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1.
Ecotoxicol Environ Saf ; 202: 110924, 2020 Oct 01.
Artigo em Inglês | MEDLINE | ID: mdl-32800211

RESUMO

Fabrication of poly-(N-isopropylmethacrylamide-co-methacrylic acid) [p(NMA)] microgels to be utilized as microreactors to synthesize stable Ag nanoparticles for catalytic reductive degradation of dyes has been addressed in this work. Both p(NMA) microgel and Ag-p(NMA) hybrid microgel systems have been analyzed by Fourier transform infra-red and Dynamic light scattering, Ultraviolet-Visible spectroscopy, X-ray diffraction and Transmission electron microscopy. Catalytic activity of Ag-p(NMA) towards reductive degradation of Congo Red (CR), Methyl Orange (MO) and Alizarin Yellow (AY) was investigated under different operating conditions. Spectrophotometry was employed to check the progress of reaction while the rate constant (kapp) value of degradation reaction was determined under various conditions to optimize reaction parameters for rapid and economical degradation of these dyes. An increase in kapp value was observed by increasing feed content of dye up to a certain value that decreases again by further increment in dye concentration which reflects that catalysis follows Langmuir-Hinshelwood mechanism. A gradual increase in the kapp value was also observed with increasing quantity of hybrid microgel used as a catalyst. By comparing kapp values of degradation of aforementioned dyes, it was found that Ag-p(NMA) hybrid microgel gives better activity for MO dye degradation in comparison to catalytic degradation of CR and AY.


Assuntos
Compostos Azo/química , Nanopartículas Metálicas/química , Prata/química , Catálise , Corantes/química , Vermelho Congo/química , Hidrogéis/química , Microscopia Eletrônica de Transmissão , Polímeros/química , Espectrofotometria , Difração de Raios X
2.
Int J Nanomedicine ; 15: 5027-5042, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32764934

RESUMO

Background: Bactericidal capacity, durable inhibition of biofilm formation, and a three-dimensional (3D) porous structure are the emphases of infected bone defect (IBD) treatment via local scaffold implantation strategy. Purpose: In this study, silver nanoparticle (AgNP)-loaded nano-hydroxyapatite (nHA)@ reduced graphene oxide (RGO) 3D scaffolds (AHRG scaffolds) were designed to alleviate bone infection, inhibit biofilm formation, and promote bone repair through the synergistic effects of AgNPs, RGO, and nHA. Materials and Methods: AHRGs were prepared using a one-step preparation method, to create a 3D porous scaffold to facilitate a uniform distribution of AgNPs and nHA. Methicillin-resistant Staphylococcus aureus (MRSA) was used as a model-resistant bacterium, and the effects of different silver loadings on the antimicrobial activity and cytocompatibility of materials were evaluated. Finally, a rabbit IBD model was used to evaluate the therapeutic effect of the AHRG scaffold in vivo. Results: The results showed successful synthesis of the AHRG scaffold. The ideal 3D porous structure was verified using scanning electron microscopy and transmission electron microscopy, and X-ray photoelectron spectroscopy and selected area electron diffraction measurements revealed uniform distributions of AgNP and nHA. In vitro antibacterial and cytocompatibility indicated that the 4% AHRG scaffolds possessed the most favorable balance of bactericidal properties and cytocompatibility. In vivo evaluation of the IBD model showed promising treatment efficacy of AHRG scaffolds. Conclusion: The as-fabricated AHRG scaffolds effectively eliminated infection and inhibited biofilm formation. IBD repair was facilitated by the bactericidal properties and 3D porous structure of the AHRG scaffold, suggesting its potential in the treatment of IBDs.


Assuntos
Antibacterianos/farmacologia , Doenças Ósseas Infecciosas/terapia , Grafite/química , Nanopartículas Metálicas/química , Engenharia Tecidual/métodos , Tecidos Suporte/química , Animais , Antibacterianos/química , Biofilmes/efeitos dos fármacos , Regeneração Óssea/efeitos dos fármacos , Substitutos Ósseos , Osso e Ossos/efeitos dos fármacos , Modelos Animais de Doenças , Durapatita/química , Feminino , Masculino , Teste de Materiais , Staphylococcus aureus Resistente à Meticilina/efeitos dos fármacos , Porosidade , Coelhos , Ratos , Prata/química , Prata/farmacologia , Infecções Estafilocócicas/terapia
3.
Int J Nanomedicine ; 15: 5459-5471, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32801700

