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1.
Synthesis of nanomaterials is an emerging field due to their fascinating properties for applications in different field and green synthesis offers various advantages versus physical and chemical methods. Herein, green protocol has been adopted for the synthesis of silver nanoparticles (Ag NPs) using seeds extract of strawberry. The Ag NPs were characterized using advanced techniques comprising UV/Vis, XRD, FTIR, SEM, DLS and EDX. The λ max for the Ag NPs was recorded at 405 nm. The functional groups present in the extract and involved in Ag ions reduction were determined using FTIR analysis. The SEM-EDX analysis confirmed the mono-dispersive nature of Ag NPs along with confirmation of elemental composition. The nanoparticles size distribution was recorded in 50-70 nm range. Bio-fabricated Ag NPs were appraised for antioxidant activity (DPPH with % inhibition 56.61 and ABTS with % inhibition 77.81) and antimicrobial activity, i.e., Escherichia coli, Salmonella typhimurium, Shigella sonnei, Halomonas halophile, Staphylococcus aureus and Bacillus subtilis. It is concluded that these synthesized NPs could probably be applied as potent antibacterial and antioxidant materials. 相似文献
2.
The development of green and convenient methods for C–S bond formation has received significant attention because C–S bond widely occurs in many important pharmaceutical and biological compounds.Recently, visible-light photoredox catalysis has been established as an efficient and general tool for the construction of C–C and C-heteroatom bonds. In this review, we have focused on the research on recent advances in C–S bond formation via visible-light photoredox catalysis, and the growing opportuni... 相似文献
4.
Allenes are valuable organic molecules that feature unique physical and chemical properties. They are not only often found in natural products, but also act as versatile building blocks for the access of complex molecular targets, such as natural products, pharmaceuticals, and functional materials. Therefore, many remarkable and elegant methodologies have been established for the synthesis of allenes. Recently, more and more methods for radical synthesis of allenes have been developed, clearly emphasizing the associated great synthetic values. In this perspective, we will discuss recent important advances in the synthesis of allenes via radical intermediates by categorizing them into different types of substrates as well as distinct catalytic systems. The mechanistic studies and synthetic challenges will be highlighted.Recent important advances in the synthesis of allenes via radical strategies are highlighted. 相似文献
5.
Fluorescent nanoparticles (NPs), including semiconductor NPs (Quantum Dots), metal NPs, silica NPs, polymer NPs, etc., have been a major focus of research and development during the past decade. The fluorescent nanoparticles show unique chemical and optical properties, such as brighter fluorescence, higher photostability and higher biocompatibility, compared to classical fluorescent organic dyes. Moreover, the nanoparticles can also act as multivalent scaffolds for the realization of supramolecular assemblies, since their high surface to volume ratio allow distinct spatial domains to be functionalized, which can provide a versatile synthetic platform for the implementation of different sensing schemes. Their excellent properties make them one of the most useful tools that chemistry has supplied to biomedical research, enabling the intracellular monitoring of many different species for medical and biological purposes. In this review, we focus on the developments and analytical applications of fluorescent nanoparticles in chemical and biological sensing within the intracellular environment. The review also points out the great potential of fluorescent NPs for fluorescence lifetime imaging microscopy (FLIM). Finally, we also give an overview of the current methods for delivering of fluorescent NPs into cells, where critically examine the benefits and liabilities of each strategy. 相似文献
6.
The chemical class of benzopyrones consists of a large number of compounds possessing the benzene ring fused with the oxygen containing pyrone ring. This class is further divided into the benzo-γ-pyrone i.e. flavonoids and the benzo-α-pyrone i.e. coumarins. Coumarins, the 2 H-chromen-2-one and its related analogues exhibit a multitude of biological activities. Attempts made in the continuous chemical diversification of this parent nucleus have brought significant alterations in the biological activity among the generated compounds and therefore, this category of benzopyrones has been much exploited in the current medicinal chemistry research. Thus, it was thought worthwhile to present a review on the newly synthesised heterocyclic coumarinyl derivatives with their physicochemical parameters and biological activity, attempted by our co-workers. This review also creates a platform for highlighting approaches and strategies used in the chemical synthesis of coumarinyl compounds along with their biological activity relating to their structure. 相似文献
7.
