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1.
J Environ Manage ; 259: 110011, 2020 Apr 01.
Artigo em Inglês | MEDLINE | ID: mdl-32072958

RESUMO

Bimetallic nanoparticles are the complex combination of two different metal constituents in nanoscale. Water and wastewater treatment utilizing bimetallic particles is an emerging research area. When two metals are combined, it can show not only the properties of its constituents but also new and enhanced properties derived by the synergy of the combination. These properties of bimetallic nanoparticles inevitably depend on the size, structure, and morphology of the particles. Thus the adopting synthesis strategy is very crucial to achieve desired results. Here in this review, the various bimetallic synthesis strategies are compared. The bimetallic nanoparticles decontaminate water through adsorption and/or catalysis mechanism. The various degradation pathways, specifically, adsorption, reduction, oxidation, and advanced oxidation processes are discussed in detail in this review.


Assuntos
Nanopartículas Metálicas , Nanoestruturas , Catálise , Oxirredução , Águas Residuárias , Água
2.
J Biomed Nanotechnol ; 16(1): 111-124, 2020 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-31996290

RESUMO

Radiation therapy is a mainstay in the therapeutic management of Head and Neck Squamous Cell Carcinoma (HNSCC). Despite significant progress in this field, radioresistance still accounts for most treatment failures. Gadolinium-based nanoparticles (GBNs) have shown great promises as radiosensitizers but the underlying sensitizing mechanism is still largely unknown with regards to the disparities obtained in in vitro studies. In this study, we show that a new formulation of GBNs, AGuIX®, can radiosensitize HNSCC after cell uptake and further accumulation in lysosomes. Although radiation alone triggered late apoptosis and mitochondrial impairment, the pre-treatment with GBNs led to complex DNA damage and a specific increase of autophagic cell death. In addition, a significant radio-enhancement effect was obtained after the pre-conditioning of cells with a glutathione inhibitor before GBNs treatment and radiation exposure. Overall, our results provide additional information on the radio-enhancing properties of GBNs in the management of radioresistant HNSCC.


Assuntos
Autofagia , Carcinoma de Células Escamosas , Neoplasias de Cabeça e Pescoço , Carcinoma de Células Escamosas de Cabeça e Pescoço , Apoptose , Linhagem Celular Tumoral , Gadolínio , Humanos , Nanopartículas Metálicas
3.
Water Res ; 171: 115399, 2020 Mar 15.
Artigo em Inglês | MEDLINE | ID: mdl-31896028

RESUMO

Silver based nanoparticles (Ag-b-NPs) in the environment are of current concern as they may pose risks to human and environmental health, even at low concentration levels. It is widely known that Ag-b-NPs, once released from products containing these particles for antimicrobial reasons, can pass through wastewater treatment plants to some extent. These particles are transported via running waterways and eventually reach the sea. However, the fate of environmentally relevant ng L-1 traces of Ag-b-NPs in seawater has not yet been sufficiently studied. Analytical techniques capable of determining these ultratraces of Ag-b-NPs in seawater are scarce and struggle furthermore with the high chloride content in highly saline matrices, such as seawater. In this study, we extracted Ag-b-NPs from matrices with varying salinity via cloud point extraction (CPE) and determined concentration and size of Ag-b-NPs in extracts with single particle inductively coupled plasma mass spectrometry (sp-ICP-MS). Applying this extraction and measurement technique, we were able to investigate the fate of Ag-b-NPs with different coatings (citrate and the predominant coatings in nature, silver sulfide and silver chloride) in matrices with increasing salinity and real seawater. All types of Ag-b-NPs were dissolved in all matrices almost independently of the chemical composition of the nanoparticles (NPs), whereas dissolution rates increased with increasing salinity due to the formation of soluble Ag(I) species and - in the presence of chloride - AgClx1-x (x > 1) complexes. After an incubation time of not more than 72 h, Ag-b-NPs were dissolved almost completely. During the dissolution process, NP shrinkage could be clearly observed by sp-ICP-MS. Supplementary electron microscopy measurements revealed that the sulfur content in silver sulfide nanoparticles (Ag2S-NPs) increased during the dissolution process. Finally, we were able to investigate the dissolution process of real Ag-b-NPs in wastewater after increasing the salinity to seawater levels.


