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1.
Chempluschem ; 88(6): e202300176, 2023 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-37222183

RESUMO

PCl3 and POCl3 are the most important sources of phosphorus-containing compounds. They are also used for large-scale industrial productions. However, chemical reactions using the highly reactive PCl3 and POCl3 tend to result in overreactions. In addition, the reactions are usually exothermic and therefore their utilization sometimes involves significant risk. That is why some phosphorylating reagents with mild electrophilicity such as phosphoramidites have been developed. Although these mild electrophiles are very useful for the highly selective synthesis of organophosphorus compounds, problems persist: the high cost of the reagents, the generation of large amounts of waste, and the requirement of long reaction times and high temperatures. Continuous-flow technology is one of the most promising solutions for these problems. In particular, precise control of reaction times and temperatures enabled by micro-flow technology suppresses undesired reactions and allows the safe operation of exothermic reactions using highly reactive PCl3 and POCl3 . This Review describes recently reported reactions of PCl3 and POCl3 using continuous- and micro-flow technologies.


Assuntos
Compostos de Fósforo , Compostos de Fósforo/química , Temperatura
2.
Anal Bioanal Chem ; 414(2): 1129-1139, 2022 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-34719746

RESUMO

A label-free electrochemical immunosensor has advantages of real-time and rapid detection, but it is weak in detection of small molecular toxins such as aflatoxin B1 (AFB1). The greatest obstacle to achieving this is that small molecules bound to a common immunosensing interface cannot interfere with electron transfer effectively and the detection signal is so weak. Therefore, a sensitive electrochemical immunosensing interface for small molecules is urgently needed. Here, we employed functionalized black phosphorene (BP) as electrode modification materials and anti-AFB1 nanobody (Nb) as a biorecognition element to construct a very sensitive immunosensing interface towards small molecular AFB1. The BP functionalized by carboxylic multi-walled carbon nanotubes (MWCNTs-COOH) via P-C bonding behaved with a satisfactory stability and good catalytic performance for the ferricyanide/ferrocyanide probe, while the small-sized Nb showed good compatibility with the functionalized BP and also had less influence on electron transfer than monoclonal antibody (mAb). Expectedly, the as-prepared immunosensing interface was very sensitive to AFB1 detection by differential pulse voltammetry (DPV) in a redox probe system. Under optimized conditions, a linear range from 1.0 pM to 5.0 nM and an ultralow detection limit of 0.27 pM were obtained. Additionally, the fabricated immunosensor exhibited satisfactory stability, specificity, and reproducibility. The strategy proposed here provides a more reliable reference for label-free sensing of small molecules in food samples.


Assuntos
Aflatoxina B1/análise , Técnicas Eletroquímicas/métodos , Compostos de Fósforo/química , Anticorpos de Domínio Único/química , Técnicas Biossensoriais/métodos , Limite de Detecção
3.
Chembiochem ; 22(21): 3001-3009, 2021 11 03.
Artigo em Inglês | MEDLINE | ID: mdl-34289217

RESUMO

Known since the 1890s, diamidophosphate (DAP) has been investigated within the context of its inorganic chemistry. In 1999 - with the demonstration of DAP's potential as a phosphorylating agent of sugars in aqueous medium - began the exciting phase of research about DAP's role as a plausible prebiotic phosphorylating agent. More recently, in the last five years, there has been a steady increase in the publications that have documented the surprising versatility of DAP enabling the emergence of many classes of biomolecules of life, such as nucleic acids, peptides and protocells. Thus, though in its infancy, DAP seems to be uniquely positioned to play a central role in modelling abiotic- to prebiotic-chemical evolution. In this context, there is a need for systematic investigations for: (a) establishing DAP's likely availability on the early Earth, and (b) developing DAP's potential as a tool for use in synthetic and bioorganic chemistry.