Silicon nanoparticles (NPs) serve a wide range of optical, electronic, and biological applications. Chemical grafting of various molecules to Si NPs can help to passivate their reactive surfaces, “fine‐tune” their properties, or even give them further interesting features. In this work, 1H, 13C, and 29Si solid‐state NMR spectroscopy has been combined with density functional theory calculations to study the surface chemistry of hydride‐terminated and alkyl‐functionalized Si NPs. This combination of techniques yields assignments for the observed chemical shifts, including the contributions resulting from different surface planes, and highlights the presence of physisorbed water. Resonances from near‐surface 13C nuclei were shown to be substantially broadened due to surface disorder and it is demonstrated that in an ambient environment hydride‐terminated Si NPs undergo fast back‐bond oxidation, whereas long‐chain alkyl‐functionalized Si NPs undergo slow oxidation. Furthermore, the combination of NMR spectroscopy and DFT calculations showed that the employed hydrosilylation reaction involves anti‐Markovnikov addition of the 1‐alkene to the surface of the Si NPs. 相似文献
8.
Ternary composites of reduced graphene oxide (GR)-CdS-Pd have been successfully synthesized via solvothermal and photodeposition methods for photocatalytic selective conversion of benzyl alcohol (BA) coupled with hydrogen (H 2) production, which exhibit significantly improved photoactivity and selectivity than bare CdS. Mechanistic studies unveil that the cooperative effect of the close interface contact and matched energy level alignment between electrical conducting GR nanosheets (NSs) and CdS nanoparticles (NPs) in GR-CdS-Pd composite not only benefits the separation and transfer of photogenerated carriers but also improves the photocorrosion resistance of CdS. The photodeposited Pd NPs further promote the photogenerated charge separation and accelerate the formation of intermediate products ( α-hydroxybenzyl radicals), thereby contributing to enhanced conversion of BA. This work would facilitate the rational design of GR as cocatalyst to construct an efficient and stable CdS-based composite photocatalyst for cooperative coupling of fine chemical synthesis and H 2 evolution. 相似文献
9.
Understanding interactions between nanoparticles (NPs) with biological matter, particularly cells, is becoming increasingly important due to their growing application in medicine and materials, and consequent biological and environmental exposure. For NPs to be utilised to their full potential, it is important to correlate their functional characteristics with their physical properties, which may also be used to predict any adverse cellular responses. A key mechanism for NPs to impart toxicity is to gain cellular entry directly. Many parameters affect the behaviour of nanomaterials in a cellular environment particularly their interactions with cell membranes, including their size, shape and surface chemistry as well as factors such as the cell type, location and external environment (e.g. other surrounding materials, temperature, pH and pressure). Aside from in vitro and in vivo experiments, model cell membrane systems have been used in both computer simulations and physicochemical experiments to elucidate the mechanisms for NP cellular entry. Here we present a brief overview of the effects of NPs physical parameters on their cellular uptake, with focuses on 1) related research using model membrane systems and physicochemical methodologies; and 2) proposed physical mechanisms for NP cellular entrance, with implications to their nanotoxicity. We conclude with a suggestion that the energetic process of NP cellular entry can be evaluated by studying the effects of NPs on lipid mesophase transitions, as the molecular deformations and thus the elastic energy cost are analogous between such transitions and endocytosis. This presents an opportunity for contributions to understanding nanotoxicity from a physicochemical perspective. 相似文献
10.
