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1.
Molecules ; 26(5)2021 Feb 24.
Artigo em Inglês | MEDLINE | ID: mdl-33668169

RESUMO

A series of fifteen silver (I) quinoline complexes Q1-Q15 have been synthesized and studied for their biological activities. Q1-Q15 were synthesized from the reactions of quinolinyl Schiff base derivatives L1-L5 (obtained by condensing 2-quinolinecarboxaldehyde with various aniline derivatives) with AgNO3, AgClO4 and AgCF3SO3. Q1-Q15 were characterized by various spectroscopic techniques and the structures of [Ag(L1)2]NO3Q1, [Ag(L1)2]ClO4Q6, [Ag(L2)2]ClO4Q7, [Ag(L2)2]CF3SO3Q12 and [Ag(L4)2]CF3SO3Q14 were unequivocally determined by single crystal X-ray diffraction analysis. In vitro antimicrobial tests against Gram-positive and Gram-negative bacteria revealed the influence of structure and anion on the complexes' moderate to excellent antibacterial activity. In vitro antioxidant activities of the complexes showed their good radical scavenging activity in ferric reducing antioxidant power (FRAP). Complexes with the fluorine substituent or the thiophene or benzothiazole moieties are more potent with IC50 between 0.95 and 2.22 mg/mL than the standard used, ascorbic acid (2.68 mg/mL). The compounds showed a strong binding affinity with calf thymus-DNA via an intercalation mode and protein through a static quenching mechanism. Cytotoxicity activity was examined against three carcinoma cell lines (HELA, MDA-MB231, and SHSY5Y). [Ag(L2)2]ClO4Q7 with a benzothiazole moiety and [Ag(L4)2]ClO4Q9 with a methyl substituent had excellent cytotoxicity against HELA cells.


Assuntos
Antibacterianos/farmacologia , Antineoplásicos/farmacologia , Antioxidantes/farmacologia , Complexos de Coordenação/farmacologia , DNA/química , Antibacterianos/síntese química , Antibacterianos/química , Antineoplásicos/síntese química , Antineoplásicos/química , Antioxidantes/síntese química , Antioxidantes/química , Linhagem Celular Tumoral , Proliferação de Células/efeitos dos fármacos , Complexos de Coordenação/síntese química , Complexos de Coordenação/química , Ensaios de Seleção de Medicamentos Antitumorais , Compostos Férricos/antagonistas & inibidores , Bactérias Gram-Negativas/efeitos dos fármacos , Bactérias Gram-Positivas/efeitos dos fármacos , Humanos , Testes de Sensibilidade Microbiana , Oxirredução , Quinolinas/química , Quinolinas/farmacologia , Bases de Schiff/química , Bases de Schiff/farmacologia , Prata/química , Prata/farmacologia
2.
Molecules ; 26(4)2021 Feb 14.
Artigo em Inglês | MEDLINE | ID: mdl-33672903

RESUMO

Burkholderia pseudomallei is the causative pathogen of melioidosis and this bacterium is resistant to several antibiotics. Silver nanoparticles (AgNPs) are an interesting agent to develop to solve this bacterial resistance. Here, we characterize and assess the antimelioidosis activity of AgNPs against these pathogenic bacteria. AgNPs were characterized and displayed a maximum absorption band at 420 nm with a spherical shape, being well-monodispersed and having high stability in solution. The average size of AgNPs is 7.99 ± 1.46 nm. The antibacterial efficacy of AgNPs was evaluated by broth microdilution. The bactericidal effect of AgNPs was further assessed by time-kill kinetics assay. Moreover, the effect of AgNPs on the inhibition of the established biofilm was investigated by the crystal violet method. In parallel, a study of the resistance induction development of B. pseudomallei towards AgNPs with efflux pump inhibiting effect was performed. We first found that AgNPs had strong antibacterial activity against both susceptible and ceftazidime-resistant (CAZ-resistant) strains, as well as being efficiently active against B. pseudomallei CAZ-resistant strains with a fast-killing mode via a bactericidal effect within 30 min. These AgNPs did not only kill planktonic bacteria in broth conditions, but also in established biofilm. Our findings first documented that the resistance development was not induced in B. pseudomallei toward AgNPs in the 30th passage. We found that AgNPs still showed an effective efflux pump inhibiting effect against these bacteria after prolonged exposure to AgNPs at sublethal concentrations. Thus, AgNPs have valuable properties for being a potent antimicrobial agent to solve the antibiotic resistance problem in pathogens.


Assuntos
Proteínas de Bactérias/antagonistas & inibidores , Burkholderia pseudomallei/fisiologia , Melioidose/tratamento farmacológico , Melioidose/microbiologia , Nanopartículas Metálicas/uso terapêutico , Prata/uso terapêutico , Taninos/uso terapêutico , Antibacterianos/farmacologia , Antibacterianos/uso terapêutico , Proteínas de Bactérias/metabolismo , Burkholderia pseudomallei/efeitos dos fármacos , Ceftazidima/farmacologia , Ceftazidima/uso terapêutico , Farmacorresistência Bacteriana/efeitos dos fármacos , Difusão Dinâmica da Luz , Cinética , Nanopartículas Metálicas/ultraestrutura , Testes de Sensibilidade Microbiana , Viabilidade Microbiana/efeitos dos fármacos , Fenótipo , Prata/farmacologia , Eletricidade Estática , Taninos/farmacologia
3.
Bone Joint J ; 103-B(3): 423-429, 2021 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-33641432