Assuntos
Nanopartículas Metálicas , Prata , Humanos , Água do Mar , Sulfetos , Águas Residuárias
4.
J Photochem Photobiol B ; 203: 111762, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31896049

RESUMO

Activation of photocatalytic titania by ultraviolet-A (UVA) radiation has been proposed as a good approach for combating bacteria. Titania powder, in solution or immobilized on a surface, has excellent UVA-assisted killing properties on several microorganisms. However, these properties could not be demonstrated in biofilms of Pseudomonas aeruginosa, a resistant opportunistic human pathogen that can cause severe complications in patients who are immunocompromised or have burn wounds or cystic fibrosis. P. aeruginosa biofilms have detrimental effects on health and industry, causing serious economic damage. In this study, the effect of titania photocatalysis for controlling P. aeruginosa biofilms was investigated by employing different coatings obtained through sol-gel and evaporation-induced self-assembly. Biofilms were grown on non-mesoporous and mesoporous titania surfaces with different pore sizes, which were achieved based on the use of surfactants Brij-58 and Pluronics-F127. In addition, two structural forms of titania were assayed: amorphous and anatase. As well as inhibiting biofilm formation, these coatings significantly enhanced the bactericidal effect of UVA on P. aeruginosa biofilms. The most efficient surface with regard to total antibacterial effect was the mesoporous Brij-58-templated anatase film, which, compared to control biofilms, decreased the number of viable bacteria by about 5 orders, demonstrating the efficacy of this methodology as a disinfection system.


Assuntos
Biofilmes/efeitos dos fármacos , Nanopartículas Metálicas/toxicidade , Pseudomonas aeruginosa/fisiologia , Titânio/química , Raios Ultravioleta , Biofilmes/efeitos da radiação , Catálise , Nanopartículas Metálicas/química , Porosidade , Tensoativos/química
5.
J Photochem Photobiol B ; 203: 111741, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31901721

RESUMO

Spinal cord injury (SCI) is a distressing injury and an irretrievable dramatic event that can debilitate victims for lifespan. Recovery and treatment of SCI is critical challenges for medicine, to overcome the hurdles stem cells and hydrogel scaffolds implantation is a boon for SCI recovery. In this regard, we reported the synthesis of Gold nanoparticles (Au NPs) loaded Agarose/Poly (N-isopropylacrylamide) (PNIPAM) as promising materials for SCI treatment. Herein, Au NPs was synthesized by well-established citrate reduction method and the prepared materials were characterised by UV-visible spectroscopy (UV-vis), Transmission electron microscopy (TEM), Fourier- transform infrared spectroscopy (FT-IR), Scanning electron microscopy (SEM), and EDAX analysis. The microscopic images showed an elliptical or ovoid porous structure nature of hydrogel, and successful and homogenous loading of photo plasmonic nanoparticles into the hydrogel structure. The in vitro cell viability and inflammation analyses data exhibited that prepared hydrogels have no toxic to the cells and displayed high anti-regenerative ability with bone marrow Mesenchymal stem cells (MSCs) and macrophages cells. The in vivo analysis study demonstrated that the treated materials with encapsulated MSCs have greater nerve tissue regeneration efficacy which was confirmed by the results of BBB scores. The hind limb locomotion of treated model animals was totally vanished after post-operational surgery. It's established that implanted nano-hydrogel materials combined with MSCs have quicker recovery of motor function after post-operative surgery, when compared to the other implanted animal groups.


Assuntos
Materiais Biocompatíveis/química , Hidrogéis/química , Transplante de Células-Tronco Mesenquimais , Nanopartículas Metálicas/química , Traumatismos da Medula Espinal/terapia , Bexiga Urinária/fisiopatologia , Resinas Acrílicas/química , Animais , Células da Medula Óssea/citologia , Ouro/química , Membro Posterior/fisiologia , Locomoção , Células-Tronco Mesenquimais/química , Células-Tronco Mesenquimais/citologia , Tecido Nervoso/fisiologia , Regeneração , Traumatismos da Medula Espinal/complicações , Traumatismos da Medula Espinal/patologia , Tecidos Suporte/química
7.
J Photochem Photobiol B ; 203: 111748, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31918235