RESUMO

Purpose: Indocyanine green (ICG), a near infrared (NIR) dye clinically approved in medical diagnostics, possesses great heat conversion efficiency, which renders itself as an effective photosensitizer for photothermal therapy (PTT) of cancer. However, there remain bottleneck challenges for use in PTT, which are the poor photo and plasma stability of ICG. To address these problems, in this research, ICG-loaded silver nanoparticles were prepared and evaluated for the applicability as an effective agent for photothermal cancer therapy. Methods and Results: PEGylated bovine serum albumin (BSA)-coated silver core/shell nanoparticles were synthesized with a high loading of ICG ("PEG-BSA-AgNP/ICG"). Physical characterization was carried out using size analyzer, transmission electron microscopy, and Fourier transform infrared spectrophotometry to identify successful preparation and size stability. ICG-loading content and the photothermal conversion efficiency of the particles were confirmed with inductively coupled plasma mass spectrometry and laser instruments. In vitro studies showed that the PEG-BSA-AgNP/ICG could provide great photostability for ICG, and their applicability for PTT was verified from the cellular study results. Furthermore, when the PEG-BSA-AgNP/ICG were tested in vivo, study results exhibited that ICG could stably remain in the blood circulation for a markedly long period (plasma half-life: 112 min), and about 1.7% ID/g tissue could be accumulated in the tumor tissue at 4 h post-injection. Such nanoparticle accumulation in the tumor enabled tumor surface temperature to be risen to 50°C (required for photo-ablation) by laser irradiation and led to successful inhibition of tumor growth in the B16F10 s.c. syngeneic nude mice model, with minimal systemic toxicity. Conclusion: Our findings demonstrated that PEG-BSA-AgNPs could serve as effective carriers for delivering ICG to the tumor tissue with great stability and safety.


Assuntos
Antineoplásicos/farmacologia , Nanopartículas Metálicas/química , Fotoquimioterapia/métodos , Fármacos Fotossensibilizantes/química , Animais , Antineoplásicos/efeitos adversos , Antineoplásicos/farmacocinética , Linhagem Celular Tumoral , Sistemas de Liberação de Medicamentos/métodos , Estabilidade de Medicamentos , Difusão Dinâmica da Luz , Meia-Vida , Humanos , Verde de Indocianina/química , Verde de Indocianina/farmacocinética , Melanoma Experimental/tratamento farmacológico , Camundongos Endogâmicos ICR , Camundongos Nus , Microscopia Eletrônica de Transmissão , Polietilenoglicóis/química , Soroalbumina Bovina/química , Prata/química , Espectroscopia de Infravermelho com Transformada de Fourier
4.
Int J Nanomedicine ; 15: 4969-4990, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32764930

RESUMO

Background: Polyphenols possess antioxidant, anti-inflammatory and antimicrobial properties and have been used in the treatment of skin wounds and burns. We previously showed that tannic acid-modified AgNPs sized >26 nm promote wound healing, while tannic acid-modified AgNPs sized 13 nm can elicit strong local inflammatory response. In this study, we tested bimetallic Au@AgNPs sized 30 nm modified with selected flavonoid and non-flavonoid compounds for wound healing applications. Methods: Bimetallic Au@AgNPs were obtained by growing an Ag layer on AuNPs and further modified with selected polyphenols. After toxicity tests and in vitro scratch assay in HaCaT cells, modified lymph node assay as well as the mouse splint wound model were further used to access the wound healing potential of selected non-toxic modifications. Results: Tannic acid, gallic acid, polydatin, resveratrol, catechin, epicatechin, epigallocatechin, epicatechin gallate, epigallocatechin gallate and procyanidin B2 used to modify Au@AgNPs exhibited good toxicological profiles in HaCaT cells. Au@AgNPs modified with 15 µM tannic acid, 200 µM resveratrol, 200 µM epicatechin gallate, 1000 µM gallic acid and 200 µM procyanidin B2 induced wound healing in vivo and did not lead to the local irritation or inflammation. Tannic acid-modified Au@AgNPs induced epithelial-to-mesenchymal transition (EMT) - like re-epithelialization, while other polyphenol modifications of Au@AgNPs acted through proliferation and wound closure. Conclusion: Bimetallic Au@AgNPs can be used as a basis for modification with selected polyphenols for topical uses. In addition, we have demonstrated that particular polyphenols used to modify bimetallic nanoparticles may show different effects upon different stages of wound healing.


Assuntos
Ouro/química , Nanopartículas Metálicas/química , Polifenóis/química , Polifenóis/farmacologia , Prata/química , Cicatrização/efeitos dos fármacos , Animais , Antioxidantes/química , Antioxidantes/farmacologia , Biflavonoides/química , Catequina/análogos & derivados , Catequina/química , Camundongos , Proantocianidinas/química , Taninos/química
5.
Int J Nanomedicine ; 15: 5147-5163, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32764942

