Prospects for plasmonic hot spots in single molecule SERS towards the chemical imaging of live cells

Single molecule surface enhanced Raman scattering (SM-SERS) is a highly local effect occurring at sharp edges,} interparticle junctions and crevices or other geometries with a sharp nanoroughness of plasmonic nanostructures ({"}hot spots{"}). The emission of an individual molecule at SM-SERS conditions depends on the local enhancement field of the hot spots{,} as well as the binding affinity and positioning at a hot spot region. In this regard{,} the stability of near-field nano-optics at hot spots is critical{,} particularly in a biological milieu. In this perspective review{,} we address recent advances in the experimental and theoretical approaches for the successful development of SM-SERS. Significant progress in the understanding of the interaction between the excitation electromagnetic field and the surface plasmon modes at the metallic or metallic/dielectric interface of various curvatures are described. New knowledge on methodological strategies for positioning the analytes for SM-SERS and Raman-assisted SERS or the SERS imaging of live cells has been acquired and displayed. In the framework of the extensive development of SM-SERS as an advancing diagnostic analytical technique{,} the real-time SERS chemical imaging of intracellular compartments and tracing of individual analytes has been achieved. In this context{, we highlight the tremendous potential of SERS chemical imaging as a future prospect in SERS and SM-SERS for the prediction and diagnosis of diseases

Spectroscopic investigation of composite polymeric and monocrystalline systems with ionic conductivity

The conductivity mechanism is studied in the LiCF3SO3-doped polyethylene oxide by monitoring the vibrations of sulfate groups and mobility of Li+ ion along the polymeric chain at different EO/Li molar ratios in the temperature range from 16 to 90 °С. At the high EO/Li ratio (i.e., 30), the intensity of bands increases and a triplet appears at 1,045 cm−1, indicating the presence of free anions, ionic pairs and aggregates. The existence of free ions in the polymeric electrolyte is also proven by the red shift of bands in Raman spectra and a band shift to the low frequency Infra-red region at 65 < T < 355 °С. Based on quantum mechanical modeling, (method MNDO/d), the energies (minimum and maximum) correspond to the most probable and stable positions of Li+ along the polymeric chain. At room temperature, Li+ ion overcomes the intermediate state (minimum energy) through non-operating transitions (maximum energy) due to permanent intrapolymeric rotations (rotation of C, H and O atoms around each other). In solid electrolyte (Li2SO4) the mobility of Li+ ions increases in the temperature range from 20 to 227 °С, yielding higher conductivity. The results of the present work can be practically applied to a wide range of compact electronic devices, which are based on polymeric or solid electrolytes

Crime trends and the COVID-19

In response to the pandemic, cities implemented states of emergency and stay at home in order to reduce virus spread. Changes in social dynamics due to local restrictions impacted human behavior and led to a shift in crime dynamics. We analyze shifts in crime types by comparing crimes before the implementation of stay at home orders and the time period shortly after these orders were put in place across the world

Crime trends and the COVID-19

In response to the pandemic, cities implemented states of emergency and stay at home in order to reduce virus spread. Changes in social dynamics due to local restrictions impacted human behavior and led to a shift in crime dynamics. We analyze shifts in crime types by comparing crimes before the implementation of stay at home orders and the time period shortly after these orders were put in place across the world

Ultrasonic Formation of Fe3O4‑Reduced Graphene Oxide−Salicylic Acid Nanoparticles with Switchable Antioxidant Function

We demonstrate a single-step ultrasonic in situ complexation of salicylic acid during the growth of Fe3O4-reduced graphene oxide nanoparticles (∼10 nm) to improve the antioxidant and antiproliferative effects of pristine drug molecules. These nanoparticles have a precisely defined electronic molecular structure with salicylic acid ligands specifically complexed to Fe(III)/Fe(II) sites, four orders of magnitude larger electric surface potential, and enzymatic activity modulated by ascorbic acid molecules. The diminishing efficiency of hydroxyl radicals by Fe3O4-rGO-SA nanoparticles is tenfold higher than that by pristine salicylic acid in the electro-Fenton process. The H+ production of these nanoparticles can be switched by the interaction with ascorbic acid ligands and cause the redox deactivation of iron or enhanced antioxidation, where rGO plays an important role in enhanced charge transfer catalysis. Fe3O4-rGO-SA nanoparticles are nontoxic to erythrocytes, i.e., human peripheral blood mononuclear cells, but surpassingly inhibit the growth of three cancer cell lines, HeLa, HepG2, and HT29, with respect to pristine salicylic acid molecules

