Nadezhda Besedina - Academia.edu (original) (raw)
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Papers by Nadezhda Besedina
The paper presents a new study of correlation between morphology of thin carbon films deposited o... more The paper presents a new study of correlation between morphology of thin carbon films deposited on Si substrates, their electronic properties and capability of cold electron emission in electric field with macroscopic magnitude of the order of 1 V/μm. Comparative experiments have demonstrated that substrate parameters have little, if any, direct effect on emission properties of the films: the observed variations of the emission threshold field value in the range from several percent up to two times depending on the substrate species was attributed to substrate-orientation-sensitive mechanism of the film growth leading to notable difference in topography of the compared films (indirect effect). Tunneling spectroscopy study showed that the films with the best emission properties comprise sp2 carbon islands (or carbon dots, CDs) having electron systems separated from each other and from the substrate. This conclusion has been supported by the presence of a photoluminescence component i...
Derivatization of 2D materials for bioapplications is at the forefront of nanomaterials research ... more Derivatization of 2D materials for bioapplications is at the forefront of nanomaterials research nowadays. Facile synthesis of the biografted 2D derivatives and insight into the conformation of the conjugated biomolecules are two pillars, promoting advances in the field of biosensing, drug delivery and regeneration techniques. This work is devoted to the synthesis and conjugation of carboxylated graphene by aptamers followed by theoretical analysis of their conformation in the immobilized state. Employing the developed method, the hole-matrixed graphene with up to 11.1 at.% reactive carboxyl groups was synthesized and thoroughly examined via core-level spectroscopy and time-resolved methods. The mechanism of the performed carboxylation with conversion of graphene oxide into carboxylated graphene is proposed, unveiling commonly disregarded impact of ether-like components to the fingerprints of the carboxyl groups. We show successful covalent immobilization of the AO-01 aptamer agains...
Materials Science and Engineering: C
Fullerenes, Nanotubes and Carbon Nanostructures
In the present paper, a new approach for detonation nanodiamond (DND) deagglomeration is proposed... more In the present paper, a new approach for detonation nanodiamond (DND) deagglomeration is proposed. DND agglomerates of the size from 20 to 200 nm have been exposed to wet sonication assisted oxidat...
Scientific Reports
In this paper we present a facile method for the synthesis of aminated graphene derivative throug... more In this paper we present a facile method for the synthesis of aminated graphene derivative through simultaneous reduction and amination of graphene oxide via two-step liquid phase treatment with hydrobromic acid and ammonia solution in mild conditions. The amination degree of the obtained aminated reduced graphene oxide is of about 4 at.%, whereas C/O ratio is up to 8.8 as determined by means of X-ray photoelectron spectroscopy. The chemical reactivity of the introduced amine groups is further verified by successful test covalent bonding of the obtained aminated graphene with 3-Chlorobenzoyl chloride. The morphological features and electronic properties, namely conductivity, valence band structure and work function are studied as well, illustrating the influence of amine groups on graphene structure and physical properties. Particularly, the increase of the electrical conductivity, reduction of the work function value and tendency to form wrinkled and corrugated graphene layers are ...
Fullerenes, Nanotubes and Carbon Nanostructures
Abstract The one-step method for graphene oxide (GO) simultaneous reduction and carboxylation via... more Abstract The one-step method for graphene oxide (GO) simultaneous reduction and carboxylation via ultraviolet irradiation in the inert atmosphere has been reported. X-ray photoelectron spectroscopy (XPS) and X-ray absorption spectroscopy (XAS) data revealed that the proposed approach allows to obtain reduced graphene oxide (rGO) films, containing up to 10 at.% of carboxyl groups. The carboxyl groups concentration can be tuned within the range of 3 to 10 at.% by controlling the oxidation degree of the irradiated GO via the preliminary low-temperature air heating. Furthermore, no carboxylation effect is observed in the case of irradiation of the completely reduced GO films. This coincides with our previous results, validating the proposed model of GO carboxylation based on photoinduced conversion of basal-plane hydroxyl groups and ketones into carboxyl ones. Despite a different degree of carboxylation, all the obtained samples demonstrate almost complete elimination of basal plane groups and restoration of the graphene flakes aromatic structure. This fact is emphasized by the sheet resistance measurements, demonstrating that the obtained C-xy graphene exhibits high electrical conductivity. As a net result, the material obtained by the presented method shows promising applications in the manufacturing of biosensor transducers owing to both its conductive nature and presence of carboxyl groups, playing the role of the anchoring points for biomolecules.