RESUMO

Periprosthetic joint infection (PJI) is one of the most dreaded complications after arthroplasty surgery; thus numerous approaches have been undertaken to equip metal surfaces with antibacterial properties. Due to its antimicrobial effects, silver is a promising coating for metallic surfaces, and several types of silver-coated arthroplasty implants are in clinical use today. However, silver can also exert toxic effects on eukaryotic cells both in the immediate vicinity of the coated implants and systemically. In most clinically-used implants, silver coatings are applied on bulk components that are not in direct contact with bone, such as in partial or total long bone arthroplasties used in tumour or complex revision surgery. These implants differ considerably in the coating method, total silver content, and silver release rates. Safety issues, such as the occurrence of argyria, have been a cause for concern, and the efficacy of silver coatings in terms of preventing PJI is also controversial. The application of silver coatings is uncommon on parts of implants intended for cementless fixation in host bone, but this option might be highly desirable since the modification of implant surfaces in order to improve osteoconductivity can also increase bacterial adhesion. Therefore, an optimal silver content that inhibits bacterial colonization while maintaining osteoconductivity is crucial if silver were to be applied as a coating on parts intended for bone contact. This review summarizes the different methods used to apply silver coatings to arthroplasty components, with a focus on the amount and duration of silver release from the different coatings; the available experience with silver-coated implants that are in clinical use today; and future strategies to balance the effects of silver on bacteria and eukaryotic cells, and to develop silver-coated titanium components suitable for bone ingrowth. Cite this article: Bone Joint J 2021;103-B(3):423-429.


Assuntos
Antibacterianos/farmacologia , Artroplastia , Materiais Revestidos Biocompatíveis/farmacologia , Próteses e Implantes , Infecções Relacionadas à Prótese/prevenção & controle , Prata/farmacologia , Humanos
4.
Braz J Biol ; 82: e232434, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-33681895

RESUMO

Many pathogenic strains have acquired multidrug-resistant patterns in recent a year, which poses a major public health concern. The growing need for effective antimicrobial agents as novel therapies against multidrug-resistant pathogens has drawn scientist attention toward nanotechnology. Silver nanoparticles are considered capable of killing multidrug-resistant isolates due to their oligo-dynamic effect on microorganisms. In this research study NPs were synthesized using the gram-positive bacteria Lactobacillus bulgaricus and its activity against selected pathogenic strains. Lactobacillus bulgaricus pure cultures were isolated from raw milk and grown in "De Man, Rogasa, and Sharp" broth for synthesis of nanoparticles. Lactobacillus bulgaricus culture was centrifuged and Cell- free supernatant of it was employed with aqueous silvery ions and evaluated their antibacterial activities against bacterial strains i.e. Staphylococcus aureus, Staphylococcus epidermidis and Salmonella typhi using agar well diffusion assay. Antibiotic profiling against selected pathogenic strains were also conducted using disc diffusion method. The synthesis and characterization of silver nanoparticles were monitored primarily by the conversion of the pale-yellow color of the mixture into a dark-brown color and via ultraviolet-visible absorption spectroscopy and Scanning electron microscopy respectively. The result showed that that AgNPs with size (30.65-100 nm) obtained from Lactobacillus bulgaricus were found to exhibit antibacterial activities against selected bacterial strains. Taken together, these findings suggest that Lactobacillus bulgaricus has great potential for the production of AgNPs with antibacterial activities and highly effective in comparison to tested antibiotics.


Assuntos
Anti-Infecciosos , Lactobacillus delbrueckii , Nanopartículas Metálicas , Antibacterianos/farmacologia , Testes de Sensibilidade Microbiana , Prata/farmacologia
5.
J Infect Public Health ; 14(3): 324-330, 2021 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-33618277

RESUMO

BACKGROUND: Streptococcus mutans are an oral pathogen that causes dental caries, endocarditis, and systemic dysfunctions, an alternative antibacterial solution from silver nanoparticles (AgNPs) are investigated. METHODS: AgNPs were synthesized using the ethnobotanical product gum Arabic. It influenced the nanoparticles with medicinal value through their role as capping, stabilizing, or surface-attached components. The biophysical characteristics of the synthesized AgNPs were studied using UV-vis spectrum, XRD, EDAX, SEM, and TEM tools. The AgNPs were spherical with the average size less than 10 nm. By using the well diffusion and microdilution techniques, the impact of synthesized AgNPs was tested against S. mutans isolates. RESULTS: The smaller the size, the greater the antibacterial and antiviral potential the particles exhibit. The biophysical characteristics of AgNPs the presence of phenols, alcohols, amides, sulfoxide, flavanoids, terpenoids and steroids. The AgNPs exhibited a good antibacterial action against the oral pathogen S. mutans. The synthesized NPs at a dose level of 200 µg/mL exhibited an inhibition zone with 18.30 ± 0.5 nm diameter. The synthesised nanoparticles inhibited the genes responsible for biofilm formation of S. mutans over host tooth and gums (gtfB, gtfc, gtfD) and virulent protective factors (comDE, brpA and smu 360) and survival promoter genes (gyrA and spaP, gbpB). CONCLUSION: The potent antibiotic action over S. mutans seen with the synthesized NPs, paves the way for the development of novel dental care products. Also, the small-sized NPs promote its applicability in COVID-19 pandemic containment.


