Ignat Ignatov

Prof. Ignat Ignatov

Scientific Research Center of Medical Biophysics, Bulgarian Academy of Sciences, Tsarigradsko shosse blvd, bl. 2. Sofia, Bulgaria
orcid
I am a Professor and hold a DSc in Physics. My scientific di...

Research Focus & Metrics

Academic Career Length

12Years (2015-Present)

(Calculated once Scilit publication data is synced: current year − year of first publication + 1)

Representative Publications

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17 November 2022 in Cosmetics
Verified
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TPTeodora Petrova Popova
Teodora Petrova Popova
Ignat IgnatovIgnat Ignatov
Ignat Ignatov
Toshka PetrovaToshka Petrova
Toshka Petrova
MKMila Kaleva
Mila Kaleva
FHFabio Hüther
Fabio Hüther
SKStoil D. Karadzhov
Stoil D. Karadzhov
The antimicrobial effect of a cream containing extracts of African geranium (Pelargonium sidoides DC.), black elderberry (Sambucus nigra L.), and St. John’s wort (Hypericum perforatum L.) in colloidal nanosilver (AgNPs) at a concentration of 30 ppm, denoted as SILVER STOP® cream (SS® cream), was examined in vitro. The research was performed with Escherichia coli (ATCC and two clinical isolates), Staphylococcus aureus (ATCC and two clinical strains), and Candida albicans (ATCC and two clinical isolates). The agar-gel diffusion method and suspension tests for determination of the time of antimicrobial action of SS® cream were used. SS® cream showed significant antimicrobial activity. The Gram-negative microorganisms tested died in a much shorter time than the Gram-positive ones. In suspension with a density of 104 cells·mL−1, E. coli died for 1 min, the oval fungus C. albicans—after 10 min and S. aureus—after 60 min of exposure to SS® cream. The highest sensitivity was found in E. coli. The curative effect of SILVER STOP® cream was also examined in vivo in dogs with different skin diseases. The results showed successful healing of the diseases and a very good curative effect of the cream.

10 October 2022 in Plants
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Ignat IgnatovIgnat Ignatov
Ignat Ignatov
FHFabio Hüther
Fabio Hüther
NNNikolai Neshev
Nikolai Neshev
Yoana Kiselova-KanevaYoana Kiselova-Kaneva
Yoana Kiselova-Kaneva
TPTeodora Petrova Popova
Teodora Petrova Popova
SBSadek BAITI
Sadek BAITI
Gesneriaceae plant family is comprised of resurrection species, namely Boea hygrometrica and Paraboea rufescens, that are native to the Southeast Asia and Haberlea rhodopensis, Ramonda myconi, and Ramonda serbica, which are mainly found in the Balkan Peninsula. Haberlea rhodopensis is known to be able to survive extreme and prolonged dehydration. Study was carried out after the dried plant Haberlea rhodopensis Friv. had been hydrated and had reached its fresh state. Two juice samples were collected from the plant blossom: The first sample was prepared with 1% filtered water through a patented EVOdrop device. Then the sample was saturated with hydrogen with EVOdrop booster to a concentration of 1.2 ppm, pH = 7.3, ORP = −390 mV. This first sample was prepared with filtered tap water from Sofia, Bulgaria. The second sample, which was a control one, was developed with tap water from Sofia, Bulgaria, consisting of 1% solutions of Haberlea rhodopensis. A study revealed that during the drying process in H. rhodopensis the number of free water molecules decreases, and water dimers are formed. The aim of our study was to determine the number of water molecules in clusters in 1% solutions of hydrated H. rhodopensis plants. Results were analyzed according to the two types of water used in the experiment. Th EVOdrop device is equipped with an ultranano membrane and rotating jet nozzle to create a vortex water and saturation thanks to a second device EVObooster to obtain hydrogen-rich water. In the current study Hydrogen-rich water is referred to as Hydrogen EVOdrop Water (HEW). Research was conducted using the following methods—spectral methods non-equilibrium energy spectrum (NES) and differential non-equilibrium energy spectrum (DNES), mathematical models, and study of the distribution of water molecules in water clusters. In a licensed Eurotest Laboratory, the research of tap water before and after flowing through the EVOdrop device was proven. Studies have been carried out on the structuring of water molecule clusters after change of hydrogen bond energies. The restructuring comes with rearrangement of water molecules by the energy levels of hydrogen bonds. Local extrema can be observed in the spectrum with largest amount of water molecules. The structural changes were tested using the NES and DNES spectral methods. The conducted research proved that the application of EVOdrop device and EVObooster changes the parameters of water to benefit hydration and health.

4 July 2025 in Symmetry
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Ignat IgnatovIgnat Ignatov
Ignat Ignatov
YMYordan G. Marinov
Yordan G. Marinov
PVPaunka Vassileva
Paunka Vassileva
GGGeorgi Gluhchev
Georgi Gluhchev
LPLudmila Anatolievna Pesotskaya
Ludmila Anatolievna Pesotskaya
MIMario Tanev Iliev
Mario Tanev Iliev
Water’s unique physicochemical properties arise from its dynamic hydrogen-bonding network, yet the precise molecular threshold at which these cooperative behaviors emerge remains a key question. This study employed nuclear magnetic resonance (NMR) spectroscopy and density functional theory (DFT) calculations to investigate the evolution of hydrogen bonding strength in small water clusters, ranging from dimers to pentamers. The observed exponential increase in NMR chemical shift up to the pentamer reflects growing hydrogen bond cooperativity, identifying the (H2O)5 cluster as a critical structural and energetic threshold. At this size, the network achieves sufficient connectivity to support key bulk-like phenomena such as proton transfer and dielectric relaxation. These conclusions were corroborated by complementary FT-IR and electrochemical impedance spectroscopy (EIS) measurements of bulk water. Our results position the water pentamer as the molecular onset of emergent solvent behavior, effectively bridging the divide between discrete clusters and the macroscopic properties of liquid water.