Organomagnesium compounds, represented by the Grignard reagents, are one of the most classical yet versatile carbanion species which have widely been utilized in synthetic chemistry. These reagents are typically prepared via oxidative addition of organic halides to magnesium metals, via halogen–magnesium exchange between halo(hetero)arenes and organomagnesium reagents or via deprotonative magnesiation of prefunctionalized (hetero)arenes. On the other hand, recent studies have demonstrated that the organo-alkaline earth metal complexes including those based on heavier alkaline earth metals such as calcium, strontium and barium could be generated from readily available non-polar unsaturated molecules such as alkenes, alkynes, 1,3-enynes and arenes through unique metallation processes. Nonetheless, the resulting organo-alkaline earth metal complexes could be further functionalized with a variety of electrophiles in various reaction modes. In particular, organocalcium, strontium and barium species have shown unprecedented reactivity in the downstream functionalization, which could not be observed in the reactivity of organomagnesium complexes. This perspective will focus on the newly emerging protocols for the generation of organo-alkaline earth metal complexes from non-polar unsaturated molecules and their applications in chemical synthesis and catalysis.In this perspective, we highlight the recent development of metallation protocols of non-polar unsaturated molecules for the generation of organo-alkaline earth metal compounds and their applications in chemical synthesis and catalysis. 相似文献
11.
The soft chemistry method has been used to synthesize γ-Fe 2O 3 nanoparticles: various synthesis temperature were applied to obtain nanometric powders with crystallite size in the 9-14 nm range. Powders were characterized by X-ray diffraction (XRD), Fourier transform infrared (FT-IR) spectrophotometry, surface area measurements, and electron microscopy (TEM, SEM). It is clearly shown that these nanometric powders are very well crystallized as indicated by XRD and IR spectra which present substructural bands attributed to vacancies ordering ( P4 132). Based on these model materials and in the crystallite size range studied here, cell parameter appears to be not linked to crystallite size. It rather depends both on hydroxide adsorption and chemical composition. 相似文献
12.
Membrane filtration is one of the effective approaches to harvest microalgae for industrial biofuel production. However, during the filtration process, microalgae cells and extracellular organic matter (EOM) will deposit on the membrane surface leading to reversible membrane fouling that can be removed by physical methods. When hydrophobic EOM is adsorbed on the membrane surface or inside pores, it will build up a gel layer, causing irreversible membrane fouling. Irreversible fouling can only be removed using chemical methods that will decrease membrane lifespan and increase operational costs. Here, we introduce a versatile superhydrophilic membrane with photo-Fenton self-cleaning property, which can prevent the reversible fouling and remove the irreversible fouling. Tannic acid (TA) and 3-aminopropyltriethoxysilane (APTES) were co-deposited on the polyvinylidene fluoride (PVDF) membrane via Schiff base and Michael addition reactions, and β-FeOOH nanorods were inlaid on the membrane surface by in situ mineralization. The water contact angle of the modified membrane is reduced from 120° to 0° Under 60 min visible light, the hydroxyl radical ( ·OH) generated by the photo-Fenton reaction degraded the irreversible fouling that blocked membrane pores. The irreversible fouling rates of modified membrane was reduced from 39.57% to 3.26%, compared with the original membrane. Microalgae harvesting results illustrated that the membrane has a high flux recovery rate (FRR) of 98.2%, showed excellent passive antifouling and active antifouling performance. We believe this work will spark a novel platform for optimizing energy-efficient microalgae harvesting separation membrane modules. In addition, this method of anti-fouling filtration for microorganisms can be extended to the industrial production of various bioenergy sources and will have very promising practical applications. 相似文献
13.
Quantum dot (QD) nanoparticles (NPs) are of great interest to various researchers due to their wide range of applications, from photovoltaic sensitizers to in vivo fluorescent probes. There is a need to characterize environmental fate, degradation, and ecotoxicity of QDs because these NPs may be introduced into the environment upon disposal of waste products containing QDs following the anticipated increase in their production and use. Because the properties of QDs are defined primarily by their composition and size, it is imperative that QD size be measured accurately and quickly. Current methods for measuring the size of QDs tend to be relatively slow, require large amounts of sample and may not be suitable for environmental or biological samples. Capillary zone electrophoresis (CZE), with its inherently high separation efficiency based on the size-to-charge ratio of analytes, holds promise for efficient size determination of NPs in aqueous samples.This review examines the potential use of CZE in characterizing and separating QDs compared to the conventional methods employed in determining size distribution of NPs. We briefly discuss the advantages and the limitations of commonly used techniques for size characterization.In addition to published literature, we present results from our laboratory using CZE with laser-induced fluorescence (LIF) to examine the effect of natural organic matter and buffer composition on the electrophoretic mobility of QDs. The use of CZE in environmental studies can provide insights into the degradation and the potential impacts of QDs upon exposure to environmental and biological matrices. 相似文献
14.