Assuntos
Indicadores e Reagentes/metabolismo , Compostos de Fósforo/metabolismo , Planeta Terra , Evolução Química , Indicadores e Reagentes/química , Compostos de Fósforo/química , Fosforilação
4.
Bioconjug Chem ; 32(6): 1117-1122, 2021 06 16.
Artigo em Inglês | MEDLINE | ID: mdl-34030446

RESUMO

A cyclotriphosphazene-based "butterfly" fluorescence probe HCCP-MNI bearing two naphthalimide and morpholine units were developed for lysosome targeting. The synthesized HCCP-MNI exhibited stable fluorescence signals and was cytocompatible in the given concentration range. Co-localization experimental results showed that cells treated with the HCCP-MNI and a commercial dye (Lyso-Tracker Red DND-99) had overlapped fluorescence signals, demonstrating its targeting specificity to lysosomes. The developed HCCP-MNI may be used for cell tracking applications associated with the functionalities of lysosomes.


Assuntos
Corantes Fluorescentes/química , Corantes Fluorescentes/metabolismo , Lisossomos/metabolismo , Compostos de Fósforo/química , Espectrometria de Fluorescência
5.
Angew Chem Int Ed Engl ; 60(6): 2952-2957, 2021 02 08.
Artigo em Inglês | MEDLINE | ID: mdl-33128282

RESUMO

RNA-catalyzed RNA ligation is widely believed to be a key reaction for primordial biology. However, since typical chemical routes towards activating RNA substrates are incompatible with ribozyme catalysis, it remains unclear how prebiotic systems generated and sustained pools of activated building blocks needed to form increasingly larger and complex RNA. Herein, we demonstrate in situ activation of RNA substrates under reaction conditions amenable to catalysis by the hairpin ribozyme. We found that diamidophosphate (DAP) and imidazole drive the formation of 2',3'-cyclic phosphate RNA mono- and oligonucleotides from monophosphorylated precursors in frozen water-ice. This long-lived activation enables iterative enzymatic assembly of long RNAs. Our results provide a plausible scenario for the generation of higher-energy substrates required to fuel ribozyme-catalyzed RNA synthesis in the absence of a highly evolved metabolism.


Assuntos
RNA Catalítico/metabolismo , RNA/metabolismo , Biocatálise , Concentração de Íons de Hidrogênio , Imidazóis/química , Cinética , Compostos de Fósforo/química , RNA/química , RNA Catalítico/química
6.
Chem Soc Rev ; 50(4): 2260-2279, 2021 Mar 01.
Artigo em Inglês | MEDLINE | ID: mdl-33367452

RESUMO

Pnictogens (the non-metal phosphorus, metalloids arsenic and antimony, and metal bismuth) possess diverse chemical characteristics that support the formation of extended molecular structures. As witnessed by the centuries-old (and ongoing) clinical utilities, pnictogen-based compounds have secured their places in history as "magic bullet" therapeutic drugs in medicinal contexts. Moreover, with the development of recent metalloproteomics and bio-coordination chemistry, the pnictogen-based drugs functionally binding to proteins/enzymes in biological systems have been underlaid for "drug repurposing" with promising opportunities. Furthermore, advances in the modern materials science and nonotechnology have stimulated a revolution in other newly discovered forms of pnictogens-phosphorene, arsenene, antimonene, and bismuthine (layered pnictogens). Based on their favorable optoelectronic properties, layered pnictogens have shown dramatic superiority as emerging photonic nanomedicines for the treatment of various diseases. This tutorial review outlines the history and mechanism of action of ancient pnictogen-based drugs (e.g., arsenical compounds in traditional Chinese medicine) and their repurposing into modern therapeutics. Then, the revolutionary use of emerging layered pnictogens as photonic nanomedicines, alongside assessments of their in vivo biosafety, is discussed. Finally, the challenges to further development of pnictogens are set forth and insights for further exploration of their appealing properties are offered. This tutorial review may also provide some deep insights into the fields of integrated traditional Chinese and Western medicines from the perspective of materials science and nanotechnology.


Assuntos
Antimônio/química , Arsenicais/química , Bismuto/química , Nanoestruturas/química , Preparações Farmacêuticas/química , Compostos de Fósforo/química , Animais , Antimônio/farmacologia , Arsenicais/farmacologia , Materiais Biocompatíveis/química , Bismuto/farmacologia , Humanos , Imunoterapia , Estrutura Molecular , Nanomedicina , Dispositivos Ópticos , Compostos de Fósforo/farmacologia , Fototerapia , Ligação Proteica , Radioterapia
7.
Molecules ; 25(20)2020 Oct 15.
Artigo em Inglês | MEDLINE | ID: mdl-33076563