RESUMO

Nanotechnology is an emerged field to develop the plant mediated metal based nanodrugs by green method. In this current study, the zinc oxide metal based nanoparticles were developed using (Clausena lansium (Lour.) Skeels) Peel aqueous extracts and zinc nitrate. The C.L extract zinc nanoparticleswere indicated by the sharp peak seen at 350 nm utilizing the Ultraviolet-Visible spectroscopy (UV-Vis). The high peaks indicate the presence of phytochemicals and its functional groups in ZnONPs were studied by the Fourier Transform Infrared Spectroscopy (FT-IR). The X-Ray Diffraction analysis (XRD) explores the pattern and structure of ZnONPs as spherical and base-centered monoclinic crystalline shapes. The C.L extract with Zn nanoparticles were spherical in nature and the size of the synthesized particles were about 28.42 nm respectively. The autophagy (Beclin-1, LC3-I, LC3-II and ATG4B) and apoptotic (Bax, Bcl-2 and Caspase-3) proteins were regulated by the treatment with ZnONPs in SH-SY5Y neuroblastoma cells. The DNA loss or damage was occurred in the ZnONPs treatment and it was performed using Comet assay. The ZnONPs treatment generates the ROS in the cells and decreased its stability and viability. Addition of NAC prevents ROS in the cultured SH-SY5Y cells and prevents the cells from the apoptosis. We concluded that the ZnONPs potentially kills the neuroblastoma cells by producing the intracellular ROS.


Assuntos
Antineoplásicos/farmacologia , Autofagia/efeitos dos fármacos , Nanopartículas Metálicas/química , Óxido de Zinco/química , Antineoplásicos/química , Apoptose/efeitos dos fármacos , Proteína Beclina-1/metabolismo , Caspase 3/metabolismo , Linhagem Celular Tumoral , Sobrevivência Celular/efeitos dos fármacos , Clausena/química , Clausena/metabolismo , Dano ao DNA/efeitos dos fármacos , Química Verde , Humanos , Nanopartículas Metálicas/toxicidade , Neuroblastoma/metabolismo , Neuroblastoma/patologia , Extratos Vegetais/química , Proteínas Proto-Oncogênicas c-bcl-2/metabolismo , Espécies Reativas de Oxigênio/metabolismo
8.
J Photochem Photobiol B ; 203: 111770, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31918236

RESUMO

Dopamine (DA) is a monoamine neurotransmitter of phenethylamine and catecholamine families, which is present in the central nervous system (CNS) and its periphery. Since DA is associated with several functions in the brain and body (motivational salience, reward, motor control, paracrine messenger, etc.), any imbalance in the DA level can trigger several neurodegenerative and other diseases. On the other hand, the spherical gold nanoparticles (AuNPs) can be used for drug delivery in several parts of the body. In addition, AuNPs also have the potentiality to penetrate through the blood-brain barrier and interact with the central nervous system without causing any toxicity. In view of many applications, it is important to look into the interaction between DA and AuNPs for a potential drug delivery model in DA related diseases. Here, we have used the steady-state and time-resolved fluorescence spectroscopic tools to investigate the binding interaction of DA with AuNPs. The nature of the quenching mechanism was confirmed through both steady-state and time-resolved fluorescence measurements. The binding constants along with the number of binding sites were estimated from the steady-state fluorescence measurements. The distance between DA and AuNPs was calculated using Förster's theory to verify the possibility of fluorescence resonance energy transfer (FRET) from DA to AuNPs.