Cells
Microcirculation is one of the basic functional processes where the main gas exchange between red... more Microcirculation is one of the basic functional processes where the main gas exchange between red blood cells (RBCs) and surrounding tissues occurs. It is greatly influenced by the shape and deformability of RBCs, which can be affected by oxidative stress induced by different drugs and diseases leading to anemia. Here we investigated how in vitro microfluidic characterization of RBCs transit velocity in microcapillaries can indicate cells damage and its correlation with clinical hematological analysis. For this purpose, we compared an SU-8 mold with an Si-etched mold for fabrication of PDMS microfluidic devices and quantitatively figured out that oxidative stress induced by tert-Butyl hydroperoxide splits all RBCs into two subpopulations of normal and slow cells according to their transit velocity. Obtained results agree with the hematological analysis showing that such changes in RBCs velocities are due to violations of shape, volume, and increased heterogeneity of the cells. These...
Scientific Reports
This paper reports a facile and green method for conversion of graphene oxide (GO) into graphene ... more This paper reports a facile and green method for conversion of graphene oxide (GO) into graphene by low-temperature heating (80 °C) in the presence of a glass wafer. Compared to conventional GO chemical reduction methods, the presented approach is easy-scalable, operationally simple, and based on the use of a non-toxic recyclable deoxygenation agent. The efficiency of the proposed method is further expanded by the fact that it can be applied for reducing both GO suspensions and large-scale thin films formed on various substrates prior to the reduction process. The quality of the obtained reduced graphene oxide (rGO) strongly depends on the type of the used glass wafer, and, particularly, magnesium silicate glass can provide rGO with the C/O ratio of 7.4 and conductivity of up to 33000 S*cm −1. Based on the data obtained, we have suggested a mechanism of the observed reduction process in terms of the hydrolysis of the glass wafer with subsequent interaction of the leached alkali and alkali earth cations and silicate anions with graphene oxide, resulting in elimination of the oxygencontaining groups from the latter one. The proposed approach can be efficiently used for low-cost bulkquantity production of graphene and graphene-based materials for a wide field of applications. Graphene continues to inspire interest in various fields of science due to its outstanding physical and chemical properties 1-3 , even though intensive studies devoted to this unique nanocarbon material 4,5 have been carried out during the last ten years. It seems to have a wide field of applications in different technologies, including fabrication of transparent electrodes, supercapasitors and nanoelectronic devices, gas sensing and catalysis, biochemistry and microbiology 6-9. However, the preparation of graphene in large scales remains to be a challenging task. Several strategies have been developed to overcome this challenge, such as epitaxial growth of graphene on silicon carbide (SiC) 10 , growth of graphene on the surface of transition metals by chemical vapor deposition (CVD) 11 , and reduction of graphene oxide (GO) 12. Among these methods, the reduction proved to be an effective approach to produce graphene with an optimal quality at relatively low cost 13,14. Numerous approaches are applied to achieve conversion of graphene oxide to graphene, for instance, high-temperature annealing in a reducing enviroment 15 , ultraviolet 16 and laser 17 irradiation of GO films, electrochemical 18 and chemical 19 treatment of graphene oxide suspensions and films. Compared to other techniques, the chemical reduction of GO offers great ease of large-scale production of rGO in various forms such as suspensions, rGO paper or thin films on various substrates. Various chemicals, namely, hydrazine monohydrate 20 , dimetilhydrazine 21 , hydroquinone 22 or sodium borohydride 23 are typically employed in chemical reduction of GO. However, these reducing agents are highly toxic, unrecyclable, highly unstable, or generate hazardous by-products. Moreover, strong acidic or alkaline conditions are commonly required in these reduction processes thus limiting their applicability for preparing graphene-containing polymer composites 24 when the reduction process must be carried out simultaneously with introducing graphene into the polymer matrix.