Электромагнитная активизация салициловой кислоты в комплексе с оксидированной цинк-графеновой структурой

This work aims at the development of a method of electromagnetic activation of salicylic acid molecules per se (SA) through the ultrasonic (20 kHz) complexation with oxidized zinc-graphene structure. The result of this work implies synthesized nanopartiсles “ZnO – partially restored graphene oxide (rGO) – SA” with the average size of (5.53 ± 0.11) nm and hexagonal wurtzite zinc oxide structure with complexed SA molecules. Complexation of SA with “ZnO – rGO” matrix causes magnification of electromagnetic field of SA by 102 times with the local enhancement at the contact with ZnO by 103 times, and therefore allowing selective electromagnetic activation of drug molecules. The developed method of “ZnO – rGO – SA” nanoparticles formation can be applied to many different drugs and drug-based devices, thereby introducing a great interest in medicinal electronics and nanomedicine.  Представлен метод электромагнитной активизации молекул салициловой кислоты per se (СК) посредством ультразвукового (20 кГц) комплексообразования с оксидированной цинк-графеновой структурой. Результатом разработки явились сформированные наночастицы «ZnO – частично восстановленный кислородсодержащий графен (кГ) – СК» со средним размером (5,53 ± 0,11) нм и гексагональной сингонией типа вюрцита оксида цинка с комплексами молекул салициловой кислоты. Комплексообразование салициловой кислоты с матрицей «ZnO – кГ» приводит к усилению электромагнитного поля салициловой кислоты в 102 раза с локальным увеличением при контакте с ZnO в 103 раза и, как следствие, к избирательной электромагнитной активизации молекул лекарственного вещества. Разработанный метод формирования наночастиц с составом «ZnO – кГ – СК» можно применить ко многим другим лекарственным соединениям и устройствам на их основе, что представляет большой интерес для медицинской электроники и наномедицины.

Potent E. coli M‑17 Growth Inhibition by Ultrasonically Complexed Acetylsalicylic Acid−ZnO−Graphene Oxide Nanoparticles

A single-step ultrasonic method (20 kHz) is demonstrated for the complexation of acetylsalicylic acid (ASA)−ZnO− graphene oxide (GO) nanoparticles with an average size of <70 nm in aqueous solution. ASA−ZnO−GO more e ffi ciently inhibits the growth of probiotic Escherichia coli strain M-17 and exhibits enhanced antioxidant properties than free ASA and ASA−ZnO in neutralization of hydroxyl radicals in the electro-Fenton process. This improved function of ASA in the ASA −ZnO GO can be attributed to the well-de fi ned cone-shaped morphology, the surface structure containing hydroxyl and carboxylate groups of ZnO−GO nanoparticles, which facilitated the complexation with ASA

Vertically oriented graphene based walls and columns obtained by ICP CVD method on moving substrates as prior stage of the roll-to-roll technology

Superior optoelectronic properties of graphene have made this material as a special applicant in displays, touch and graphene-based screens with smaller and long-lasting batteries including the field of mobile telephony. Recently we have introduced the process for the formation of vertically oriented graphene (VOG) walls with a curved morphology by ICP CVD method. Such VOG walls represent a very promising material for different applications (e.g. miniature batteries and other optoelectronic devices) due to its unique orientation and open carbon network structure. For the first time such VOG walls have been grown directly on a moving substrate that is a prerequisite for its production by the roll-to-roll technology providing higher yield of the production process at lower cost of the product

Воздействие ультразвука на нестероидные противовоспалительные лекарства в комплексных соединениях нанокомпозитов на основе оскидов меди, железа, цинка и графена

