ledinský, Martin ; Fejfar, Antonín ; Kočka, Jan ; Kromka, Alexander
We prepare a thin-film heterojunction of polypyrrole (Ppy) on hydrogen-terminated diamond by electro-polymerization from solution. We combine advanced scanning techniques (AFM, KFM, micro-Raman) to characterize microscopic structural, chemical, and opto-electronic properties of such system.
Renewal of three-dimensional nanocrystalline diamond bio-transistor by low temperature hydrogenation
Krátká, Marie ; Neykova, Neda ; Ukraintsev, Egor ; Kromka, Alexander ; Rezek, Bohuslav
We employ directly grown microscopic (20um and 5um) solution-gated field-effect transistors (SGFET) as a biosensor with H-terminated surface acting as a gate insulator towards solution and generator of surface conductivity at the same time.

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