The paper presents a new study of correlation between morphology of thin carbon films deposited o... more The paper presents a new study of correlation between morphology of thin carbon films deposited on Si substrates, their electronic properties and capability of cold electron emission in electric field with macroscopic magnitude of the order of 1 V/μm. Comparative experiments have demonstrated that substrate parameters have little, if any, direct effect on emission properties of the films: the observed variations of the emission threshold field value in the range from several percent up to two times depending on the substrate species was attributed to substrate-orientation-sensitive mechanism of the film growth leading to notable difference in topography of the compared films (indirect effect). Tunneling spectroscopy study showed that the films with the best emission properties comprise sp2 carbon islands (or carbon dots, CDs) having electron systems separated from each other and from the substrate. This conclusion has been supported by the presence of a photoluminescence component i...
Derivatization of 2D materials for bioapplications is at the forefront of nanomaterials research ... more Derivatization of 2D materials for bioapplications is at the forefront of nanomaterials research nowadays. Facile synthesis of the biografted 2D derivatives and insight into the conformation of the conjugated biomolecules are two pillars, promoting advances in the field of biosensing, drug delivery and regeneration techniques. This work is devoted to the synthesis and conjugation of carboxylated graphene by aptamers followed by theoretical analysis of their conformation in the immobilized state. Employing the developed method, the hole-matrixed graphene with up to 11.1 at.% reactive carboxyl groups was synthesized and thoroughly examined via core-level spectroscopy and time-resolved methods. The mechanism of the performed carboxylation with conversion of graphene oxide into carboxylated graphene is proposed, unveiling commonly disregarded impact of ether-like components to the fingerprints of the carboxyl groups. We show successful covalent immobilization of the AO-01 aptamer agains...
Materials Science and Engineering: C
Fullerenes, Nanotubes and Carbon Nanostructures
In the present paper, a new approach for detonation nanodiamond (DND) deagglomeration is proposed... more In the present paper, a new approach for detonation nanodiamond (DND) deagglomeration is proposed. DND agglomerates of the size from 20 to 200 nm have been exposed to wet sonication assisted oxidat...
Scientific Reports
In this paper we present a facile method for the synthesis of aminated graphene derivative throug... more In this paper we present a facile method for the synthesis of aminated graphene derivative through simultaneous reduction and amination of graphene oxide via two-step liquid phase treatment with hydrobromic acid and ammonia solution in mild conditions. The amination degree of the obtained aminated reduced graphene oxide is of about 4 at.%, whereas C/O ratio is up to 8.8 as determined by means of X-ray photoelectron spectroscopy. The chemical reactivity of the introduced amine groups is further verified by successful test covalent bonding of the obtained aminated graphene with 3-Chlorobenzoyl chloride. The morphological features and electronic properties, namely conductivity, valence band structure and work function are studied as well, illustrating the influence of amine groups on graphene structure and physical properties. Particularly, the increase of the electrical conductivity, reduction of the work function value and tendency to form wrinkled and corrugated graphene layers are ...
Fullerenes, Nanotubes and Carbon Nanostructures
Abstract The one-step method for graphene oxide (GO) simultaneous reduction and carboxylation via... more Abstract The one-step method for graphene oxide (GO) simultaneous reduction and carboxylation via ultraviolet irradiation in the inert atmosphere has been reported. X-ray photoelectron spectroscopy (XPS) and X-ray absorption spectroscopy (XAS) data revealed that the proposed approach allows to obtain reduced graphene oxide (rGO) films, containing up to 10 at.% of carboxyl groups. The carboxyl groups concentration can be tuned within the range of 3 to 10 at.% by controlling the oxidation degree of the irradiated GO via the preliminary low-temperature air heating. Furthermore, no carboxylation effect is observed in the case of irradiation of the completely reduced GO films. This coincides with our previous results, validating the proposed model of GO carboxylation based on photoinduced conversion of basal-plane hydroxyl groups and ketones into carboxyl ones. Despite a different degree of carboxylation, all the obtained samples demonstrate almost complete elimination of basal plane groups and restoration of the graphene flakes aromatic structure. This fact is emphasized by the sheet resistance measurements, demonstrating that the obtained C-xy graphene exhibits high electrical conductivity. As a net result, the material obtained by the presented method shows promising applications in the manufacturing of biosensor transducers owing to both its conductive nature and presence of carboxyl groups, playing the role of the anchoring points for biomolecules.
