From graphene oxide towards aminated graphene facile synthesis, its structure and electronic properties

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 observed in the aminated graphene derivative compared to the pristine reduced graphene oxide. As obtained aminated graphene could be used for photovoltaic, biosensing and catalysis application as well as a starting material for further chemical modifications

Pathogenetic mechanisms of destructive pneumonia in children. Case report with literature review

E.M. Tolstova1, M.V. Besedina1, O.V. Zaytseva1, N.S. Zaitseva1, S.B. Yatsyshina2, D.V. Khaspekov3, E.B. Olkhova1,3, I.V. Turishchev3, N.A. Sholokhova3,4, P.P. Galeev3, T.Yu. Belyaeva3 1A.I. Yevdokimov Moscow State University of Medicine and Dentistry, Moscow, Russian Federation 2Central Research Institute of Epidemiology of the Russian Federal Service for Supervision of Consumer Rights Protection and Human Well-Being, Moscow, Russian Federation 3St. Vladimir Children's City Clinical Hospital, Moscow, Russian Federation 4Russian Medical Academy of Continuous Professional Education, Moscow, Russian Federation Destructive pneumonia (DP) in children is a complication derived from community-acquired pneumonia, while parenchymal necrosis occurs in the pulmonary infiltration zone with the formation of multiple merging small cavities. The disease pathogenesis has not yet been precisely established. The factors predisposing to pulmonary destructive complications in pneumonia remain unknown. We present a case study of this disease in a 5-year-old female patient hospitalized in December 2022. Manifestation in the form of acute upper respiratory tract infection, subsequent deterioration with the progression of pneumonia and pleurisy indicate the importance of viral-bacterial interactions in the DP pathogenesis. Influenza A was confirmed in the laboratory, while Streptococcus pneumoniae was isolated in the fluid culture obtained during bronchoalveolar lavage. Using the example of the presented case, we discuss the mechanisms of DP pathogenesis in children from a modern perspective. The necessity of coagulology, a combination of radiology diagnostic methods (radiography, ultrasound, computed tomography) was justified. It is necessary to further study the pathogenetic mechanisms of the DP progression in order to optimize preventive and therapeutic rehabilitation measures in community-acquired pneumonia in children. Keywords: destructive pneumonia, necrotizing pneumonia, influenza A, Streptococcus pneumoniae, hypercoagulation. For citation: Tolstova E.M., Besedina M.V., Zaytseva O.V., Zaitseva N.S., Yatsyshina S.B., Khaspekov D.V., Olkhova E.B., Turishchev I.V., Sholokhova N.A., Galeev P.P., Belyaeva T.Yu. Pathogenetic mechanisms of destructive pneumonia in children. Case report with literature review. Russian Journal of Woman and Child Health. 2023;6(3):310–319 (in Russ.). DOI: 10.32364/2618-8430-2023-6-3-15. </p

Graphene Amination towards Its Grafting by Antibodies for Biosensing Applications

The facile synthesis of biografted 2D derivatives complemented by a nuanced understanding of their properties are keystones for advancements in biosensing technologies. Herein, we thoroughly examine the feasibility of aminated graphene as a platform for the covalent conjugation of monoclonal antibodies towards human IgG immunoglobulins. Applying core level spectroscopy methods, namely X ray photoelectron and absorption spectroscopies, we delve into the chemistry and its effect on the electronic structure of the aminated graphene prior to and after the immobilization of monoclonal antibodies. Furthermore, the alterations in the morphology of the graphene layers upon the applied derivatization protocols are assessed by electron microscopy techniques. Chemiresistive biosensors composed of the aerosol deposited layers of the aminated graphene with the conjugated antibodies are fabricated and tested, demonstrating a selective response towards IgM immunoglobulins with a limit of detection as low as 10 pg mL. Taken together, these findings advance and outline graphene derivatives application in biosensing as well as hint at the features of the alterations of graphene morphology and physics upon its functionalization and further covalent grafting by biomolecule

Guiding graphene derivatization for covalent immobilization of aptamers

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 reduced graphene oxide C xyrGO 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. 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 against Hepatitis B protein on the synthesized C xyrGO and for the first time reveal its conformation both in free and immobilized forms via a combination of density functional tight binding DFTB calculations and molecular dynamic MD modeling. Taken together, these results advance the application of graphene derivatives grafted with the biomolecules in the field of biosensin