RESUMO

In order to explore highly efficient flame-retardant rigid polyurethane foam (RPUF), phosphorus/nitrogen compounds and expandable graphite (EG) were successfully incorporated into RPUF by a free one-spot method. The combustion results showed that the fire safety of the RPUF samples was remarkably improved by the addition of phosphoric/nitrogen compounds and EG. With the incorporation of 22.4 wt.% phosphorus/nitrogen compounds and 3.2 wt.% EG, the RPUF composites achieved UL-94 V-0 rating. Besides, the total heat release and total smoke release of RPUF composites were reduced by 29.6% and 32.4% respectively, compared to those of the pure RPUF sample. PO• and PO2• together with nonflammable gaseous products were evolved from phosphoric/nitrogen compounds in the gas phase, which quenched the flammable free radicals in the matrix and diluted the concentration of combustible gaseous products generated from PRUF during combustion. The compact char residues which acted as excellent physical barriers were formed by catalysis of EG and phosphoric/nitrogen compounds in the condense phase. The fire hazard of RPUF was significantly reduced by the synergistic effect of phosphorus-nitrogen compounds and EG. This work provides a promising strategy to enhance the fire safety of RPUF.


Assuntos
Grafite/química , Compostos de Nitrogênio/química , Compostos de Fósforo/química , Poliuretanos/química , Incêndios/prevenção & controle , Retardadores de Chama/análise , Humanos
8.
Molecules ; 25(17)2020 Aug 19.
Artigo em Inglês | MEDLINE | ID: mdl-32825185

RESUMO

Polystyrene, despite its high flammability, is widely used as a thermal insulation material for buildings, for food packaging, in electrical and automotive industries, etc. A number of modification routes have been explored to improve the fire retardance and boost the thermal stability of commercially important styrene-based polymeric products. The earlier strategies mostly involved the use of halogenated fire retardants. Nowadays, these compounds are considered to be persistent pollutants that are hazardous to public and environmental health. Many well-known halogen-based fire retardants, regardless of their chemical structures and modes of action, have been withdrawn from built environments in the European Union, USA, and Canada. This had triggered a growing research interest in, and an industrial demand for, halogen-free alternatives, which not only will reduce the flammability but also address toxicity and bioaccumulation issues. Among the possible options, phosphorus-containing compounds have received greater attention due to their excellent fire-retarding efficiencies and environmentally friendly attributes. Numerous reports were also published on reactive and additive modifications of polystyrene in different forms, particularly in the last decade; hence, the current article aims to provide a critical review of these publications. The authors mainly intend to focus on the chemistries of phosphorous compounds, with the P atom being in different chemical environments, used either as reactive, or additive, fire retardants in styrene-based materials. The chemical pathways and possible mechanisms behind the fire retardance are discussed in this review.


Assuntos
Poluentes Ambientais/análise , Incêndios/prevenção & controle , Retardadores de Chama/análise , Compostos de Fósforo/análise , Polímeros/análise , Estireno/análise , Poluentes Ambientais/química , Compostos de Fósforo/química , Polímeros/química , Estireno/química
9.
J Drug Target ; 28(7-8): 760-765, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32668995

RESUMO

This article reports enzyme-instructed self-assembly (EISA) of stereoisomers of pentapeptides as a simple approach for generating biocompatible supramolecular hydrogels as potential soft bionanomaterials. Peptide-based supramolecular hydrogels are emerging as a new type of biomaterials. The use of tyrosine phosphate offers a trigger for enzymatic hydrogelation, and the incorporation of D-amino acids can increase the proteolytic stability of peptides. This work compared four phosphorpeptides that are stereoisomers in terms of rate of dephosphorylation, proteolytic stability, and cell compatibility. The results show that the naphthyl (Nap)-capped pentapeptides, containing the amino acid sequence of Phe-Phe-Gly-Glu-pTyr, are able to undergo EISA to form the hydrogels consisting the nanofibres of the dephosphorylated pentapeptides. The naphthyl-capped D-phosphopentpeptides, contrasting to a naphthyl-capped D-phosphotripeptide (Nap-D-Phe-D-Phe-D-pTyr), are largely cell compatible. This result, suggesting that the sequence of phophopeptides also dedicates the cell compatibility of the peptide assemblies resulted from EISA, provides useful insights for developing supramolecular hydrogels as potential biomaterials with tailored properties.