Assuntos
Antibacterianos/farmacologia , Cárie Dentária/tratamento farmacológico , Endocardite/tratamento farmacológico , Nanopartículas Metálicas , Prata/farmacologia , Streptococcus mutans/efeitos dos fármacos , Biofilmes , Goma Arábica , Humanos
6.
Int J Nanomedicine ; 16: 1345-1360, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-33633450

RESUMO

Purpose: Despite the extensive development of antibacterial biomaterials, there are few reports on the effects of materials on the antibacterial ability of the immune system, and in particular of neutrophils. In this study, we observe differences between the in vivo and in vitro anti-infective efficacies of silver nanoparticles (AgNPs). The present study was designed to further explore the mechanism for this inconsistency using ex vivo models and in vitro experiments. Methods: AgNPs were synthesized using the polyol process and characterized by transmission electron microscopy and X-ray photoelectron spectroscopy. The antibacterial ability of AgNPs and neutrophils was tested by the spread-plate method. The infected air pouch model was prepared to detect the antimicrobial ability of AgNPs in vivo. Furthermore, blood-AgNPs-bacteria co-culture model and reactive oxygen species (ROS) measurement were used to evaluate the effect of AgNPs to neutrophil-mediated phagocytosis and ROS production. Results: The antibacterial experiments in vitro showed that AgNPs had superior antibacterial properties in cell compatible concentration. While, AgNPs had no significant antibacterial effect in vivo, and pathological section in AgNPs group indicated less neutrophil infiltration in inflammatory site than S. aureus group. Furthermore, AgNPs were found to reduce the phagocytosis of neutrophils and inhibit their ability to produce ROS and superoxide during ex vivo and in vitro experiments. Conclusion: This study selects AgNPs as the representative of inorganic nano-biomaterials and reveals the phenomenon and the mechanism underlying the significant AgNPs-induced inhibition of the antibacterial ability of neutrophils, and may have a certain enlightening effect on the development of biomaterials in the future. In the fabrication of antibacterial biomaterials, however, attention should be paid to both cell and immune system safety to make the antibacterial properties of the biomaterials and innate immune system complement each other and jointly promote the host's ability to resist the invasion of pathogenic microorganisms.


Assuntos
Antibacterianos/farmacologia , Sistema Imunitário/efeitos dos fármacos , Imunidade Inata/efeitos dos fármacos , Nanopartículas Metálicas/química , Neutrófilos/citologia , Fagocitose/efeitos dos fármacos , Espécies Reativas de Oxigênio/metabolismo , Prata/farmacologia , Animais , Movimento Celular/efeitos dos fármacos , Sobrevivência Celular/efeitos dos fármacos , Modelos Animais de Doenças , Feminino , Humanos , Mediadores da Inflamação/metabolismo , Nanopartículas Metálicas/ultraestrutura , Testes de Sensibilidade Microbiana , Neutrófilos/efeitos dos fármacos , RNA/metabolismo , Ratos Sprague-Dawley , Staphylococcus aureus/efeitos dos fármacos , Superóxidos/metabolismo
7.
Life Sci ; 272: 119262, 2021 May 01.
Artigo em Inglês | MEDLINE | ID: mdl-33639151

RESUMO

The perpetual lack of advanced strategies to prevent aggressive breast cancer with multiple categories represents challenging scientific society problems. Reduced graphene oxide- can treat disease, which was recently investigated due to its ability to induce apoptosis-based death. This research tested the chemotherapeutics in vitro efficacy of reduced graphene oxide embedded with gold and silver nanoparticles toward drug-sensitive breast cancer cells (MCF-7) and their cytotoxicity. Synthesis of the Au-Ag/rGO-5FU nanocomposites has been conducted using a wet chemical approach with chitosan aid as a pore directing and capping agent. The particle structure and morphology well characterized using different systems. HR-TEM shows a narrow-sized distribution of less than 100 nm, which is proper for cell membranes and medical use. The physical combination of the nanocomposite and 5-FU drug has been conducted mechanically using wet chemistry. The Au/Ag/rGO-5FU material's high activity enables it to produce reactive oxygen radicals, which display a potential against MCF-7 cell lines. All the results, including those obtained via cytometry, use the combination of Au/Ag/rGO-5FU to show a more substantial anticancer influence and more drug stability than pure 5-FU.


Assuntos
Neoplasias da Mama/tratamento farmacológico , Ouro/farmacologia , Grafite/farmacologia , Prata/farmacologia , Apoptose/efeitos dos fármacos , Linhagem Celular Tumoral , Sobrevivência Celular/efeitos dos fármacos , Fluoruracila/farmacologia , Ouro/química , Grafite/metabolismo , Humanos , Células MCF-7 , Nanopartículas Metálicas/química , Nanopartículas Metálicas/uso terapêutico , Nanocompostos/química , Espécies Reativas de Oxigênio/metabolismo , Prata/química
8.
Int J Nanomedicine ; 16: 851-865, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-33574666