Assuntos
Dopamina/química , Ouro/química , Nanopartículas Metálicas/química , Sítios de Ligação , Transferência Ressonante de Energia de Fluorescência , Espectrometria de Fluorescência , Termodinâmica
9.
J Photochem Photobiol B ; 203: 111778, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31931389

RESUMO

In the last decade, gold nanoparticles have emerged as promising agents for in vitro bio-sensing and in vivo cancer theranostics. However, different investigations have reported widely varying cytotoxicity and uptake efficiency of gold nanoparticles depending upon their size. Therefore, more extensive studies are needed to standardize these biological effects as a function of size on a particular cell line. In addition, to obtain robust confirmation on the correlation of a size to biological effect, thorough mechanistic study must also be performed. In this study, the size dependent biological activities of gold nanoparticles on osteosarcoma cells is investigated towards exploring their potential theranostic application in bone cancer, for which very scarce literature reports are available. Tris-assisted citrate based method was optimized to synthesize stable gold naoparticles of 40-60 nm sizes. Nanoparticles were characterized through UV-Vis spectroscopy, field emission scanning electron microscope (FESEM) and dynamic light scattering (DLS). Increasing concentrations of gold nanoparticles (AuNPs) of 46 nm size, enhanced the rate of reactive oxygen species (ROS)-induced apoptosis in MG63 cells by disrupting their mitochondrial membrane potential. Considerably higher cell death was observed for 46 and 60 nm AuNPs compared to 38 nm at all concentrations of 200, 400 and 800 ng/mL. Further, molecular signatures of cellular apoptosis under nanoparticle treatment were optically assessed through surface enhanced Raman scattering (SERS). A significant Raman enhancement in cancer cells under treatment of larger gold nanoparticles (46 and 60 nm) at fixed wavelength of 785 nm and laser power of 8.0 mW was evident. In corroboration with molecular biology techniques, SERS observation confirmed the size-dependent apoptotic phenomena in osteosarcoma cells under treatment of gold nanoparticles. Study demonstrates a facile, non-active targeting approach for detection of size-dependent AuNP-induced apoptosis in osteosarcoma cells through label-free SERS method.


Assuntos
Apoptose/efeitos dos fármacos , Ouro/química , Nanopartículas Metálicas/toxicidade , Caspase 3/metabolismo , Linhagem Celular Tumoral , Difusão Dinâmica da Luz , Humanos , Potencial da Membrana Mitocondrial/efeitos dos fármacos , Nanopartículas Metálicas/química , Microscopia de Fluorescência , Osteossarcoma/metabolismo , Osteossarcoma/patologia , Tamanho da Partícula , Espécies Reativas de Oxigênio/metabolismo , Análise Espectral Raman
10.
Water Res ; 171: 115436, 2020 Mar 15.
Artigo em Inglês | MEDLINE | ID: mdl-31931376

RESUMO

The wide use of silver nanoparticles (Ag NPs) inevitably leads to their increasing emission into aquatic environments. However, before their final deposition into sediments, the ecological effects of Ag NPs in suspended sediment (SPS) systems have not received much attention. Herein, we investigated the influences of Ag NPs on denitrification in SPS systems, and explored the potential toxicity mechanism through microbial metabolism (electron behaviors) and isotope tracing (added 15NO3-). After exposure to 10 mg/L Ag NPs, electron generation, transport and consumption during denitrification were clearly inhibited, which led to a decrease in the SPS denitrification rate. Specifically, the generation of NADH (electron donor) was significantly decreased to 59.92-86.47% with the Ag NPs treatments by affecting the degradation of glucose, one of the major reasons for the decreased denitrification. It also indicated that Ag NPs could affect nitrogen metabolism by influencing carbon metabolism. In addition, ETSA was clearly inhibited by the affected electron transfer and reception during denitrification; that was the most direct way in the microbial electron transport chain to affect the SPS denitrification rate. Furthermore, the particle size and concentration of SPS affected the toxicity of Ag NPs. The denitrification process in SPS systems with a smaller particle size and lower particle concentration was easily affected by Ag NPs, suggesting that SPS systems dominated by clay (particle size < 3.9 µm) or that less turbulence (having low SPS concentration) might be at greater risk factor when exposed to NPs. Thus, it is important to understand the risks of pollutants, such as Ag NPs, to biogeochemical cycles and ecosystem function in SPS systems.