Assuntos
Materiais Biocompatíveis/química , Hidrogéis/química , Peptídeos/química , Nanofibras/química , Compostos de Fósforo/química , Estereoisomerismo
10.
Molecules ; 25(12)2020 Jun 19.
Artigo em Inglês | MEDLINE | ID: mdl-32575624

RESUMO

Ab initio MP2/aug'-cc-pVTZ calculations have been performed to determine the structures and binding energies of complexes formed by phosphatetrahedrane, P(CH)3, and HF, HCl, and ClF. Four types of complexes exist on the potential energy surfaces. Isomers A form at the P atom near the end of a P-C bond, B at a C-C bond, C at the centroid of the C-C-C ring along the C3 symmetry axis, and D at the P atom along the C3 symmetry axis. Complexes A and B are stabilized by hydrogen bonds when FH and ClH are the acids, and by halogen bonds when ClF is the acid. In isomers C, the dipole moments of the two monomers are favorably aligned but in D the alignment is unfavorable. For each of the monomers, the binding energies of the complexes decrease in the order A > B > C > D. The most stabilizing Symmetry Adapted Perturbation Theory (SAPT) binding energy component for the A and B isomers is the electrostatic interaction, while the dispersion interaction is the most stabilizing term for C and D. The barriers to converting one isomer to another are significantly higher for the A isomers compared to B. Equation of motion coupled cluster singles and doubles (EOM-CCSD) intermolecular coupling constants J(X-C) are small for both B and C isomers. J(X-P) values are larger and positive in the A isomers, negative in the B isomers, and have their largest positive values in the D isomers. Intramolecular coupling constants 1J(P-C) experience little change upon complex formation, except in the halogen-bonded complex FCl:P(CH3) A.


Assuntos
Compostos de Fósforo/química , Ligação de Hidrogênio , Modelos Moleculares
11.
Int J Mol Sci ; 21(12)2020 Jun 16.
Artigo em Inglês | MEDLINE | ID: mdl-32560033

RESUMO

Two series of new hexasubstituted cyclotriphosphazene derivatives were successfully synthesized and characterized. These derivatives are differentiated by two types of linking units in the molecules such as amide-azo (6a-j) and azo-azo (8a-j). The homologues of the same series contain different terminal substituents such as heptyl, nonyl, decyl, dodecyl, tetradecyl, hydroxyl, carboxyl, chloro, nitro, and amino groups. All the intermediates and final compounds were characterized using Fourier transform infrared spectroscopy (FT-IR), nuclear magnetic resonance spectroscopy (NMR), and Carbon, Hydrogen, and Nitrogen (CHN) elemental analysis. Liquid crystal properties for all compounds were determined using polarized optical microscope (POM). It was found that only intermediates 2a-e with nitro and alkoxyl terminal chains showed a smectic A phase. All the final compounds with alkoxyl substituents are mesogenic with either smectic A or C phases. However, other intermediates and compounds were found to be non-mesogenic. The study on the fire retardancy of final compounds was determined using limiting oxygen index (LOI) method. The LOI value of pure polyester resin (22.53%) was increased up to 24.71% after treating with 1 wt% of hexachlorocyclotriphosphazene (HCCP). Moreover, all the compounds gave positive results on the LOI values and compound 6i with the nitro terminal substituent showed the highest LOI value of 27.54%.


Assuntos
Compostos Azo/síntese química , Retardadores de Chama/síntese química , Compostos de Fósforo/síntese química , Amidas/química , Compostos Azo/química , Compostos Azo/farmacologia , Retardadores de Chama/farmacologia , Cristais Líquidos/química , Microscopia de Polarização , Estrutura Molecular , Nitrilas/química , Oxigênio/química , Compostos de Fósforo/química , Espectroscopia de Infravermelho com Transformada de Fourier
12.
Chempluschem ; 85(7): 1368, 2020 07.
Artigo em Inglês | MEDLINE | ID: mdl-32491250

RESUMO

Invited for this month's cover is the group of Prof. Kenneth Kam-Wing Lo at City University of Hong Kong, Hong Kong, P. R. China. The cover picture shows the selective landing of a bioorthogonal spacecraft on a lysosomal planet modified with a strained cyclooctyne moiety in an intracellular environment with other organelles and a plethora of biomolecules. A sydnone moiety is appended to a luminescent rhenium(I) diimine unit as both an emission quencher and a bioorthogonal handle. Selective strain-promoted sydnone-alkyne cycloaddition (SPSAC) of the complex with a strained alkyne leads to impressive emission turn-on, which can be exploited in bioimaging and phototherapeutic applications. Read the full text of the article at 10.1002/cplu.202000029.