RESUMO

Background: Ionizing radiation (IR) is commonly used in triple-negative breast cancer (TNBC) treatment regimens. However, off-target toxicity affecting normal tissue and grueling treatment regimens remain major limitations. Hyperthermia is one of the greatest IR sensitizers, but only if heat is administered simultaneously or immediately prior to ionizing radiation. Difficulty in co-localizing ionizing radiation (IR) in rapid succession with hyperthermia, and confining treatment to the tumor have hindered widespread clinical adoption of combined thermoradiation treatment. Metal nanoparticle-based approaches to IR sensitization and photothermal heat generation may aid in overcoming these issues and improve treatment specificity. Methods: We assessed the potential to selectively treat MDA-MB-231 TNBC cells without affecting non-malignant MCF-10A breast cells using a multimodal approach based upon combined photothermal therapy, IR sensitization, and specific cytotoxicity using triangular silver nanoparticles (TAgNPs) with peak absorbance in the near-infrared light (NIR) spectrum. Results: We found that TAgNP-mediated photothermal therapy and radiosensitization offer a high degree of specificity for treatment of TNBC without affecting non-malignant mammary epithelial cells. Discussion: If given at a high enough dose, IR, heat, or TAgNPs alone could be sufficient for tumor treatment. However, when the dose of one or all of these modalities increases, off-target effects also increase. The challenge lies in identifying the minimal doses of each individual treatment such that when combined they provide maximum selectivity for treatment of TNBC cells with minimum off-target effects on non-malignant breast cells. Our results provide proof of concept that this combination is highly selective for TNBC cells while sparing non-malignant mammary epithelial cells. This treatment would be particularly important for patients undergoing breast conservation therapy and for treatment of invasive tumor margins near the periphery where each individual treatment might be at a sub-therapeutic level.


Assuntos
Nanopartículas Metálicas/uso terapêutico , Radiação Ionizante , Prata/uso terapêutico , Neoplasias de Mama Triplo Negativas/tratamento farmacológico , Neoplasias de Mama Triplo Negativas/radioterapia , Animais , Apoptose/efeitos dos fármacos , Apoptose/efeitos da radiação , Carcinogênese/efeitos dos fármacos , Carcinogênese/patologia , Carcinogênese/efeitos da radiação , Linhagem Celular Tumoral , Sobrevivência Celular/efeitos dos fármacos , Sobrevivência Celular/efeitos da radiação , Terapia Combinada , Feminino , Humanos , Raios Infravermelhos , Nanopartículas Metálicas/ultraestrutura , Radiossensibilizantes/farmacologia , Radiossensibilizantes/uso terapêutico , Prata/farmacologia , Neoplasias de Mama Triplo Negativas/patologia
9.
Int J Mol Sci ; 22(2)2021 Jan 16.
Artigo em Inglês | MEDLINE | ID: mdl-33467032

RESUMO

Silver and its nanoparticles (AgNPs) have different faces, providing different applications. In recent years, the number of positive nanosilver applications has increased substantially. It has been proven that AgNPs inhibit the growth and survival of bacteria, including human and animal pathogens, as well as fungi, protozoa and arthropods. Silver nanoparticles are known from their antiviral and anti-cancer properties; however, they are also very popular in medical and pharmaceutical nanoengineering as carriers for precise delivery of therapeutic compounds, in the diagnostics of different diseases and in optics and chemistry, where they act as sensors, conductors and substrates for various syntheses. The activity of AgNPs has not been fully discovered; therefore, we need interdisciplinary research to fulfil this knowledge. New forms of products with silver will certainly find application in the future treatment of many complicated and difficult to treat diseases. There is still a lack of appropriate and precise legal condition regarding the circulation of nanomaterials and the rules governing their safety use. The relatively low toxicity, relative biocompatibility and selectivity of nanoparticle interaction combined with the unusual biological properties allow their use in animal production as well as in bioengineering and medicine. Despite a quite big knowledge on this topic, there is still a need to organize the data on AgNPs in relation to specific microorganisms such as bacteria, viruses or fungi. We decided to put this knowledge together and try to show positive and negative effects on prokaryotic and eukaryotic cells.


Assuntos
Anti-Infecciosos/química , Doenças Transmissíveis/tratamento farmacológico , Nanopartículas Metálicas/química , Prata/farmacologia , Animais , Anti-Infecciosos/farmacologia , Anti-Infecciosos/uso terapêutico , Biofilmes/efeitos dos fármacos , Humanos , Nanopartículas Metálicas/efeitos adversos , Nanopartículas Metálicas/uso terapêutico , Prata/química
10.
Carbohydr Polym ; 255: 117484, 2021 Mar 01.
Artigo em Inglês | MEDLINE | ID: mdl-33436244

RESUMO

Wound dressing composed of chitosan, based crosslinked gelatin/ polyvinyl pyrrolidone, embedded silver nanoparticles were fabricated using solution casting method. The membrane was characterized by FTIR, SEM and TGA. Glutaraldehyde (0.5 %) was used for the crosslinking of membrane components and associated with 7-folds boosted mechanical performance, 28 % more hydrolytic stability, 3-folds thickness reduction and morphological roughness. Silver nanoparticles were characterized by UV-vis, XRD and TEM for an average size of 9.9 nm. The membrane with higher concentration of silver nanoparticles showed maximum antibacterial activity against human pathogenic bacteria; and the measured inhibition zones ranged from 1.5 to 3 cm. The activity of the particles ranged from severe to complete reduction in Penicillin, Erythromycin and Macrolide family's resistance genes expression such as ß-Lactamase, mecA and erm. This developed membrane can serve as promising and cost-effective system against severe diabetic and burn wound infections.