Assuntos
Desnitrificação , Nanopartículas Metálicas , Ecossistema , Elétrons , Prata
11.
Anal Bioanal Chem ; 412(4): 915-922, 2020 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-31900531

RESUMO

A tetrahedral DNA probe can effectively overcome the steric effects of a single-stranded probe to obtain well-controlled density and minimize nonspecific adsorption. Herein, a highly sensitive electrochemical biosensor is fabricated for determination of protein using a tetrahedral DNA probe and rolling circle amplification (RCA). N- and P-co-doped graphene (NP-rGO) is prepared, and AuNPs are then electrodeposited on it for DNA probe immobilization. Benefitting from the synergistic effects of the excellent electrical conductivity of NP-rGO, the stability of the tetrahedral DNA probe and the signal amplification of RCA, the biosensor achieves a low limit of 3.53 × 10-14 M for thrombin and a wide linear range from 1 × 10-13 to 1 × 10-7 M. This study provides a sensitive and effective method for the detection of protein in peripheral biofluids, and paves the way for future clinical diagnostics and treatment of disease. Graphical abstract.


Assuntos
Aptâmeros de Nucleotídeos/química , Técnicas Biossensoriais/métodos , Grafite/química , Trombina/análise , Sondas de DNA/química , Técnicas Eletroquímicas/métodos , Ouro/química , Humanos , Ácidos Nucleicos Imobilizados/química , Limite de Detecção , Nanopartículas Metálicas/química , Técnicas de Amplificação de Ácido Nucleico/métodos
12.
Nat Commun ; 11(1): 567, 2020 Jan 28.
Artigo em Inglês | MEDLINE | ID: mdl-31992692

RESUMO

Since the discovery of metal nanoparticles (NPs) in the 1960s, unknown toxicity, cost and the ethical hurdles of research in humans have hindered the translation of these NPs to clinical use. In this work, we demonstrate that Pt NPs with protein coronas are generated in vivo in human blood when a patient is treated with cisplatin. These self-assembled Pt NPs form rapidly, accumulate in tumors, and remain in the body for an extended period of time. Additionally, the Pt NPs are safe for use in humans and can act as anti-cancer agents to inhibit chemotherapy-resistant tumor growth by consuming intracellular glutathione and activating apoptosis. The tumor inhibitory activity is greatly amplified when the Pt NPs are loaded in vitro with the chemotherapeutic drug, daunorubicin, and the formulation is effective even in daunorubicin-resistant models. These in vivo-generated metal NPs represent a biocompatible drug delivery platform for chemotherapy resistant tumor treatment.


Assuntos
Antineoplásicos/sangue , Antineoplásicos/farmacologia , Nanopartículas Metálicas/química , Platina/sangue , Platina/farmacologia , Animais , Apoptose/efeitos dos fármacos , Linhagem Celular Tumoral , Cisplatino/farmacologia , Daunorrubicina/farmacologia , Sistemas de Liberação de Medicamentos , Tolerância a Medicamentos , Feminino , Glutationa/metabolismo , Células Hep G2 , Humanos , Células K562 , Glomérulos Renais/efeitos dos fármacos , Glomérulos Renais/patologia , Masculino , Camundongos , Camundongos Endogâmicos BALB C , Camundongos Endogâmicos C57BL , Camundongos Nus , Tamanho da Partícula , Coroa de Proteína , Fatores de Tempo , Ensaios Antitumorais Modelo de Xenoenxerto , Peixe-Zebra
13.
J Phys Chem Lett ; 11(3): 1178-1188, 2020 Feb 06.
Artigo em Inglês | MEDLINE | ID: mdl-31976669

RESUMO

The lack of long-term stability, the presence of toxic lead, and a low photoluminescence (PL) efficiency are the major obstacles to the commercialization of lead-halide perovskite-based optoelectronic and photovoltaic devices. Herein we report a facile ambient condition doping protocol that addresses all three issues of the CsPbX3 perovskite nanocrystals (NCs) to a substantial extent. We show that the room-temperature treatment of these NCs with MgX2 results in the partial (18-23%) replacement of toxic lead, enhances the PL quantum yield of green-emitting CsPbBr3 (to ∼100% from ∼51%) and violet-emitting CsPbCl3 NCs (to ∼79% from ∼1%), and improves the stability under ambient conditions and in the presence of light and a polar solvent. Ultrafast pump-probe and temperature-dependent PL studies reveal that curing of the intrinsic structural disorder, introduction of some shallow energy levels close to the conduction band edge, and effective passivation of the halide deficiency contribute to the improved properties of the doped systems.