RESUMO

Background: In the last decades, nosocomial infections caused by drug-resistant Pseudomonas aeruginosa became a common problem in healthcare facilities. Antibiotics are becoming less effective as new resistant strains appear. Therefore, the development of novel enhanced activity antibacterial agents becomes very significant. A combination of nanomaterials with different physical and chemical properties enables us to generate novel multi-functional derivatives. In this study, graphene oxide and polyvinylpyrrolidone-stabilized silver nanoparticles hybrid nanocomposite (GO-Ag HN) were synthesized. The relation between antibiotic resistance and GO-Ag HN potential toxicity to clinical P. aeruginosa strains, their antibiotic resistance, and molecular mechanisms were assessed. Methods: Chemical state, particle size distribution, and morphology of synthesized GO-Ag NH were investigated using spectroscopy and microscopy techniques (UV-Vis, FTIR, XPS, TEM, SEM, AFM). Broad-spectrum antibiotic resistance of P. aeruginosa strains was determined using E-test. Antibiotic resistance genes were identified using polymerase chain reaction (PCR). Results: In this study, the toxicity of the GO-Ag NH to the isolated clinical P. aeruginosa strains has been investigated. A high antibiotic resistance level (92%) was found among P. aeruginosa strains. The most prevalent antibiotic resistance gene among tested strains was the AMPC beta-lactamase gene (65.6%). UV-vis, FTIR, and XPS studies confirmed the formation of the silver nanoparticles on the GO nanosheets. The functionalization process occurred through the interaction between Ag nanoparticles, GO, and polyvinylpyrrolidone used for nanoparticle stabilization. SEM analysis revealed that GO nanosheets undergo partial fragmentation during hybrid nanocomposite preparation, which remarkably increases the number of sharp edges and their mediated cutting effect. TEM analysis showed that GO-Ag HN spherical Ag nanoparticles mainly 9-12 nm in size were irregularly precipitated on the GO nanosheet surface. A higher density of Ag NPs was observed in the sheets' wrinkles, corrugations, and sharp edges. This hybrid nanocomposite poses enhanced antibacterial activity against carbapenem-resistant P. aeruginosa strains through a possible synergy between toxicity mechanisms of GO nanosheets and Ag nanoparticles. With incubation time increasing up to 10 minutes, the survival of P. aeruginosa decreased significantly. Conclusion: A graphene oxide and silver nanoparticles hybrid composite has been shown to be a promising material to control nosocomial infections caused by bacteria strains resistant to most antibiotics.


Assuntos
Farmacorresistência Bacteriana/genética , Grafite/química , Grafite/farmacologia , Nanopartículas Metálicas/química , Pseudomonas aeruginosa/efeitos dos fármacos , Pseudomonas aeruginosa/genética , Prata/química , Antibacterianos/química , Antibacterianos/farmacologia , Farmacorresistência Bacteriana/efeitos dos fármacos
6.
Aquat Toxicol ; 227: 105582, 2020 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-32823071

RESUMO

While it is likely that ENPs may occur together with other contaminants in nature, the combined effects of exposure to both ENPs and environmental contaminants are not studied sufficiently. In this study, we investigated the acute and sublethal toxicity of PVP coated silver nanoparticles (AgNP) and ionic silver (Ag+; administered as AgNO3) to the marine copepod Calanus finmarchicus. We further studied effects of single exposures to AgNPs (nominal concentrations: low 15 µg L-1 NPL, high 150 µg L-1 NPH) or Ag+ (60 µg L-1), and effects of co-exposure to AgNPs, Ag+ and the water-soluble fraction (WSF; 100 µg L-1) of a crude oil (AgNP + WSF; Ag++WSF). The gene expression and the activity of antioxidant defense enzymes SOD, CAT and GST, as well as the gene expression of HSP90 and CYP330A1 were determined as sublethal endpoints. Results show that Ag+ was more acutely toxic compared to AgNPs, with 96 h LC50 concentrations of 403 µg L-1 for AgNPs, and 147 µg L-1 for Ag+. Organismal uptake of Ag following exposure was similar for AgNP and Ag+, and was not significantly different when co-exposed to WSF. Exposure to AgNPs alone caused increases in gene expressions of GST and SOD, whereas WSF exposure caused an induction in SOD. Responses in enzyme activities were generally low, with significant effects observed only on SOD activity in NPL and WSF exposures and on GST activity in NPL and NPH exposures. Combined AgNP and WSF exposures caused slightly altered responses in expression of SOD, GST and CYP330A1 genes compared to the single exposures of either AgNPs or WSF. However, there was no clear pattern of cumulative effects caused by co-exposures of AgNPs and WSF. The present study indicates that the exposure to AgNPs, Ag+, and to a lesser degree WSF cause an oxidative stress response in C. finmarchicus, which was slightly, but mostly not significantly altered in combined exposures. This indicated that the combined effects between Ag and WSF are relatively limited, at least with regard to oxidative stress.


Assuntos
Copépodes/efeitos dos fármacos , Nanopartículas Metálicas/toxicidade , Estresse Oxidativo/efeitos dos fármacos , Petróleo/toxicidade , Prata/toxicidade , Poluentes Químicos da Água/toxicidade , Animais , Antioxidantes/metabolismo , Copépodes/genética , Copépodes/metabolismo , Interações Medicamentosas , Expressão Gênica/efeitos dos fármacos , Íons , Nanopartículas Metálicas/química , Estresse Oxidativo/genética , Água do Mar/química , Prata/química , Solubilidade , Testes de Toxicidade Aguda , Testes de Toxicidade Subaguda , Poluentes Químicos da Água/química
7.
Int J Nanomedicine ; 15: 5345-5360, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32801693