Assuntos
Lisossomos/química , Compostos de Fósforo/química , Piridinas/química , Rênio/química
13.
Biochim Biophys Acta Bioenerg ; 1861(8): 148210, 2020 08 01.
Artigo em Inglês | MEDLINE | ID: mdl-32305410

RESUMO

An increase in the production of reactive oxygen species (ROS) in mitochondria due to targeted delivery of redox active compounds may be useful in studies of modulation of cell functions by mitochondrial ROS. Recently, the mitochondria-targeted derivative of menadione (MitoK3) was synthesized. However, MitoK3 did not induce mitochondrial ROS production and lipid peroxidation while exerting significant cytotoxic action. Here we synthesized 1,4-naphthoquinone conjugated with alkyltriphenylphosphonium (SkQN) as a prototype of mitochondria-targeted prooxidant, and its redox properties, interactions with isolated mitochondria, yeast cells and various human cell lines were investigated. According to electrochemical measurements, SkQN was more active redox agent and, due to the absence of methyl group in the naphthoquinone ring, more reactive as electrophile than MitoK3. SkQN (but not MitoK3) stimulated hydrogen peroxide production in isolated mitochondria. At low concentrations, SkQN stimulated state 4 respiration in mitochondria, decreased membrane potential, and blocked ATP synthesis, being more efficient uncoupler of oxidative phosphorylation than MitoK3. In yeast cells, SkQN decreased cell viability and induced oxidative stress and mitochondrial fragmentation. SkQN killed various tumor cells much more efficiently than MitoK3. Since many tumors are characterized by increased oxidative stress, the use of new mitochondria-targeted prooxidants may be a promising strategy for anticancer therapy.


Assuntos
Antineoplásicos/farmacologia , Mitocôndrias/efeitos dos fármacos , Naftoquinonas/farmacologia , Espécies Reativas de Oxigênio/farmacologia , Antineoplásicos/química , Linhagem Celular Tumoral , Sobrevivência Celular/efeitos dos fármacos , Humanos , Peróxido de Hidrogênio/metabolismo , Naftoquinonas/química , Fosforilação Oxidativa/efeitos dos fármacos , Oxigênio/metabolismo , Compostos de Fósforo/química , Espécies Reativas de Oxigênio/química
14.
Mater Sci Eng C Mater Biol Appl ; 109: 110535, 2020 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-32228933

RESUMO

We obtained a range of PLGA-based composites containing sol-gel bioactive glasses (SBG) from the SiO2-CaO and SiO2-CaO-P2O5 systems. Eight SBGs with different CaO/SiO2 ratios with and without P2O5 were incorporated at 50% w/w to PLGA matrix and structured into thin films suitable for cell culture. The SBG/PLGA composites were examined for their bioactivity in simulated body fluid (SBF), ion release profile in culture media with and without cells, and osteoinductivity in standard human bone marrow stromal cell (hBMSC) cultures without osteogenic growth factors. Our results indicate different surface activity of composites depending on the presence/absence of P2O5 in SBG composition. Furthermore, ion release profile to culture medium differed depending on the presence/absence of cells. Direct culture of hBMSC on the SiO2-CaO/PLGA composite films resulted in elevated Runx-2 mRNA, opposite to low Runx-2 mRNA levels on SiO2-CaO-P2O5/PLGA films. All studied composites increased Osx mRNA levels. Whereas some of SiO2-CaO/PLGA composites did not elevate BMP-2 and -6 proteins in hBMSC cultures, high levels of these BMPs were present in all cultures on SiO2-CaO-P2O5/PLGA composites. All composites induced BMP-related Tak1 signalling, whereas Smad1 signalling was restricted mostly to composites containing three-component SBGs. ALP activity of hBMSC and BMP-related luciferase activity of mouse BRITE cells differed depending on whether the cells were stimulated with culture medium conditioned with SBG/PLGA composites or the cells were directly cultured on the composite surfaces. Altogether, beyond bioactivity and osteoinductivity of SBG/PLGA composites, our studies show key differences in the biological response to both the bioactive material dissolution products and upon direct cell-material contacts.