Assuntos
Antibacterianos/farmacologia , Bandagens , Quitosana/química , Citrullus colocynthis/química , Gelatina/química , Povidona/química , Prata/farmacologia , Bacillus subtilis/efeitos dos fármacos , Bacillus subtilis/crescimento & desenvolvimento , Proteínas de Bactérias/genética , Proteínas de Bactérias/metabolismo , Farmacorresistência Bacteriana Múltipla/efeitos dos fármacos , Farmacorresistência Bacteriana Múltipla/genética , Eritromicina/farmacologia , Escherichia coli/efeitos dos fármacos , Escherichia coli/crescimento & desenvolvimento , Fibroblastos/citologia , Fibroblastos/efeitos dos fármacos , Regulação Bacteriana da Expressão Gênica/efeitos dos fármacos , Humanos , Macrolídeos/farmacologia , Nanopartículas Metálicas/química , Nanopartículas Metálicas/ultraestrutura , Metiltransferases/genética , Metiltransferases/metabolismo , Testes de Sensibilidade Microbiana , Proteínas de Ligação às Penicilinas/genética , Proteínas de Ligação às Penicilinas/metabolismo , Penicilinas/farmacologia , Cultura Primária de Células , Pseudomonas aeruginosa/efeitos dos fármacos , Pseudomonas aeruginosa/crescimento & desenvolvimento , Salmonella typhi/efeitos dos fármacos , Salmonella typhi/crescimento & desenvolvimento , Prata/química , Staphylococcus aureus/efeitos dos fármacos , Staphylococcus aureus/crescimento & desenvolvimento , beta-Lactamases/genética , beta-Lactamases/metabolismo
11.
Int J Nanomedicine ; 16: 481-492, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-33500618

RESUMO

Background: Dihydromyricetin (DMY), a natural flavonoid, has reportedly antibacterial, antioxidant, anticancer and other properties. In the present study, DMY was used as a reducing agent and stabilizer to synthesize silver nanoparticles (AgNPs), and the optimal conditions for its synthesis were studied. The DMY-AgNPs were investigated for their DPPH scavenging properties and their potential against human pathogenic and food-borne bacteria viz. Escherichia coli (E. coli), and Salmonella. In addition, DMY-AgNPs also showed excellent inhibitory effects on cancer Hela, HepG2 and MDA-MB-231 cell lines. Methods: The dihydromyricetin-mediated AgNPs (DMY-AgNPs) were characterized by ultraviolet-visible spectrophotometer (UV-Vis spectra), scanning electron microscopy (SEM), transmission electron microscopy (TEM), dynamic light scattering (DLS), Fourier-transform infrared spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS), and X-ray powder diffraction (XRD). Antioxidant activity of DMY-AgNPs was determined by 1.1-diphenyl-2-picrylhydrazyl (DPPH) scavenging. The antibacterial activity was determined by 96-well plate (AGAR) gradient dilution, while anticancer potential was determined by MTT assay. Results: The results showed that the dispersion of AgNPs had the maximum UV-visible absorption at about 410 nm. The synthesized nanoparticles were almost spherical. FTIR was used to identify functional groups that may lead to the transformation of metal ions into nanoparticles. The results showed that the prepared AgNPs were coated with biological molecules in the extraction solution. The biosynthesized DMY-AgNPs exhibited good antioxidant properties, at various concentrations (0.01-0.1mg/mL), the free radical scavenging rate was about 56-92%. Furthermore, DMY-AgNPs possessed good antibacterial properties against Escherichia coli (E. coli), and Salmonella at room temperature. The minimum inhibitory concentrations (MIC) were 10-6 g/L, and 10-4 g/L, respectively. The bioactivity of DMY-mediated AgNPs was studied using MTT assay against Hela, HepG2 and MDA-MB-231 cancer cell lines, and all showed good inhibitory effects. Conclusion: The present study provides a green approach for the synthesis of DMY-AgNPs which exhibited stronger antioxidant, antibacterial and anticancer properties compared to the dihydromyricetin. DMY-AgNPs can serve as an economical, efficient, and effective antimicrobial material for its applications in food and pharmaceutical fields.


Assuntos
Antibacterianos/farmacologia , Antineoplásicos/farmacologia , Antioxidantes/farmacologia , Flavonóis/farmacologia , Nanopartículas Metálicas/química , Prata/farmacologia , Bactérias/efeitos dos fármacos , Linhagem Celular Tumoral , Escherichia coli/efeitos dos fármacos , Humanos , Nanopartículas Metálicas/ultraestrutura , Testes de Sensibilidade Microbiana , Espectrofotometria Ultravioleta , Difração de Raios X
12.
Int J Nanomedicine ; 16: 15-29, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-33447027