RESUMO

Background: Soft corals have been endorsed as a plentiful source of bioactive compounds with promising anti-inflammatory activities; therefore, exploring their potential as source of anti-inflammatory metabolites has stimulated a growing research interest. Purpose: To investigate the anti-inflammatory potential of the soft coral, Nephthea sp., in its bulk and silver nanostructure. Metabolomics analysis of Nephthea sp., followed by molecular docking studies, was also conducted in order to explore and predict the secondary metabolites that might provide its inhibitory actions on inflammation. Materials and Methods: The petroleum ether and ethyl acetate fractions were used to synthesize silver nanoparticles. The prepared silver nanoparticles were characterized through UV-vis spectrophotometric, transmission electron microscopy (TEM) and Fourier-transform infrared spectroscopy (FTIR) analyses. Testing for the anti-inflammatory activity was performed against COX-1 and COX-2. Furthermore, liquid chromatography-mass spectrometry (LC-MS) based metabolomics analysis and molecular docking were also applied. Results: A variety of secondary metabolites were identified, among them, sesquiterpenes were found to prevail. The petroleum ether and acetone fractions of Nephthea sp. showed the highest COX-2 inhibitory activities, possibly attributable to their substantial contents of terpenoids. Additionally, the green synthesized silver nanoparticles of both the petroleum ether and ethyl acetate fractions of Nephthea sp. demonstrated higher anti-COX-2 properties. Conclusion: The obtained results showed the effectiveness of non-targeted metabolomics technique in metabolic profiling of Nephthea sp., helping the search for new bioactive metabolites in future chemical studies on this soft coral. The interesting anti-inflammatory potential of the tested extracts and their nanoparticles could also be relevant to the development of new, effective anti-inflammatory agents.


Assuntos
Antozoários/metabolismo , Anti-Inflamatórios/química , Anti-Inflamatórios/farmacologia , Nanopartículas Metálicas/química , Prata/química , Alcanos/química , Animais , Antozoários/química , Anti-Inflamatórios/síntese química , Ciclo-Oxigenase 1/química , Ciclo-Oxigenase 1/metabolismo , Inibidores de Ciclo-Oxigenase 2/química , Inibidores de Ciclo-Oxigenase 2/farmacologia , Inibidores de Ciclo-Oxigenase/química , Inibidores de Ciclo-Oxigenase/farmacologia , Química Verde , Humanos , Metabolômica , Simulação de Acoplamento Molecular , Metabolismo Secundário , Sesquiterpenos/análise , Espectrometria de Massas por Ionização por Electrospray , Espectroscopia de Infravermelho com Transformada de Fourier
8.
Ecotoxicol Environ Saf ; 203: 110995, 2020 Oct 15.
Artigo em Inglês | MEDLINE | ID: mdl-32678763

RESUMO

In the present study, silver (Ag) atoms were chemically deposited on γ-alumina (Al2O3) nanospheres to be further functionalized with trithiocyanuric acid (TTC). The result was Al2O3@Ag@TTC composites, which were used for the selective extraction and preconcentration of Fe (III) and Pb (II) ions in seawater and river water samples. TTC is a potent scavenger of heavy metal ions with multiple nitrogen- and sulfur-containing functional groups. The concentrations of analytes were determined by flame atomic absorption spectrometry, and the structure of the synthetic adsorbent was characterized by spectral and microscopic techniques. Furthermore, the fundamental parameters influencing the extraction and desorption of the target ions were evaluated. Under optimized conditions, the calibration curve was linear in the range of 10-100 ng mL-1 for both analytes. The detection limits of the proposed method for Fe (III) and Pb (II) ions were 1.5 ng mL-1 and 0.8 ng mL-1, respectively, with a relative standard deviation of less than 6.1% (n = 7). Moreover, the proposed method tolerated salinities of up to 50.0 g L-1 without exhibiting any decrease in selectivity or recovery. The developed method was successfully applied to extract Fe (III) and Pb (II) ions from seawater and river water samples. The extraction recovery rates of the spiked ions were at least 93% for Fe (III) and 97 % for Pb (II).


Assuntos
Óxido de Alumínio/química , Ferro/análise , Chumbo/análise , Nanoconjugados/química , Prata/química , Triazinas/química , Poluentes Químicos da Água/análise , Água Doce/química , Concentração de Íons de Hidrogênio , Íons , Água do Mar/química , Extração em Fase Sólida/métodos
9.
Food Chem ; 332: 127346, 2020 Dec 01.
Artigo em Inglês | MEDLINE | ID: mdl-32619938

RESUMO

Fiber optic surface plasmon resonance (SPR) sensor utilizing silver (Ag) and Ag-graphene oxide (GO) is designed and developed for the detection of adulteration of glucose and fructose in pure honey. The concentration range of the two adulterants in pure honey is varied from 4% to 20% with a step change of 4%. The experiments were performed with two different fiber optic probes viz. Probe 1 and Probe 2. Probe 1 is fabricated by coating 50 nm Ag film on unclad optical fiber portion and Probe 2 is fabricated by modifying Ag film with GO for sensitivity improvement. The study confirms that using GO modified fiber optic probe, the sensitivity is enhanced to 24% and 37% for glucose and fructose adulterated honey samples respectively. The technique presented in this study is easy, rapid, label free and shows high prospective for the detection of adulterants in pure honey.