Assuntos
Células da Medula Óssea/metabolismo , Regeneração Óssea , Oxalato de Cálcio/química , Vidro/química , Células-Tronco Mesenquimais/metabolismo , Compostos de Fósforo/química , Dióxido de Silício/química , Adulto , Idoso , Animais , Células da Medula Óssea/citologia , Feminino , Géis , Humanos , Masculino , Células-Tronco Mesenquimais/citologia , Camundongos , Pessoa de Meia-Idade , Copolímero de Ácido Poliláctico e Ácido Poliglicólico/química
15.
Molecules ; 25(4)2020 Feb 23.
Artigo em Inglês | MEDLINE | ID: mdl-32102166

RESUMO

A family of complexes of the formula trans-[RuCl2(L)(R-pybox)] (R-pybox = (S,S)-iPr-pybox, (R,R)-Ph-pybox, L = monodentate phosphonite, PPh(OR)2, and phosphinite, L = PPh2(OR), ligands) were screened in the catalytic asymmetric transfer hydrogenation of acetophenone, observing a strong influence of the nature of both the R-pybox substituents and the L ligand in the process. The best results were obtained with complex trans-[RuCl2{PPh2(OEt)}{(R,R)-Ph-pybox}] (2c), which provided high conversion and enantioselectivity (up to 96% enantiomeric excess, e.e.) for the reduction of a variety of aromatic ketones, affording the (S)-benzylalcohols.


Assuntos
Cetonas/química , Oxazóis/química , Compostos de Fósforo/química , Piridinas/química , Rutênio/química , Acetofenonas/química , Catálise , Complexos de Coordenação/química , Cristalografia por Raios X , Hidrogenação , Isomerismo , Ligantes , Fosfinas/química , Fosfitos/química
16.
ACS Appl Mater Interfaces ; 12(9): 10781-10790, 2020 Mar 04.
Artigo em Inglês | MEDLINE | ID: mdl-32048821

RESUMO

The evaluation of intracellular reactive oxygen species (ROS) would greatly deepen the understanding of cell metabolism/proliferation and tumor detection. However, current long-acting level tracking techniques for intracellular ROS remain unsuited to practical applications. To solve this problem, we synthesized cyclotriphosphazene-doped graphene quantum dots (C-GQDs) whose quantum yield is highly sensitive to ROS (increased by 400% from 0.12 to 0.63). Electron cloud polarization of oxidized cyclotriphosphazene rings in C-GQDs is confirmed to account for this novel optical property by density functional theory calculations and experimental results. In combination with excellent biological stability, C-GQDs achieve a long-acting evaluation of intracellular ROS level (more than 72 h) with an accuracy of 98.3%. In addition, recognition rates exceeding 90% are demonstrated to be feasible for eight kinds of tumor cell lines cultured with C-GQDs, which can also be expanded to in vivo detection. C-GQDs also show a high recognition rate (82.33%) and sensitivity (79.65%) for tumor cells in blood samples.


Assuntos
Grafite/química , Medições Luminescentes/métodos , Neoplasias/metabolismo , Pontos Quânticos/química , Espécies Reativas de Oxigênio/análise , Animais , Linhagem Celular Tumoral , Humanos , Luminescência , Medições Luminescentes/instrumentação , Camundongos , Camundongos Endogâmicos BALB C , Neoplasias/diagnóstico , Oxirredução , Compostos de Fósforo/química , Espécies Reativas de Oxigênio/metabolismo
17.
Spectrochim Acta A Mol Biomol Spectrosc ; 229: 118000, 2020 Mar 15.
Artigo em Inglês | MEDLINE | ID: mdl-31935656