13 November 2024 in Water
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NVNikolay Vassilev
Nikolay Vassilev
Ignat IgnatovIgnat Ignatov
Ignat Ignatov
TPTeodora Petrova Popova
Teodora Petrova Popova
FHFabio Hüther
Fabio Hüther
Ignat IgnatovIgnat Ignatov
Ignat Ignatov
YMYordan G. Marinov
Yordan G. Marinov
The present study investigated the 1H Nuclear Magnetic Resonance (NMR) spectra of hydrogen-rich water (HRW) produced using the EVObooster device. The analyzed HRW has pH = 7.1 ± 0.11, oxidation–reduction potential (ORP) of (−450 ± 11) mV, and a dissolved hydrogen concentration of 1.2 ppm. The control sample was tap water filtered by patented technology. A 600 NMR spectrometer was used to measure NMR spectra. Isotropic 1H nuclear magnetic shielding constants of the most stable clusters (H2O)n with n from 3 to 28 have been calculated by employing the gauge-including-atomic-orbital (GIAO) method at the MPW1PW91/6-311+G(2d,p) density function level of theory (DFT). The HRW chemical shift is downfield (higher chemical shifts) due to increased hydrogen bonding. More extensive formations were formed in HRW than in control filtered tap water. The exchange of protons between water molecules is rapid in HRW, and the 1H NMR spectra are in fast exchange mode. Therefore, we averaged the calculated chemical shifts of the investigated water clusters. As the size of the clusters increases, the number of hydrogen bonds increases, which leads to an increase in the chemical shift. The dependence is an exponential saturation that occurs at about N = 10. The modeled clusters in HRW are structurally stabilized, suggesting well-ordered hydrogen bonds. In the article, different processes are described for the transport of water molecules and clusters. These processes are with aquaporins, fusion pores, gap-junction channels, and WAT FOUR model. The exponential trend of saturation shows the dynamics of water molecules in clusters. In our research, the chemical shift of 4.257 ppm indicates stable water clusters of 4–5 water molecules. The pentagonal rings in dodecahedron cage H3O+(H2O)20 allow for an optimal arrangement of hydrogen bonds that minimizes the potential energy.

9 March 2025 in Crystals
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Ignat IgnatovIgnat Ignatov
Ignat Ignatov
YMYordan G. Marinov
Yordan G. Marinov
PVPaunka Vassileva
Paunka Vassileva
TPTeodora Petrova Popova
Teodora Petrova Popova
GGGeorgi Gluhchev
Georgi Gluhchev
IGIrina Marinova Gotova
Irina Marinova Gotova
This study explores the structural and chemical interactions between glacial water, ice Ih, and hydration clusters of divalent cations (Ca2⁺ and Mg2⁺). Ice Ih, with its hexagonal lattice and tetrahedral bonding network, is incompatible with the hydration shells of Ca2⁺ and Mg2⁺, which adopt octahedral geometries in aqueous solutions. During freezing, these hydration clusters become disordered, causing distortions in the ice structure. Slow freezing reduces these distortions, while rapid freezing traps ions in amorphous regions, preventing proper alignment of hydration clusters. Through advanced techniques such as chemical and isotopic analysis, computational modeling, and electrical impedance spectroscopy, this study examines ion exclusion mechanisms and water-clustering behaviors. The results show that both ions are largely excluded from the solid phase during freezing, with Mg2⁺ exhibiting stronger exclusion due to its smaller ionic radius and greater hydration energy. This study also highlights the role of sediments in modulating ion patterns in glacial ice. This work deepens our understanding of ion–ice interactions, offering insights for cryochemistry, hydrology, and environmental science. The integration of experimental and computational methods provides new perspectives on divalent cations’ role in modifying ice’s crystalline structure and explains isotopic variability in glacial waters.

31 January 2023 in Journal of Chemical Technology and Metallurgy
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DMDimitar Mehandjiev
Dimitar Mehandjiev
Ignat IgnatovIgnat Ignatov
Ignat Ignatov
NNNikolai Neshev
Nikolai Neshev
PVPaunka Vassileva
Paunka Vassileva
GGGeorgi Gluhchev
Georgi Gluhchev
CDChristos Drossinakis
Christos Drossinakis
An investigation of simultaneous osmosis and diffusion was conducted in a setup consisting of a cylindrical ceramic element initially filled with 0.9 % sodium chloride (NaCl) aqueous solution and immersed a beaker initially filled with deionized water. The cylindrical element was made of kaolin with chemical composition Al 2 O 3 (52 %) SiO 2 (47 %) Na 2 O (0.3 %) K 2 O (0.7 %) and pore size of 0.1-0.2 µm The levels of both liquids were the same at the start of the experiment and their ionic concentrations were monitored by measuring electrical conductivity with two identical meters with fixed probes in the corresponding sections. At a temperature of 20.4 o C, the final equilibrium occurred in 339 hours. Subsequently, the hydrogen bonds energy distributions of the two sulutions already with equal sodium chloride (NaCl) concentrations were measured with the methods of Non-equilibrium Energy Spectrum (NES) and Differential Non-equilibrium Energy Spectrum (NES). Distinct differences between the spectra were found in the whole range of (-E) from 0.0937 to 0.1387 eV, particularly at (0.1112 eV) (λ = 11.15 μm) (ṽ = 897 cm-1) eV and (0.1362 eV) (λ = 11.15 μm) (ṽ = 897 cm-1). In addition, the average strength of hydrogen bonds in the ceramic element was calculated as greater than that in the beaker.