Assuntos
Grafite/química , Mel/análise , Fibras Ópticas , Prata/química , Ressonância de Plasmônio de Superfície/instrumentação
10.
Artigo em Inglês | MEDLINE | ID: mdl-32614255

RESUMO

Recently, Silver nanoparticles (AgNPs) have become widely applied nanomaterial in human contacting areas such as cosmetics, food and medicine due to their antibacterial property. On the other hand, surfactants are essential ingredient of several industrial and consumer formulations. Based on these important applications, the current research was aimed to carry out the synthesis and characterization of Tween 80 capped silver nanoparticles (T80-AgNPs) using gamma radiation reduction method. Characterization of T80-AgNPs was occurred by using UV-Vis, XRD, FTIR and TEM techniques. UV-Visible spectra showed surface plasmon resonance (SPR) peak in the range of 420 nm signifying the synthesis of colloidal AgNPs. TEM confirmed the formation of spherical and uniformly distributed AgNPs with average size of 18 nm. XRD analysis illustrated the formation of pure crystalline AgNPs. The FTIR analysis provides evidence for the stabilization of AgNPs by Tween 80. The synthesized T80-AgNPs were evaluated for antibacterial activity against both Escherichia coli (E. coli) as gram negative (G -ve) bacteria and Staphylococcus aureus (S. aureus) as gram positive (G + ve) bacteria and anti-biofilm activity to P. aeruginosa. The results show that T80-AgNPs exhibits excellent antibacterial and antibiofilm activities.


Assuntos
Antibacterianos/química , Antibacterianos/farmacologia , Raios gama , Nanopartículas Metálicas/química , Polissorbatos/química , Prata/química , Biofilmes/efeitos dos fármacos , Escherichia coli/efeitos dos fármacos , Humanos , Testes de Sensibilidade Microbiana , Pseudomonas aeruginosa/efeitos dos fármacos , Prata/farmacologia , Nitrato de Prata/química , Staphylococcus aureus/efeitos dos fármacos
11.
Int J Nanomedicine ; 15: 3405-3414, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32523340

RESUMO

Background: Fluorescent metallic nanodots (NDs) have become a promising nanoprobe for a wide range of biomedical applications. Because Ag NDs have a high tendency to be oxidized, their synthesis and storage are a big challenge. Thus, the method for preparing stable Ag NDs is urgently needed. Surface modification and functionalization can enrich the capability of Ag NDs. Methods: In this work, fluorescent Ag NDs were synthesized in deoxygenated water by using porcine pancreatic α-amylase (PPA) as the stabilizing/capping agent. The absorption and fluorescence of PPA-protected Ag NDs (PPA@AgNDs) were measured with a spectrophotometer and a spectrofluorometer, respectively. The morphology of PPA@AgNDs was characterized by high-angle annular dark-field (HAADF) scanning transmission electron microscopy (STEM). The biocompatibility of PPA@AgNDs was evaluated by tetrazolium (MTT)-based assay. PolyLys-Cys-SH (sequence: KKKKKKC) peptides were conjugated to PPA@AgNDs via heterobifunctional crosslinkers. PolyLys-Cys-linked PPA@AgNDs absorbed 5-aminolevulinic acid (ALA) by electrostatic interaction at physiological pH. The capability of tumor targeting was evaluated by intravenously injecting PPA@AgND-ALA into 4T1 breast cancer xenograft mouse models. Photodynamic therapy (PDT) against tumors was performed under 635 nm laser irradiation. Results: PPA@AgNDs emitted at 640 nm with quantum yield of 2.1%. The Ag NDs exhibited strong photostability over a long period and a fluorescence lifetime of 5.1 ns. PPA@AgNDs easily entered the cells to stain the nuclei, showing the capabilities of living cell imaging with negligible cytotoxicity. ALA-loaded PPA@AgNDs (PPA@AgND-ALA) presented the superiority of passive tumor targeting via the enhanced permeability and retention (EPR) effect. Tumors were visualized in the near-infrared (NIR) region with reduced background noise. ALA molecules released from PPA@AgND-ALA was converted into the photosensitizer (PS) of protoporphyrin IX (PpIX) intracellularly and intratumorally, which greatly improved the PDT efficacy. Conclusion: Our approach opens a new way to design a novel theranostic nanoplatform of PPA@AgND-ALA for effective tumor targeting and fluorescence image-guided PDT.


Assuntos
Amilases/metabolismo , Nanopartículas/química , Neoplasias/tratamento farmacológico , Imagem Óptica , Fotoquimioterapia , Prata/química , Animais , Linhagem Celular Tumoral , Fluorescência , Humanos , Ácidos Levulínicos/farmacologia , Camundongos , Tamanho da Partícula , Espectrofotometria Ultravioleta , Suínos , Nanomedicina Teranóstica , Ensaios Antitumorais Modelo de Xenoenxerto
12.
Chemosphere ; 257: 127123, 2020 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-32505037

RESUMO

It is a central issue to improve the separation efficiency of photogenerated charge carriers and the utilization of visible light in the field of photocatalysis. Herein, taking MIL-125(Ti) as a host material, the Pt/MIL-125(Ti) was first prepared by solvothermal method to build the interface of Schottky junction. Ag was then introduced onto the surface of Pt/MIL-125(Ti) to form the interface with the surface plasmon resonance effect. These double interfaces in the composite play a synergistic role on the photodagradation. The morphology, crystallinity and photochemical properties of the material were tested. By comparison, Pt/MIL-125(Ti)/Ag (4 wt% Ag) exhibited the best performance in the photodegradation of ketoprofen (KP, 10 mg/L) and the degradation process conformed to the pseudo-first-order kinetics. The photodegradation rate is 0.0253 min-1, which was higher than MIL-125(Ti) (0.0009 min-1). The TOC removal efficiency of KP reached approximately 51.5%. The electron paramagnetic resonance (EPR) and free radical capture tests verified that h+ and ·OH played the prominent roles during the reaction system. The degradation process, possible pathways and reaction mechanism were proposed. The design of the double interfaces between semiconductor and noble metals is a novel strategy to enhance the photocatalytic performance.