This work aims at the formation of nanocomposites based on graphene and metal oxides (copper-iron, zinc and iron) through ultrasonic interaction (20 kHz) and investigation of their electromagnetic properties by scanning electron microscopy, Raman and absorption spectroscopy, and fluorescence methods. The output of this work implies the development of a single-step ultrasound method to form functional Cu/Fe-, ZnO-and Fe3O4-polyvinyl alcohol nanocomposites, and the ultrasonic conjugation of these nanocomposites with pristine drugs, such as ketorolac and acetylsalicylic acid. We established that formed Cu/Fe-graphene-ketorolac, ZnO-grapheneacetylsalicylic acid and Fe3O4-ketorolac obtain optical and superparamagnetic properties of nanoparticles with improved electromagnetic characteristics due to ultrasonic conjugation. Cu/Fe-graphene-ketorolac nanocomposites are revealed to have a spherical shape (&lt; 100 nm) and acquire improved optoelectronic properties due to copper and iron atoms in the matrix of graphene. It is demonstrated that ZnO-graphene-acetylsalicylic acid nanocomposites obtain properties of fluorescence mainly for electromagnetic interaction with the ZnO phase formed on the surface of graphene. Ultrasonic conjugation of ketorolac with magnetite proved to increase the electron density of Fe3O4-ketorolac that obtains superparamagnetic properties, and its biocompatibility can be improved when coated with polyvinyl alcohol. In general, formed nanocomposites are of great interest in medical electronics and nanomedicine as functional materials with electromagnetic properties being controlled at the molecular and atomic levels. Such nanocomposites can also find application as components in electronic devices for diagnosis and treatment of serious inflammatory disorders. Industries will find the singlestep ultrasound method of special interest because it is eco-friendly and can be scaled up by a versatile spectrum of inorganic and organic materials and drugs.Целью работы является формирование нанокомпозитов на основе оксидированного графена и оксидов металлов (медь-железо, цинк и железо) посредством взаимодействия с ультразвуком (20 кГц) и исследование их электромагнитных свойств с помощью методов сканирующей электронной микроскопии, спектроскопии комбинационного рассеяния света, поглощения электромагнитного излучения и флуоресценции. Результатом работы является разработка одношагового метода ультразвука для формирования функциональных нанокомпозитов Cu/Fe-, ZnO- и Fe3O4-поливиниловый спирт и метода ультразвукового коньюгирования исходных лекарственных соединений, таких как кеторолак и ацетилсалициловая кислота, с данными нанокомпозитами. Установлено, что сформированные лекарственные нанокомпозиты Cu/Fe-графен-кеторолак, ZnO-графен-ацетилсалициловая кислота и Fe3O4-кеторолак приобретают оптические и суперпарамагнитные свойства наночастиц с улучшенными электромагнитными характеристиками благодаря ультразвуковой коньюгации. Выявлено, что нанокомпозиты Cu/Fe-графен-кеторолак имеют сферическую форму и размер, не превышающий 100 нм, на поверхности послойной структуры оксидированного графена. Сформированные нанокомпозиты Cu/Fe-графен-кеторолак приобретают улучшенные оптоэлектронные свойства благодаря наличию атомов меди и железа в матрице графена. Показано, что нанокомпозиты ZnO-графен-ацетилсалициловая кислота приобретают улучшенные свойства флуоресценции преимущественно за счет электромагнитного взаимодействия с фазой оксида цинка, сформированной на поверхности графена. Доказано, что коньюгирование кеторолака с магнетитом увеличивает электронную плотность нанокомпозита Fe3O4-кеторолак, который приобретает суперпарамагнитные свойства, а его покрытие поливиниловым спиртом может улучшить биосовместимость. В целом сформированные нанокомпозиты представляют большой интерес в области медицинской электроники и наномедицины в качестве функциональных материалов с улучшенными электромагнитными свойствами, контролируемыми на молекулярном и атомном уровне. Данные нанокомпозиты могут найти применение как в качестве материалов, так и компонентов в электронных устройствах для диагностики и лечения воспалительных заболеваний. Для промышленной области особый интерес представляет одношаговый экологически чистый метод ультразвука, применение которого можно расширить разнообразным спектром неорганических и органических материалов и лекарственных веществ