RESUMO

Purpose: The present study investigates the phytosynthesis of silver nanoparticles (AgNPs) using Perilla frutescens leaf extract, which acts as a reducing agent for the conversion of silver ions (Ag+) into AgNPs. P. frutescens leaf synthesized AgNPs (PF@AgNPs) were evaluated for biomedical properties including antibacterial, antioxidant and anticancer activities. Materials and Methods: PF@AgNPs were synthesized using P. frutescens leaf extract and silver nitrate solution. The morphology and physical properties of PF@AgNPs were studied by spectroscopic techniques including, UV-Vis, FTIR, TEM, XRD, DLS, and TGA. Antibacterial activity of PF@AgNPs was evaluated by disk diffusion assay. Antioxidant activity of PF@AgNPs was checked by 2.2-diphenyl-1-picrylhydrazyl (DPPH), and 2.2'-azino-bis (3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) free radical scavenging assays. Anticancer activity of PF@AgNPs was checked by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide assay. Cytotoxic effects of PF@AgNPs on most susceptible cancer cell lines were observed by phase contrast microscopy. Results: PF@AgNPs showed surface plasmon resonance peak at 461 nm. XRD pattern showed that the PF@AgNPs were face-centered cubic crystals with a mean size of 25.71 nm. TEM analysis revealed the different shapes (spherical, rhombic, triangle, and rod) of PF@AgNPs. Zeta potential value (-25.83 mV) indicated that PF@AgNPs were long-term stable and not agglomerated. A low polydispersity index value (0.389) indicated the monodispersity of PF@AgNPs. TGA revealed the high thermal stability of PF@AgNPs. PF@AgNPs exhibited maximum inhibition against Escherichia coli, followed by Bacillus subtilis and Staphylococcus aureus. PF@AgNPs showed maximum inhibition of 68.02 and 62.93% against DPPH and ABTS-free radicals, respectively. PF@AgNPs showed significant anticancer activity against human colon cancer (COLO205) and prostate adenocarcinoma (LNCaP). PF@AgNPs exhibited apoptotic effects on LNCaP cells including cell shrinkage, membrane blebbing, chromatin condensation, fragmentation of nuclei, and formation of apoptotic bodies. Conclusion: The present study reports the successful synthesis of PF@AgNPs using P. frutescens leaf extract. The synthesized PF@AgNPs are FCC crystals, monodispersed, long-term stable, and non-agglomerated. The observed antibacterial, antioxidant, and anticancer activities demonstrate the potential biomedical applications of PF@AgNPs.


Assuntos
Antibacterianos/farmacologia , Antineoplásicos/farmacologia , Antioxidantes/farmacologia , Nanopartículas Metálicas/química , Perilla frutescens/química , Extratos Vegetais/química , Folhas de Planta/química , Prata/farmacologia , Bacillus subtilis/efeitos dos fármacos , Compostos de Bifenilo/química , Linhagem Celular Tumoral , Cor , Difusão Dinâmica da Luz , Escherichia coli/efeitos dos fármacos , Depuradores de Radicais Livres/farmacologia , Humanos , Nanopartículas Metálicas/ultraestrutura , Testes de Sensibilidade Microbiana , Picratos/química , Espectrofotometria Ultravioleta , Espectroscopia de Infravermelho com Transformada de Fourier , Staphylococcus aureus/efeitos dos fármacos , Eletricidade Estática , Termogravimetria , Difração de Raios X
13.
Carbohydr Polym ; 252: 117156, 2021 Jan 15.
Artigo em Inglês | MEDLINE | ID: mdl-33183607

RESUMO

A new natural formulation composed of CMC and various contents of CNC immobilized AgNPs (CNC@AgNPs) was developed for paper coating. The mechanical strength, water vapor and air barrier properties, and antibacterial activities of CMC/CNC@AgNPs coated paper improved with the increasing content of CNC@AgNPs. CMC/CNC@AgNPs7 % coated paper exhibited 1.26 times increase in tensile strength, 45.4 % decrease in WVP, 93.3 % reduction in air permeability as well as the best antibacterial activities against E.coli and S.aureus compared with uncoated paper. Moreover, the cumulative release rate of AgNPs from coated paper significantly reduced due to the immobilization effect of CNC on AgNPs. Furthermore, CMC/CNC@AgNPs coated paper was used to package strawberries under ambient conditions. The results showed that coated paper could maintain better strawberries quality compared with unpackaged strawberries and extend the shelf-life of strawberries to 7 days. Therefore, the prepared CMC/CNC@AgNPs coated paper will have a great application prospect in the food packaging.


Assuntos
Antibacterianos/farmacologia , Carboximetilcelulose Sódica/química , Embalagem de Alimentos , Nanopartículas Metálicas/química , Nanocompostos/química , Prata/farmacologia , Escherichia coli/efeitos dos fármacos , Permeabilidade , Staphylococcus aureus/efeitos dos fármacos , Vapor , Resistência à Tração
14.
Carbohydr Polym ; 251: 117017, 2021 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-33142578

RESUMO

The synthesis and specific surface functionalization of antimicrobial silver nanoparticles (AgNPs) and their incorporation into an alginate hydrogel is described. Divalent cation-mediated ionic crosslinking was used to disperse the AgNPs throughout the gel, made possible by -COO- cross-linking sites provided by the surface-enhanced nanoparticles, inspired by the classic egg-box model crosslinking of calcium alginate. An AgNP concentration, 10-20 µg g-1 increased hygrogel elasticity, viscosity, and shear resistance by 45, 30, and 31% respectively. Cryo-TEM revealed evenly distributed AgNP assemblies of discrete AgNPs throughout the gel matrices. FTIR-ATR indicated AgNPs were involved in alginate carboxylate-Ca2+-COO-AgNP crossbridging, which was not achieved through mixing of AgNPs into preformed gels. Live/dead fluorometric assays determined a minimal bactericidal concentration of 25 µg g-1 Ag for 6 microorganisms. Anti-biofilm assays showed species-dependent cell death of 44 -61%, with limited silver ion release of 0.41% and 1.1% after 7 days for Gram positive and negative bacteria, respectively.