Assuntos
Cetoprofeno/química , Modelos Químicos , Catálise , Luz , Dietilamida do Ácido Lisérgico/análogos & derivados , Fotólise , Semicondutores , Prata/química , Titânio/química
13.
Int J Nanomedicine ; 15: 3921-3936, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32581537

RESUMO

Background: Mesoporous calcium-silicate nanoparticles (MCSNs) have good prospects in the medical field due to their great physicochemical characteristics, antibacterial activity and drug delivery capacity. This study was to analyze the antibiofilm activity and mechanisms of silver (Ag) and zinc (Zn) incorporated MCSNs (Ag/Zn-MCSNs) with different percentages of Ag and Zn. Methods: Ag/Zn(1:9, molar ratio)-MCSNs and Ag/Zn(9:1, molar ratio)-MCSNs were prepared and characterized. Endocytosis of nanoparticles by Enterococcus faecalis (E. faecalis) treated with Ag/Zn-MCSNs was observed using TEM to explore the antibacterial mechanisms. The antibiofilm activity of Ag/Zn-MCSNs with different ratios of Ag and Zn was tested by E. faecalis biofilm model in human roots. The human roots pretreated by different Ag/Zn-MCSNs were cultured with E. faecalis. Then, SEM and CLSM were used to observe the survival of E. faecalis on the root canal wall. Cytotoxicity of the nanoparticles was tested by CCK8 kits. Results: The Ag/Zn-MCSNs release Ag+ and destroy the cell membranes to kill bacteria. The MCSNs containing Ag showed antibacterial activity against E. faecalis biofilms in different degrees, and they can adhere to dentin surfaces to get a continuous antibacterial effect. However, MTA, MCSNs and Zn-MCSNs could not disrupt the bacterial biofilms obviously. MCSNs, Ag/Zn(1:1, molar ratio)-MCSNs and Ag/Zn(1:9)-MCSNs showed no obvious cytotoxicity, while Ag-MCSNs and Ag/Zn(9:1)-MCSNs showed cytotoxicity. Zn-MCSNs can slightly promote cell proliferation. Conclusion: Ag/Zn-MCSNs have good antibiofilm activity. They might achieve an appropriate balance between the antibacterial activity and cytotoxicity by adjusting the ratio of Ag and Zn. Ag/Zn-MCSNs are expected to be a new type of root canal disinfectant or sealer for root canal treatment.


Assuntos
Antibacterianos/farmacologia , Enterococcus faecalis/efeitos dos fármacos , Nanopartículas/química , Prata/química , Zinco/química , Animais , Antibacterianos/química , Biofilmes/efeitos dos fármacos , Compostos de Cálcio/química , Cavidade Pulpar/microbiologia , Dentina/efeitos dos fármacos , Endocitose/efeitos dos fármacos , Enterococcus faecalis/fisiologia , Infecções por Bactérias Gram-Positivas/prevenção & controle , Humanos , Camundongos , Osteoblastos/efeitos dos fármacos , Porosidade , Silicatos/química , Prata/farmacologia , Zinco/farmacologia
14.
Chemosphere ; 257: 127236, 2020 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-32512333

RESUMO

Nowadays, air pollution has become a global menace being responsible of a significant increase on the morbidity and mortality of human beings. In view of this, sustainable and efficient technologies for air purification are being sought. Air purification by photocatalytic treatment has received a lot of attention due to the unspecific and high oxidation capacity of the catalyst; however still some variables must be optimized to assure practical applications. In this work, visible light active TiO2-Cu2+@perlite and Ag@TiO2-Cu2+/perlite supported materials were fabricated. TiO2-Cu2+ (2 at. %) were synthesized using a sol-gel procedure followed of the impregnation of the support by immersion. For Ag@TiO2-Cu2+, silver deposition was conducted by chemical reduction using sodium citrate and sodium borohydride. The materials (powders and supported materials) were characterized by Scanning Electron Microscopy (SEM) to demonstrate their small size and adherence to the substrate. A prototype of a photocatalytic air purifier was built. The efficacy of the prototype was evaluated for the disinfection of indoor air (dentistry clinics). The photo-catalyst was activated using visible and UVA low-cost high-energy LEDs. The antibacterial activity of the air filter was evaluated. Ag@TiO2-Cu2+ exerts better air disinfection activity at lower doses in comparison to TiO2-Cu2+. Bacterial growth inhibitions up to 99% were achieved for both, Gram-negative and Gram-positive bacteria. The incorporation of Ag and Cu to TiO2 improves the antibacterial activity of the materials due to enhanced photocatalytic activity and the synergic activity of TiO2 and dopant elements (Ag, Cu) to inhibit microorganism's growth.