When nanoparticles (NPs) enter a biological environment, medium components, especially proteins, compete for binding to the NP’s surface, leading to development of a new interface, commonly referred to as the “protein corona.” This rich protein shell gives the NPs a biological identity that can be very different from their synthetic one, in terms of their chemical–physical properties. Understanding NP–protein interaction is crucial for both the bioapplications and safety of nanomaterials. The protein corona provides the primary contact to the cells and their receptors. It defines in vivo fate of the delivery systems, governing the stability, immunogenicity, circulation, clearance rates and organ biodistribution of the NPs. Given its importance, the application and the development of analytical methods to investigate the protein corona are crucial. This review gives an overview of chromatographic, electrophoretic, mass spectrometric and proteomic methods because these techniques have the advantage to be able to identify and quantify individual proteins adsorbed onto the corona. This capability opens up the possibility to exploit the protein corona for specific cell targeting. 相似文献
15.
Shape-persistent purely organic molecular architectures have attracted tremendous research interest in the past few decades. Dynamic Covalent Chemistry (DCvC), which deals with reversible covalent bond formation reactions, has emerged as an efficient synthetic approach for constructing these well-defined molecular architectures. Among various dynamic linkages, the formation of ethynylene linkages through dynamic alkyne metathesis is of particular interest due to their high chemical stability, linearity, and rigidity. In this review, we focus on the synthetic strategies of discrete molecular architectures ( e.g., macrocycles, molecular cages) containing ethynylene linkages using alkyne metathesis as the key step, and their applications. We will introduce the history and challenges in the synthesis of those architectures via alkyne metathesis, the development of alkyne metathesis catalysts, the reported novel macrocycle structures, molecular cage structures, and their applications. In the end, we offer an outlook of this field and remaining challenges.The recent synthesis of novel shape-persistent 2D and 3D molecular architectures via alkyne metathesis is reviewed and the critical role of catalysts is also highlighted. 相似文献
16.
In the present work, the properties of ZnO nanoparticles obtained using an eco-friendly synthesis (biomediated methods in microwave irradiation) were studied. Saponaria officinalis extracts were used as both reducing and capping agents in the green nanochemistry synthesis of ZnO. Inorganic zinc oxide nanopowders were successfully prepared by a modified hydrothermal method and plant extract-mediated method. The influence of microwave irradiation was studied in both cases. The size, composition, crystallinity and morphology of inorganic nanoparticles (NPs) were investigated using dynamic light scattering (DLS), powder X-ray diffraction (XRD), SEM-EDX microscopy. Tunings of the nanochemistry reaction conditions (Zn precursor, structuring agent), ZnO NPs with various shapes were obtained, from quasi-spherical to flower-like. The optical properties and photocatalytic activity (degradation of methylene blue as model compound) were also investigated. ZnO nanopowders’ antibacterial activity was tested against Gram-positive and Gram-negative bacterial strains to evidence the influence of the vegetal extract-mediated synthesis on the biological activity. 相似文献
17.
Mesoporous late-transition metal oxides have great potential in applications of energy,catalysis and chemical sensing due to their unique physical and chemical properties.However,their synthesis via the flexible and scalable soft-template method remain a great challenge,due to the weak organic-inorganic interaction between the frequently used surfactants(e.g.,Pluronic-type block copolymers) and metal oxide precursors,and the low crystallization temperature of metal oxides.In this study,ordered mesoporous NiO with dual mesopores,high surface area and well-interconnected crystalline porous frameworks have been successfully synthesized via the facile solvent evaporation-induced co-assembly(EICA) method,by using lab-made amphiphilic diblock copolymer polystyrene-b-poly(4-vinylpyridine)(PS-b-P4 VP) as both the structure-directing agent(the soft template) and macromolecular chelating agents for nickel species,THF as the solvent,and nickel acetylacetonate(Ni(acac)2) as inorganic precursor.Similarly,by using Ni(acac)2 and Fe(acac)3 as the binary precursors,ordered mesoporous Fedoped NiO materials can be obtained,which have bimodal mesopores of large mesopores(32.5 nm) and secondary mesopores(4.0-11.5 nm) in the nanocrystal-assembled walls,high specific surface areas(~74.8 m~2/g) and large pore value(~0.167 cm~3/g).The obtained mesoporous Fe-doped NiO based gas sensor showed superior ethanol sensing performances with good sensitivity,high selectivity and fast response-recovery dynamics. 相似文献
18.