Assuntos
Alginatos/química , Antibacterianos/farmacologia , Bactérias/efeitos dos fármacos , Biofilmes/efeitos dos fármacos , Hidrogéis/química , Prata/farmacologia , Nanopartículas Metálicas/química , Nanogéis/química
15.
Carbohydr Polym ; 251: 117024, 2021 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-33142584

RESUMO

Nanocrystalline jute cellulose (NCJC) particles were prepared from bleached jute pulp by a modified acid hydrolysis. The surface of NCJC particles were first modified with iron oxide nanoparticles and then with Ag nanoparticles to prepare antibacterial NCJC/Fe3O4/Ag nanocomposite particles. The successive structural modification of NCJC particles with Fe3O4 and Ag nanoparticles was confirmed. NCJC/Fe3O4/Ag nanocomposite particles responded well in external magnetic field. The SEM and TEM images of NCJC particles were in the nanometer range. NCJC/Fe3O4/Ag nanocomposite particles (0.005 mg mL-1) completely degraded 20 mL of 0.1 mM congo red aqueous solution within 13 min aided by NaBH4 reducing agent. NCJC/Fe3O4/Ag nanocomposite particles were moderately active against both Gram positive and Gram negative bacteria. A maximum inhibition zone of 21 mm was observed against Gram negative Shigella boydii bacteria with 60 mg/disc of nanocomposite particles. The antioxidant property of nanocomposite particles was also positive.


Assuntos
Antibacterianos , Antioxidantes , Celulose/química , Nanopartículas de Magnetita/química , Nanocompostos/química , Prata/farmacologia , Antibacterianos/química , Antibacterianos/farmacologia , Antioxidantes/química , Antioxidantes/farmacologia , Corchorus/química , Bactérias Gram-Negativas/efeitos dos fármacos , Staphylococcus aureus/efeitos dos fármacos
16.
Carbohydr Polym ; 254: 117464, 2021 Feb 15.
Artigo em Inglês | MEDLINE | ID: mdl-33357923

RESUMO

The fabrication of polymeric composite hydrogel with hierarchical structure in a simple, controllable, and straightforward process poses great importance for manufacturing nanomaterials and subsequent applications. Herein, we report a one-step and template-free counterion exchange method to construct free-standing carboxylated cellulose nanofiber composite hydrogels. Metal ions were electrochemically and locally released from the electrode and chelated with carboxylated cellulose nanofibers, leading to the in-situ formation of composite hydrogels. The properties of composite hydrogels can be easily programmed by the type of electrode, current density, and electrodeposited suspension. Significantly, the composited hydrogels exhibited interconnected nanoporous structure, enhanced thermal degradation, improved mechanical strength and antibacterial activity. The results suggest great potential of anodic electrodeposition to fabricate nanofiber/metal composite hydrogels.


Assuntos
Antibacterianos/química , Celulose/análogos & derivados , Técnicas Eletroquímicas , Nanofibras/química , Feófitas/química , Antibacterianos/farmacologia , Cátions Bivalentes , Cátions Monovalentes , Celulose/ultraestrutura , Cobre/química , Cobre/farmacologia , Eletrodos , Escherichia coli/efeitos dos fármacos , Escherichia coli/crescimento & desenvolvimento , Hidrogéis , Ferro/química , Ferro/farmacologia , Testes de Sensibilidade Microbiana , Nanofibras/ultraestrutura , Prata/química , Prata/farmacologia , Staphylococcus aureus/efeitos dos fármacos , Staphylococcus aureus/crescimento & desenvolvimento , Resistência à Tração , Resíduos
17.
Int J Nanomedicine ; 15: 10425-10434, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-33376330

RESUMO

Purpose: The public fear associated with the novel coronavirus (SARS-CoV-2) pandemic has triggered recently a significant proliferation of supplements touted as potential cures against bacteria and viruses. Colloidal silver has particularly benefited from this rush given its empirically and scientifically documented anti-bacterial and anti-viral actions. The lack of standards in the unregulated supplements industry remains a major roadblock in evaluating the quality and consistency of marketed products or assessing the accuracy of the information provided by manufacturers. This study is the first scientifically rigorous attempt to evaluate commercial silver colloidal products offered for sale on the internet. Methods: Fourteen of the most popular colloidal silver products purchased from Amazon (www.amazon.com) were evaluated using state-of-the-art analytical techniques widely accepted as gold standards for investigating the properties (size, shape) and the dispersion of silver nanoparticles. Results: Commercial samples were analysed using UV-Vis, FE-SEM and AAS techniques. In general, the Ag concentration was very close to those claimed by the manufacturer. The colorless product shows no absorbance in the UV-Vis analysis. The FESEM and STEM images confirmed the conclusions of the UV-Vis analysis. Conclusion: The results of this evaluation show clearly that 70% of the commercial products evaluated contain only ionic silver. Despite the evidence showing that silver nanoparticles are not present, eight of these products are promoted by the manufacturers as 'colloidal silver'. Considering the extensive scientific research showing major differences between silver ionic and silver nanoparticles in terms of mechanisms of action, efficacy and safety, it is clear that this misrepresentation impacts the consumers and must be addressed. This study serves as blueprint for a scientific protocol to be followed by manufacturers for characterizing their silver supplements.