RESUMO

Bioceramics of composition xCr2O3∙(43-x) CaO∙42SiO2∙15P2O5 (x varying from 0 to 8 mol%) have been synthesized in the laboratory by using sol-gel technique. The morphology and structure has been determined by using Powder X-ray Diffraction, Fourier Transform Infrared and Raman spectroscopy and Field Emission Scanning Electron Microscopy. The in vitro bio mineralization behavior has been assessed by immersion in simulated body fluid for 7 days. The results obtained in our studies have indicated excellent hydroxyapatite formation ability of our samples. Drug delivery property of synthesized samples has been checked by using UV-spectroscopy of antibiotic 'gentamicin'. The in vitro drug release profile was fitted best in the Higuchi model with the highest value of coefficient of determination (R2 = 0.9970). Antimicrobial properties have been evaluated from minimum inhibitory concentration and time kill assay values. The cellular response has been investigated by using human osteosarcoma MG 63 cell line. Also to check charge on the synthesized samples, Zeta potential studies have been conducted and it has been observed that samples carry negative charge when immersed in simulated body fluid. Negative surface charge provide suitable environment for cell adhesion and proliferation. Experiments have been undertaken to explore suitable composition with an objective of development of suitable implant material for bone regeneration applications.


Assuntos
Bactérias/efeitos dos fármacos , Materiais Biocompatíveis/farmacologia , Regeneração Óssea/efeitos dos fármacos , Sobrevivência Celular , Cerâmica/farmacologia , Compostos de Cromo/química , Antibacterianos/química , Antibacterianos/farmacologia , Neoplasias Ósseas/tratamento farmacológico , Neoplasias Ósseas/metabolismo , Neoplasias Ósseas/patologia , Compostos de Cálcio/química , Humanos , Osteossarcoma/tratamento farmacológico , Osteossarcoma/metabolismo , Osteossarcoma/patologia , Compostos de Fósforo/química , Dióxido de Silício/química , Propriedades de Superfície , Células Tumorais Cultivadas
18.
Anal Chem ; 91(22): 14666-14671, 2019 11 19.
Artigo em Inglês | MEDLINE | ID: mdl-31697065

RESUMO

Detection of inorganic phosphate is very important in environmental and health care applications. In this work, we found that phenomenon similar to "catalytic hydrogen wave" occurred on a molybdenum phosphide (MoP) modified electrode in the presence of phosphate, that is, a new wave of catalytic hydrogen evolution appeared before the normal hydrogen evolution reaction. The catalytic hydrogen wave arose from a structure similar to phosphomolybdic acid (noted as MoPO), which was formed by the interaction between phosphate and molybdenum oxides on the surface of the MoP modified electrode, resulting in the altered surface structure and adjusted interface catalytic activity. A novel phosphate electrochemical sensor was constructed based on this phenomenon with a linear range from 0.10 to 20.0 mmol·L-1, an actually determined minimum concentration of 0.030 mmol·L-1, and recoveries of 94%-107%, and this sensor was successfully applied to the detection of phosphate in human blood. Furthermore, this work proposes a new sensing method based on catalytic hydrogen waves on the modified electrodes.


Assuntos
Hidrogênio/química , Molibdênio/química , Fosfatos/sangue , Compostos de Fósforo/química , Catálise , Técnicas Eletroquímicas/instrumentação , Técnicas Eletroquímicas/métodos , Eletrodos , Humanos , Óxidos/química
19.
Biochem Pharmacol ; 170: 113668, 2019 12.
Artigo em Inglês | MEDLINE | ID: mdl-31628909

RESUMO

Human Vγ9Vδ2 T cells respond to small phosphorus-containing compounds, often called phosphoantigens, which are now known to be intracellular ligands of the immune receptor butyrophilin 3A1 (BTN3A1). In order to compare the efficiency of butyrophilin ligands, we developed a luciferase-based lysis assay that measures the direct cytolysis by Vγ9Vδ2 T cells of luciferase-expressing K562 leukemia cells sensitized by phosphoantigen prodrugs. Our results show that the luciferase-based lysis assay allows in vitro and in vivo assessment of phosphoantigen activity in a way that does not require the extensive processing of flow cytometry or ELISA based approaches. In cellular assays, the structure activity relationships of phosphoantigen prodrugs correlate with ELISA-based activation assays, though phosphoantigen induced target cell lysis occurs at lower concentrations relative to T cell interferon γ production measured by ELISA. In mice dosed with phosphoantigens, a racemic aryl phosphonamidate prodrug, methyl 2-[[[(E)-5-hydroxy-4-methyl-pent-3-enyl]-(1-naphthyloxy)phosphoryl]amino]acetate (1-Nap/GlyOMe C-HMBP, 5), sensitized subcutaneous K562 tumors within minutes, and this effect was maintained at least four hours after treatment. In vivo activity of compound 5 was stronger than that of an equivalent dose of zoledronate. This luciferase lysis assay can be used for evaluation of phosphoantigens due to its time efficiency, high sensitivity, and in vivo compatibility and demonstrates rapid in vitro and in vivo sensitization of tumor cells by phosphoantigen prodrugs.