Assuntos
Filtros de Ar , Antibacterianos/química , Catálise , Desinfecção/métodos , Luz , Microscopia Eletrônica de Varredura , Prata/química , Titânio/química
15.
Food Chem ; 328: 127106, 2020 Oct 30.
Artigo em Inglês | MEDLINE | ID: mdl-32485584

RESUMO

In this work, based on the strawberry-like SiO2/Ag nanocomposites (SANC) immersed filter paper, a newly surface-enhanced Raman scattering (SERS) substrate was constructed for the detection of acrylamide (AAm) in food products. To construct filter paper-based SANC (F-SANC) SERS substrates, SiO2 nanoparticles (SNP) were firstly synthesized and acted as carriers. After that, the in-situ preparation of silver nanoparticles (Ag NP) on SNP surface was carried out to form the strawberry-like three-dimensional (3D) structure of SANC. Finally, SANC were entangled into the filter paper to produce nanoarchitecture, thus providing enhanced plasmon resonance between SANC with strong SERS signal. Under the optimized conditions, the method exhibited good performance toward AAm with a vast linear response from 0.1 nM to 50 µM (R = 0.9935), limit of detection (LOD) of 0.02 nM (S/N = 3), and the recoveries of 80.5%~105.6% for practical samples. This strategy showed good robustness in the rapid and sensitive detection of AAm, which could be a promising strategy in food analysis and verification.


Assuntos
Acrilamida/análise , Análise de Alimentos/métodos , Nanopartículas Metálicas/química , Nanocompostos/química , Análise Espectral Raman/métodos , Filtração/instrumentação , Análise de Alimentos/instrumentação , Fragaria/química , Limite de Detecção , Dióxido de Silício/química , Prata/química
16.
ACS Nano ; 14(7): 8846-8854, 2020 07 28.
Artigo em Inglês | MEDLINE | ID: mdl-32578981

RESUMO

The COVID-19 pandemic is endangering the world due to the spread of respiration droplets with viruses. Medical workers and frontline staff need to wear respirators to protect themselves from breathing in the virus-containing respiration droplets. The most frequently used state-of-the-art respirators are of N95 standard; however, they lack self-decontamination capabilities. In addition, the viruses and bacteria can accumulate on the respirator surfaces, possessing high risks to the wearers over long-term usage. Photothermal decontamination is a contactless, fast, low-cost, and widely available method, capable of decontaminating the respirators. Herein, we report a plasmonic photothermal and superhydrophobic coating on N95 respirators, possessing significantly better protection than existing personal protection equipment. The plasmonic heating can raise the surface temperature to over 80 °C for this type of respirator within 1 min of sunlight illumination. The superhydrophobic features prohibit respiration droplets from accumulating on the respirator surfaces. The presence of the silver nanoparticles can provide additional protection via the silver ion's disinfection toward microbes. These synergistic features of the composite coatings provide the N95 respirator with better protection and can inspire experts from interdisciplinary fields to develop better personal protection equipment to fight the COVID-19 pandemic.


Assuntos
Desinfecção/métodos , Desenho de Equipamento/métodos , Máscaras/normas , Equipamento de Proteção Individual/normas , Impressão Tridimensional , Dispositivos de Proteção Respiratória/normas , Infecções por Coronavirus/prevenção & controle , Desenho de Equipamento/instrumentação , Temperatura Alta , Humanos , Interações Hidrofóbicas e Hidrofílicas , Lasers , Máscaras/virologia , Nanopartículas Metálicas/química , Pandemias/prevenção & controle , Equipamento de Proteção Individual/virologia , Pneumonia Viral/prevenção & controle , Resinas Sintéticas/química , Dispositivos de Proteção Respiratória/virologia , Prata/química , Luz Solar
17.
Nanotoxicology ; 14(7): 908-928, 2020 09.
Artigo em Inglês | MEDLINE | ID: mdl-32574512

RESUMO

Silver nanoparticles (AgNP) are used in multiple applications but primarily in the manufacturing of antimicrobial products. Previous studies have identified AgNP toxicity in airway epithelial cells, but no in vitro studies to date have used organotypic cultures as a high-content in vitro model of the conducting airway to characterize the effects of interactions between host genetic and acquired factors, or gene × phenotype interactions (G × P), on AgNP toxicity. In the present study, we derived organotypic cultures from primary murine tracheal epithelial cells (MTEC) to characterize nominal and dosimetric dose-response relationships for AgNPs with a gold core on barrier dysfunction, glutathione (GSH) depletion, reactive oxygen species (ROS) production, lipid peroxidation, and cytotoxicity across two genotypes (A/J and C57BL/6J mice), two phenotypes ('Normal' and 'Type 2 [T2]-Skewed'), and two exposures (an acute exposure of 24 h and a subacute exposure of 4 h, every other day, over 5 days [5 × 4 h]). We characterized the 'T2-Skewed' phenotype as an in vitro model of chronic respiratory diseases, which was marked by increased sensitivity to AgNP-induced barrier dysfunction, GSH depletion, ROS production, lipid peroxidation, and cytotoxicity, suggesting that asthmatics are a sensitive population to AgNP exposures in occupational settings. This also suggests that exposure limits, which should be based upon the most sensitive population, should be derived using in vitro and in vivo models of chronic respiratory diseases. This study highlights the importance of considering dosimetry as well as G × P effects when screening and prioritizing potential respiratory toxicants. Such in vitro studies can be used to inform regulatory policy aimed at special protections for all populations.