Nanotechnology and biomedical sciences open the door to a wide range of biological research topics and medical applications at the molecular and cellular levels. Biosynthesis of nanoparticles has been proposed as a cost-effective and environmentally friendly alternative to chemical and physical methods. Plant-mediated synthesis of nanoparticles is a green chemistry approach that connects nanotechnology with plants. Novel methods of ideally synthesizing NPs are thus proposed that are formed at ambient temperatures, neutral pH, low costs and in an environmentally friendly fashion. The goal of the current study is to examine the cytotoxic activity of hydroxyapatite nanoparticles in various kinds of human cancer cells and potential mechanisms at play. Hydroxyapatite nanoparticles were created by the sol–gel method using lemon extract as a capping and reducing agent to achieve environmentally friendly synthesis. The synthesized nanoparticles were characterized by XRD, SEM, FTIR, TGA, VSM and HRTEM. They were tested for cytotoxicity against T98 and SH-SY5Y, two human cancer cell lines. The synthesized nanostructures significantly caused in vitro cell death in cancer cells. The results confirmed that synthesized nanoparticles significantly decreased the percentage of cells that survived. Nevertheless, it is essential to perform more investigations to find out the exact mechanisms involved. Binding energy of Hydroxyapatite- SH-S5YS complex and Hydroxyapatite- T98 complex calculated by molecular docking. However, it is essential to perform more investigations to find the underlying mechanisms. 相似文献
19.
Green chemistry is playing an important role for synthesizing organic compounds, due to its eco-friendly nature and low cost. In green chemistry, metal nanoparticles exhibited some useful physical and chemical properties (catalytic activity). Due to its diverse properties, nanoparticles can be utilized as a catalyst in various organic reactions. Recent research has been directed towards the utilization of eco- friendly and bio-friendly plant materials in nanoparticles synthesis. In our present work, TiO2 nanoparticles (TiO2 NPs) were synthesized using Annona squamosa peel extract and their catalytic applications were studied on the 2,3-disubstituted dihydroquinazolin-4(l1H)-one synthesis. Synthesized compounds were confirmed using FT-IR.1H NMR, 13C NMR and GC-MS analyses. 相似文献
20.
After a very brief introduction into the impact of living polymerization on preparative polymer chemistry and a look into the dearth of de novo polymer synthesis research for novel biopolymers, this presentation will focus on a new class of synthetic biopolymers: amphiphilic chame- leon networks, i.e., biocomponent networks comprising random strands of hydrophobic and hydrophilic polymers, for blood contact application and mainly for use as narrow diameter (<4 mm) vascular grafts. First, the precision syntheses of amphiphilic networks will be outlined. Subse-quently the surface and bulk characterization of these novel molecular composites by a battery of physicochemical methods will be highlighted. Finally, representative results of biological in-vitro and in-vivo testing will be summarized. We propose that for bio-or hemocompatibility to arise, it may be necessary to employ “smart” amphiphilic surfaces capable of rapid reversible hydrophobic/hydrophilic reorganization so as to present the most favorable lowest energy surface conformation to the medium. It appears that these surfaces are smooth, flexible, and of very low modulus, and that the bulk of these materials have cocontinuous phase-separated microarchitectures with random microdomains in the 10–100 A diameter range. Contemporary macromolecular engineering can deliver materials exhibiting this combination of characteristics. 相似文献
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