Assuntos
Leucócitos Mononucleares/enzimologia , Luciferases/metabolismo , Organofosfatos/farmacologia , Pró-Fármacos/farmacologia , Animais , Relação Dose-Resposta a Droga , Humanos , Células K562 , Leucócitos Mononucleares/efeitos dos fármacos , Camundongos , Camundongos da Linhagem 129 , Camundongos Knockout , Organofosfatos/química , Compostos de Fósforo/química , Compostos de Fósforo/farmacologia , Pró-Fármacos/química , Ensaios Antitumorais Modelo de Xenoenxerto/métodos
20.
J Mech Behav Biomed Mater ; 100: 103379, 2019 12.
Artigo em Inglês | MEDLINE | ID: mdl-31398691

RESUMO

Bioactive ceramics, glasses and glass ceramics have the ability to enhance the bone formation and bond to surrounding tissue. In this study, we report on the synthesis of mesoporous nanobioactive glass ceramic with the modified composition of quaternary system 50% SiO2 - 26% Na2O - 20% CaO- 4% P2O5 (Ca/P: 5) [i.e.50S20C] by sol-gel method and succeeded by heat treatment. The as-dried sample was calcined at various temperatures such as 100 °C, 300 °C, 500 °C, 700 °C and 900 °C for 24 h.The weight loss measurement was carried out using Thermogravimetric (TG) analysis. The structural features were characterized by X-ray diffraction (XRD), Fourier transformed infrared spectroscopy (FTIR), Field Emission Scanning Electron Microscopy (FESEM) & Energy Dispersive Spectroscopy (EDS) analysis. The results revealed that the synthesized glass ceramic stabilized at higher temperature (700 °C and 900 °C)making more formation of the crystalline phase of sodium calcium silicate. The density and porosity measurements were carried out by using the Archimedes immersion method. The mechanical properties of the glass ceramic exhibit the compressive strength as69 MPa and 72 MPa for 700 °C and 900 °C, respectively. From the obtained results, we confirmed the calcined bioactive glass ceramic nanoparticles at 700 °C and 900 °C having a better crystallization, crystallite size with high surface area, high density, suitable porosity of mesoporous with dense microstructure and adequate mechanical properties. Furthermore, in vitro bioactivity character of calcined nanobioactive glass ceramics were studied by using an immersion of nanopowders into Stimulated Body Fluid (SBF) solution for two different time periods such as 7 and 14 days. After soaking the glass ceramic nanopowders in SBF, the structural and morphological changes were determined by using XRD, FTIR and FESEM & EDS analysis, respectively. The in vitro results exhibited that crystallization did not retard the samples bioactivity which indicates the increase of material bioactivity while calcining temperature was increased and it is used to fabricate tissue engineering scaffolds with sustained mechanical properties. Moreover, the enhanced bactericidal behavior of glass ceramic has also been studied. An antibacterial study revealed that the prepared bioactive glass ceramic show a significant effect on two bacteria E. coli and S. aureus.


Assuntos
Antibacterianos/farmacologia , Materiais Biocompatíveis/química , Compostos de Cálcio/química , Cerâmica/química , Óxidos/química , Compostos de Fósforo/química , Dióxido de Silício/química , Compostos de Sódio/química , Antibacterianos/química , Apatitas/química , Regeneração Óssea , Carbonatos/química , Força Compressiva , Escherichia coli , Vidro/química , Temperatura Alta , Humanos , Transição de Fase , Porosidade , Espectroscopia de Infravermelho com Transformada de Fourier , Estresse Mecânico , Propriedades de Superfície , Termogravimetria , Engenharia Tecidual/métodos
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