Assuntos
Compostos de Cálcio/química , Magnésio/química , Nanopartículas Metálicas/química , Óxidos/química , Titânio/química , Hexanos/química , Íons/química , Luminescência , Temperatura Ambiente
14.
Nat Commun ; 11(1): 534, 2020 Jan 27.
Artigo em Inglês | MEDLINE | ID: mdl-31988280

RESUMO

A disturbance of reactive oxygen species (ROS) homeostasis may cause the pathogenesis of many diseases. Inspired by natural photosynthesis, this work proposes a photo-driven H2-evolving liposomal nanoplatform (Lip NP) that comprises an upconversion nanoparticle (UCNP) that is conjugated with gold nanoparticles (AuNPs) via a ROS-responsive linker, which is encapsulated inside the liposomal system in which the lipid bilayer embeds chlorophyll a (Chla). The UCNP functions as a transducer, converting NIR light into upconversion luminescence for simultaneous imaging and therapy in situ. Functioning as light-harvesting antennas, AuNPs are used to detect the local concentration of ROS for FRET biosensing, while the Chla activates the photosynthesis of H2 gas to scavenge local excess ROS. The results thus obtained indicate the potential of using the Lip NPs in the analysis of biological tissues, restoring their ROS homeostasis, possibly preventing the initiation and progression of diseases.


Assuntos
Clorofila/metabolismo , Hidrogênio/metabolismo , Lipossomos/metabolismo , Nanopartículas Metálicas/química , Fotossíntese , Espécies Reativas de Oxigênio/metabolismo , Técnicas Biossensoriais , Ouro , Nanoestruturas
15.
J Nanobiotechnology ; 18(1): 18, 2020 Jan 21.
Artigo em Inglês | MEDLINE | ID: mdl-31964403

RESUMO

BACKGROUND: Although accumulating evidence suggests that the crosstalk between malignant cells and cancer-associated fibroblasts (CAFs) actively contributes to tumour growth and metastatic dissemination, therapeutic strategies targeting tumour stroma are still not common in the clinical practice. Metal-based nanomaterials have been shown to exert excellent cytotoxic and anti-cancerous activities, however, their effects on the reactive stroma have never been investigated in details. Thus, using feasible in vitro and in vivo systems to model tumour microenvironment, we tested whether the presence of gold, silver or gold-core silver-shell nanoparticles exerts anti-tumour and metastasis suppressing activities by influencing the tumour-supporting activity of stromal fibroblasts. RESULTS: We found that the presence of gold-core silver-shell hybrid nanomaterials in the tumour microenvironment attenuated the tumour cell-promoting behaviour of CAFs, and this phenomenon led to a prominent attenuation of metastatic dissemination in vivo as well. Mechanistically, transcriptome analysis on tumour-promoting CAFs revealed that silver-based nanomaterials trigger expressional changes in genes related to cancer invasion and tumour metastasis. CONCLUSIONS: Here we report that metal nanoparticles can influence the cancer-promoting activity of tumour stroma by affecting the gene expressional and secretory profiles of stromal fibroblasts and thereby altering their intrinsic crosstalk with malignant cells. This potential of metal nanomaterials should be exploited in multimodal treatment approaches and translated into improved therapeutic outcomes.


Assuntos
Antineoplásicos/química , Fibroblastos Associados a Câncer/efeitos dos fármacos , Nanopartículas Metálicas/química , Metástase Neoplásica/tratamento farmacológico , Ligas/química , Animais , Antineoplásicos/uso terapêutico , Fibroblastos Associados a Câncer/patologia , Linhagem Celular Tumoral , Movimento Celular , Sobrevivência Celular , Progressão da Doença , Doxorrubicina/química , Doxorrubicina/uso terapêutico , Feminino , Fibroblastos/citologia , Fibroblastos/efeitos dos fármacos , Regulação Neoplásica da Expressão Gênica , Ouro/química , Humanos , Nanopartículas Metálicas/uso terapêutico , Camundongos Endogâmicos BALB C , Metástase Neoplásica/patologia , Transplante de Neoplasias , Prata/química , Microambiente Tumoral/efeitos dos fármacos
16.
Dis Aquat Organ ; 137(3): 175-183, 2020 Jan 16.
Artigo em Inglês | MEDLINE | ID: mdl-31942863