Assuntos
Antibacterianos/química , Prata/química , Antibacterianos/efeitos adversos , Antibacterianos/farmacologia , Humanos , Nanopartículas Metálicas/química , Segurança , Prata/efeitos adversos , Prata/farmacologia
18.
PLoS One ; 15(12): e0244511, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-33373403

RESUMO

In this work, the effect of the inoculation of silver-incorporated titanium dioxide nanoparticles (Ag-TiO2 NPs) in spinach seeds was evaluated on certain growth, physiology and phytotoxicity parameters of the plants. This is an important crop for human consumption with high nutritional value due to their low calorie and fat content, providing various vitamins and minerals, especially iron. These NPs were obtained by means of the sol-gel method and heat treatment; the resulting powder material was characterized using X-ray diffraction and scanning electron microscopy and the influence of these NPs on plants was measured by estimating the germination rate, monitoring morphological parameters and evaluating phytotoxicity. The photosynthetic activity of the spinach plants was estimated through the quantification of the Ratio of Oxygen Evolution (ROE) by the photoacoustic technique. Samples of TiO2 powder with particle size between 9 and 43 nm were used to quantify the germination rate, which served to determine a narrower size range between 7 and 26 nm in the experiments with Ag-TiO2 NPs; the presence of Ag in TiO2 powder samples was confirmed by energy-dispersive X-ray spectroscopy. The analysis of variance showed that the dependent variable (plant growth) could be affected by the evaluated factors (concentration and size) with significant differences. The statistical trend indicated that the application of the Ag-TiO2 NPs suspension of lowest concentration and smallest particle size could be a promoting agent of the growth and development of these plants. The inoculation with NPs of 8.3 nm size and lowest concentration was related to the highest average ROE value, 24.6 ± 0.2%, while the control group was 20.2 ± 0.2%. The positive effect of the Ag-TiO2 NPs treatment could be associated to the generation of reactive oxygen species, antimicrobial activity, increased biochemical attributes, enzymatic activity or improvements in water absorption.


Assuntos
Fertilizantes , Nanopartículas Metálicas , Prata/farmacologia , Spinacia oleracea/efeitos dos fármacos , Titânio/farmacologia , Germinação/efeitos dos fármacos , Espécies Reativas de Oxigênio/metabolismo , Plântula/efeitos dos fármacos , Plântula/crescimento & desenvolvimento , Plântula/metabolismo , Spinacia oleracea/fisiologia , Suspensões , Testes de Toxicidade
19.
An Acad Bras Cienc ; 92(4): e20191584, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-33206788

RESUMO

In this work, the natural latex extracted from Harconia speciosa was incorporated with silver nanoparticles (AgNP) to compose a functional biomaterial associating the intrinsic angiogenic activity of the latex and the antimicrobial activity of AgNP. Tissue reaction after subcutaneous implantation in dorsum of rats of membranes without AgNP and with 0.05%, 0.4% AgNP was compared at 3, 7 and 25 days. No statistically significant difference in the tissue response of the different biomaterials was observed, indicating that AgNP did not interfere with the inflammatory reaction (p > 0.05) or with the angiogenic activity of latex. Biomembranes were also tested against bacterial biofilm formation by Staphylococcus aureus and the antimicrobial activity of the new biomaterial can be found with bacteria crenation (0.05% AgNP) and no biofilm deposition (0.4% AgNP). Therefore, this biomaterial has interesting properties for the tissue repair process and may be feasible for future applications as dressing.


Assuntos
Látex , Nanopartículas Metálicas , Animais , Antibacterianos/farmacologia , Materiais Biocompatíveis/farmacologia , Biofilmes , Ratos , Prata/farmacologia
20.
Braz Dent J ; 31(5): 485-492, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-33146331

RESUMO

Green chemistry has been applied in different areas due to the growing demands for renewable processes and one of them is nanotechnology. The aim of this study was to characterize a formulation containing silver nanoparticles (AgNPs) produced by a green synthesis and to evaluate its antimicrobial activity. The formulation will be used as an intracanal dressing exploiting the AgNPs' antimicrobial properties, which are crucial to prevent infections and bacterial reinfections that can compromise endodontic treatments. In the green synthesis, silver nitrate was employed as the precursor salt, maltose as a reducing agent, and gelatin as a stabilizing agent. The formulation was prepared mixing 50 % of a liquid containing the AgNPs and 50 % of hydroxyethylcellulose gel at 1.5 % with proper evaluation of the process inherent parameters. Techniques such as molecular absorption spectrometry and dynamic light scattering were used in characterization step. The antimicrobial activity of the AgNPs against Escherichia coli ATCC 25922, Enterococcus faecalis NCTC 775, Pseudomonas aeruginosa ATCC 27853, Staphylococcus aureus ATCC 25923 and Streptococcus mutans ATCC 25175 was verified according to National Comittee for Clinical Laboratory Standards (NCCLS) by determining minimal inhibitory concentration (MIC) and minimal bactericidal concentration (MBC). The obtained results indicated the formulation containing AgNPs produced by a green synthesis was properly characterized by the selected techniques. Furthermore, the formulation assessment proved that it is suitable for the proposal as well as it has potential to be used as an intracanal dressing since presented antimicrobial activity against all bacterial strains evaluated.


Assuntos
Anti-Infecciosos , Nanopartículas Metálicas , Antibacterianos/farmacologia , Anti-Infecciosos/farmacologia , Bandagens , Testes de Sensibilidade Microbiana , Prata/farmacologia
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