Cells
Microcirculation is one of the basic functional processes where the main gas exchange between red... more Microcirculation is one of the basic functional processes where the main gas exchange between red blood cells (RBCs) and surrounding tissues occurs. It is greatly influenced by the shape and deformability of RBCs, which can be affected by oxidative stress induced by different drugs and diseases leading to anemia. Here we investigated how in vitro microfluidic characterization of RBCs transit velocity in microcapillaries can indicate cells damage and its correlation with clinical hematological analysis. For this purpose, we compared an SU-8 mold with an Si-etched mold for fabrication of PDMS microfluidic devices and quantitatively figured out that oxidative stress induced by tert-Butyl hydroperoxide splits all RBCs into two subpopulations of normal and slow cells according to their transit velocity. Obtained results agree with the hematological analysis showing that such changes in RBCs velocities are due to violations of shape, volume, and increased heterogeneity of the cells. These...
Scientific Reports
This paper reports a facile and green method for conversion of graphene oxide (GO) into graphene ... more This paper reports a facile and green method for conversion of graphene oxide (GO) into graphene by low-temperature heating (80 °C) in the presence of a glass wafer. Compared to conventional GO chemical reduction methods, the presented approach is easy-scalable, operationally simple, and based on the use of a non-toxic recyclable deoxygenation agent. The efficiency of the proposed method is further expanded by the fact that it can be applied for reducing both GO suspensions and large-scale thin films formed on various substrates prior to the reduction process. The quality of the obtained reduced graphene oxide (rGO) strongly depends on the type of the used glass wafer, and, particularly, magnesium silicate glass can provide rGO with the C/O ratio of 7.4 and conductivity of up to 33000 S*cm −1. Based on the data obtained, we have suggested a mechanism of the observed reduction process in terms of the hydrolysis of the glass wafer with subsequent interaction of the leached alkali and alkali earth cations and silicate anions with graphene oxide, resulting in elimination of the oxygencontaining groups from the latter one. The proposed approach can be efficiently used for low-cost bulkquantity production of graphene and graphene-based materials for a wide field of applications. Graphene continues to inspire interest in various fields of science due to its outstanding physical and chemical properties 1-3 , even though intensive studies devoted to this unique nanocarbon material 4,5 have been carried out during the last ten years. It seems to have a wide field of applications in different technologies, including fabrication of transparent electrodes, supercapasitors and nanoelectronic devices, gas sensing and catalysis, biochemistry and microbiology 6-9. However, the preparation of graphene in large scales remains to be a challenging task. Several strategies have been developed to overcome this challenge, such as epitaxial growth of graphene on silicon carbide (SiC) 10 , growth of graphene on the surface of transition metals by chemical vapor deposition (CVD) 11 , and reduction of graphene oxide (GO) 12. Among these methods, the reduction proved to be an effective approach to produce graphene with an optimal quality at relatively low cost 13,14. Numerous approaches are applied to achieve conversion of graphene oxide to graphene, for instance, high-temperature annealing in a reducing enviroment 15 , ultraviolet 16 and laser 17 irradiation of GO films, electrochemical 18 and chemical 19 treatment of graphene oxide suspensions and films. Compared to other techniques, the chemical reduction of GO offers great ease of large-scale production of rGO in various forms such as suspensions, rGO paper or thin films on various substrates. Various chemicals, namely, hydrazine monohydrate 20 , dimetilhydrazine 21 , hydroquinone 22 or sodium borohydride 23 are typically employed in chemical reduction of GO. However, these reducing agents are highly toxic, unrecyclable, highly unstable, or generate hazardous by-products. Moreover, strong acidic or alkaline conditions are commonly required in these reduction processes thus limiting their applicability for preparing graphene-containing polymer composites 24 when the reduction process must be carried out simultaneously with introducing graphene into the polymer matrix.