Assuntos
Antibacterianos/toxicidade , Células Epiteliais/efeitos dos fármacos , Nanopartículas Metálicas/toxicidade , Prata/toxicidade , Traqueia/efeitos dos fármacos , Animais , Antibacterianos/química , Técnicas de Cultura de Células , Relação Dose-Resposta a Droga , Células Epiteliais/metabolismo , Células Epiteliais/patologia , Genótipo , Glutationa/metabolismo , Ouro/química , Ouro/toxicidade , Peroxidação de Lipídeos/efeitos dos fármacos , Nanopartículas Metálicas/química , Camundongos , Camundongos Endogâmicos C57BL , Fenótipo , Espécies Reativas de Oxigênio/metabolismo , Prata/química , Propriedades de Superfície , Traqueia/metabolismo , Traqueia/patologia
18.
Food Chem ; 330: 127172, 2020 Nov 15.
Artigo em Inglês | MEDLINE | ID: mdl-32531634

RESUMO

This study demonstrates the development of biocompatible Ag nanoparticles/Tannic acid/Zein electrospun membranes with synergistic antibacterial, catalytic and antioxidant activity. The optimal spinning concentration of zein was 32 wt%. The prepared zein electrospun membranes were immersed into tannic acid (TA) solution to investigate the effects of TA concentrations, pH, temperature and time on the loading amount of TA. Then, the TA/Zein electrospun membranes were immersed into a silver nitrate solution to reduce the AgNPs in situ. The morphology of the electrospun membranes was characterized by scanning electron microscopy (SEM). UV-visible spectrophotometer, Fourier-transform infrared spectroscopy (FT-IR) and X-ray diffraction (XRD) were used to carry out the loading amount of TA and Ag nanoparticles (AgNPs). Finally, the antioxidant, antibacterial and catalytic activity of TA/Zein and AgNPs/TA/Zein electrospun membranes were studied. It was found that the AgNPs/TA/Zein electrospun membranes with different TA concentrations have certain antibacterial, antioxidation and catalytic ability, which may be of interest for the development of active packaging that could extend the shelf life of perishable foods.


Assuntos
Antibacterianos/química , Antioxidantes/química , Nanopartículas Metálicas/química , Prata/química , Soja/química , Taninos/química , Zeína/química , Antibacterianos/farmacologia , Catálise , Escherichia coli/efeitos dos fármacos , Staphylococcus aureus/efeitos dos fármacos
19.
Chemosphere ; 258: 127349, 2020 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-32540544

RESUMO

The current understanding of the biological impacts of silver nanoparticles (AgNPs) is restricted to the direct interactions of the particles with biota. Very little is known about their intracellular fate and subsequent toxic consequences. In this research we investigated the uptake, internal fate (i,e., Ag subcellular partitioning and chemical forms), and phytotoxicity of AgNPs in lettuce following foliar versus root exposure. At the same AgNP exposure concentrations, root exposure led to more deleterious effects than foliar exposure as evidenced by a larger extent of reduced plant biomass, elevated oxidative damage, as well as a higher amount of ultrastructural injuries, despite foliar exposure leading to 2.6-7.6 times more Ag bioaccumulation. Both Ag subcellular partitioning and chemical forms present within the plant appeared to elucidate this difference in toxicity. Following foliar exposure, high Ag in biologically detoxified metals pool (29.2-53.0% by foliar exposure vs. 12.8-45.4% by root exposure) and low Ag proportion in inorganic form (6.1-11.9% vs. 14.1-19.8%) potentially associated with AgNPs tolerance. Silver-containing NPs (24.8-38.6 nm, 1.5-2.3 times larger than the initial size) were detected in lettuce plants exposed to NPs and to dissolved Ag+, suggesting possible transformation and/or aggregation of AgNPs in the plants. Our observations show that the exposure pathway significantly affects the uptake and internal fate of AgNPs, and thus the associated phytotoxicity. The results are an important contribution to improve risk assessment of NPs, and will be critical to ensure food security.


Assuntos
Alface/fisiologia , Nanopartículas Metálicas/toxicidade , Poluentes do Solo/toxicidade , Biomassa , Alface/efeitos dos fármacos , Nanopartículas Metálicas/química , Prata/química , Poluentes do Solo/química
20.
Chemosphere ; 258: 127355, 2020 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-32554015

RESUMO

Three-dimensional Ag(I)-fullerene hybrid microcrystal is fabricated by AgNO3 assisted liquid-liquid interfacial precipitation, containing the abundant sp2-π-electron system. With a mild chemical reduction, it produces the massive Ag nanocluster/fullerene junctions, on which fullerene doubles role as the excellent electron acceptor and photon scavenger, enabling the Plasmon-driven catalytic reaction. Ag nanocluster employed alone could not perform this photocatalytic reaction, neither of fullerene (C60) crystal. It implicates that Ag-fullerene interface is a key to drive catalytic process. Relative to conventional TiO2 nanostructures, fullerene expands light absorption to most solar wavelength and possesses a tightened bandgap which intrinsically expedites the charge transfer and charge separation from coinage metals. Demonstrated by photodegradation of organic molecules, this Ag(I)-fullerene (C60) composite, consisted of a plethora of electron donor-acceptor dyads renders an additional member to photocatalyst family, potentially implemented for photo-electron conversion, water remedy and beyond.


Assuntos
Fulerenos/química , Nanopartículas Metálicas/química , Fotólise , Catálise , Luz , Nanoestruturas/química , Prata/química , Luz Solar , Água
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