RESUMO

Flavobacterial infections are among the causes of fish losses in farms with the emergence of antibiotic-resistant isolates. Silver nanoparticles (AgNPs) are known for their potent antimicrobial activity against different types of bacteria. In this study, we evaluated the antibacterial properties of AgNPs (diameter: 23 nm) against Flavobacterium johnsoniae infection in common carp Cyprinus carpio. The assays included both in vitro and in vivo antibacterial tests in addition to evaluation of cell toxicity effects on the fish cell lines. The in vitro results revealed potent inhibitory effects of AgNPs on the growth of F. johnsoniae with a minimum inhibitory concentration of 34 µg ml-1. Fish cell (epithelioma papulosum cyprini and koi carp fin) viability was 95-100% after exposure to 500 ng ml-1 (and lower concentrations) of AgNPs. In the exposure experiment, mortality rates decreased from 45% in the infected non-treated group to 30 and 15% in the intraperitoneal injection and immersion-treated groups, respectively. Neither of the treated groups showed any clinical signs or histopathological lesions. The single-dose treatment with AgNPs during early infection with F. johnsoniae aided in minimizing fish losses.


Assuntos
Carpas , Nanopartículas Metálicas , Animais , Flavobacterium , Testes de Sensibilidade Microbiana , Prata
17.
Environ Technol ; 41(5): 566-576, 2020 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-30052145

RESUMO

In the present study, a biosensor was developed for the detection of organophosphorous compounds. Core electrode of a working electrode was obtained by depositing the paste of Gold nanoparticles and Multi-walled Carbon Nanotubes on a gold wire. The acetylcholinesterase enzyme was immobilized on carboxylated Single-walled Carbon Nanotubes and pasted onto a core of electrode followed by coating with a nafion layer to prevent enzyme leaching from the electrode. This electrode was further used as a working electrode in the sensor. This sensor worked on the AChE inhibition mechanism where the signal is inversely proportional to the amount of organophosphorous compounds. The electrocatalytic activity of this sensor was observed at a potential of +0.360 mV. The standardized conditions for this sensor were pH at 7.0, temperature at 30°C and response time at less than 10s. The linear working range of this biosensor was 0.1-130 µM with the lowest detection limit (LOD) of 1.9, 2.3, 2.2 and 2.5 nM for Methyl Parathion, Monocrotophos, Chlorpyrifos and Endosulfan, respectively. The biosensor showed excellent reusability (upto 55 times) and can be stored stably for 2 months.


Assuntos
Técnicas Biossensoriais , Nanopartículas Metálicas , Nanotubos de Carbono , Eletrodos , Enzimas Imobilizadas , Polímeros de Fluorcarboneto , Ouro
18.
J Photochem Photobiol B ; 202: 111674, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31778953

RESUMO

The present work showed the preparation of gold (Au NPs) and silver nanoparticles (Ag NPs) using aqueous leaf extract of Clinacanthus nutans Lindau (C. Lindau). The prepared NPs were studied using various microscopic and spectroscopic techniques, which confirmed the formation of crystalline Ag NPs, Au NPs that are stabilized with C. Lindau extract polyphenols. The prepared Au NPs and Ag NPs are studied to assess their comparative analgesic and muscle relaxant activities conducted on BALB/c mice. The muscle relaxant studies displayed that Ag NPs were comparatively higher efficient than Au NPs and methanolic C. Lindau extract in traction examination. Additionally, the analgesic studies exhibited that Ag NPs, Au NPs showed maximum percentage reduction in acetic acid induced writhing at the concentrations of 50, 100 and 150 mg/kg body weight. Further, these results conclude that as prepared Au NPs and Ag NPs prepared from C. Lindau leaf extract demonstrated very good analgesic and muscle relaxant activities for the use of pain management in nursing care.


Assuntos
Acanthaceae/química , Analgésicos/síntese química , Ouro/química , Nanopartículas Metálicas/química , Prata/química , Acanthaceae/metabolismo , Ácido Acético/toxicidade , Analgésicos/farmacologia , Analgésicos/uso terapêutico , Animais , Química Verde , Nanopartículas Metálicas/uso terapêutico , Camundongos , Camundongos Endogâmicos BALB C , Relaxamento Muscular/efeitos dos fármacos , Cuidados de Enfermagem , Dor/induzido quimicamente , Dor/tratamento farmacológico , Manejo da Dor/métodos , Extratos Vegetais/química , Folhas de Planta/química , Folhas de Planta/metabolismo
19.
Water Res ; 169: 115229, 2020 Feb 01.
Artigo em Inglês | MEDLINE | ID: mdl-31783256

RESUMO

Antibiotic resistance in bacteria is a growing threat to global human health. Horizontal gene transfer (HGT) of antibiotic resistance genes (ARGs) is recognized as the primary contributor to antibiotic resistance dissemination. Silver nanoparticles (AgNPs) are widely used in personal care products as antimicrobial agents. While heavy metals are known to induce antibiotic resistance in bacteria, it is not known whether AgNPs in the environment can stimulate the HGT of ARGs. Here, we report that both AgNPs and ionic silver Ag+, at environmentally relevant and sub-lethal concentrations, facilitate the conjugative transfer of plasmid-borne ARGs across bacterial genera (from the donor Escherichia coli K-12 LE392 to the recipient Pseudomonas putida KT2440). The underlying mechanisms of the Ag+- or AgNPs-promoted HGT were unveiled by detecting oxidative stress and cell membrane permeability, combined with genome-wide RNA sequencing and proteomic analyses. It was found that both Ag+ and AgNPs exposure induced various bacterial responses that included reactive oxygen species (ROS) generation, membrane damage and the SOS response. This study exposes the potential ecological risks of environmental levels of AgNPs and Ag+ for promoting the spread of ARGs and highlights concerns regarding the management of nanoparticles and heavy metals.


Assuntos
Escherichia coli K12 , Nanopartículas Metálicas , Antibacterianos , Resistência Microbiana a Medicamentos , Transferência Genética Horizontal , Humanos , Íons , Plasmídeos , Proteômica , Prata
20.
J Photochem Photobiol B ; 202: 111715, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31790882

RESUMO

Biomimetic gold nanoparticles of biological origin have created a significant impact on the field of biomedicine due to the great expectations of its applications. Because of this, the influences of biomimetic gold nanoparticles have been immensely studied, targeting various cancer cells. However, the impact of biomimetic gold nanoparticles against normal non-cancerous cells is scanty, which impose several limitations in their utility. Taking this as a challenge, we in this study report the biomimetic gold nanoparticles from marine seaweed Gelidium pusillum (G. pusillum) to evaluate its cytotoxic and biocompatible ability evidenced by fluorescence-based assays in cultured cells. The gold nanoparticles obtained in the study were spherical shaped with a mean diameter of 12 ± 4.2 nm. The seaweed extract plays a crucial role in stabilizing the gold nanoparticles to avoid aggregation and coalescence. At an IC50 concentration of 43.09 ± 1.6 µgmL-1, the biomimetic gold nanoparticles were found to be toxic to cancerous cells (MDA-MB-231). Whereas, biomimetic gold nanoparticles exhibit significant biocompatibility with human embryonic kidney cells even at a higher concentration of 150 µgmL-1. The morphological based fluorescence assays confirmed the ability of biomimetic gold nanoparticles in inducing apoptosis and thereby kills cancer cells. Altogether, the gold nanoparticles were safe to normal cells and did not show a significant impact. Hence, the novel biomimetic gold nanoparticles hold potential as multifaceted agent and can further be taken up to various biomedical applications.


Assuntos
Materiais Biocompatíveis/química , Ouro/química , Nanopartículas Metálicas/química , Apoptose/efeitos dos fármacos , Materiais Biocompatíveis/síntese química , Materiais Biocompatíveis/farmacologia , Linhagem Celular Tumoral , Química Verde , Células HEK293 , Humanos , Nanopartículas Metálicas/toxicidade , Tamanho da Partícula , Extratos Vegetais/química , Alga Marinha/química , Alga Marinha/metabolismo
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