RESUMO
AIM: The objective of this study was to develop nanostructured gels as biocompatible intracanal disinfectants by one-step microwave radiation-assisted synthesis. METHODS: Polyvinyl alcohol (PVA) and polyvinyl pyrrolidone (PVP) were used as a support network, and polyethylene glycol (PEG) was used as a reducing agent. The gels were characterized by measuring the swelling ratio (SR) and rheological properties and by scanning electron microscopy (SEM), transmission electron microscopy (TEM) and atomic force microscopy (AFM). The antibacterial effects of each gel were evaluated against the endodontic clinical strain Enterococcus faecalis. Then, the viability of the 21-day mature multispecies bacterial biofilm was assessed using confocal microscopy in an ex vivo model, where the biofilm was exposed to the mix of nanogels. The cell proliferation, viability, and morphology of human periodontal ligament (HPDL) cells were quantified using a real-time IncuCyte® S3 Live-Cell System. Viability was measured by confocal microscopy using an ex vivo model exposing a 21-day mature multispecies bacterial biofilm to the mix of nanogels. RESULTS: The antibacterial activity of the gels coincided with the superficial characterization and the solubility of the gel in the growth medium. Gels with higher viscosity (327.85-980.58 Pa s), higher dissolution (42-70%SR), and lower porosity (no porosity and 611.63 nm) showed excellent antibacterial activity against E. faecalis. Despite their physicochemical characteristics, CuNPs gels showed greater effectiveness against E. faecalis.These nanostructured gels with high PVA concentrations promote HPDL cells proliferation while still exerting antibacterial properties. Mix of nanogels showed an increase non-viable cells biomass from at of application. CONCLUSIONS: The use of biocompatible polymers influences the physicochemical, bactericidal, and cytotoxic response, making these materials potential disinfectant agents against resistant bacteria with good biocompatibility and improved HPDL cells proliferation.
Assuntos
Desinfetantes , Nanoestruturas , Humanos , Desinfetantes/farmacologia , Nanogéis , Antibacterianos/farmacologia , Géis/farmacologia , Enterococcus faecalis , BiofilmesRESUMO
Bacterial cystitis is a common clinical problem among cats and dogs and is one of the main reasons for the administration of antimicrobials. This can cause serious damage to public and animal health, as this practice facilitates the selection of bacteria that are multidrug-resistant to antibiotics. In this context, it is urgent to understand and validate therapeutic modalities that complement antimicrobial treatment in cystitis cases. Ozone therapy has been proposed by scientists owing to the various mechanisms of action in a range of pathologies, both in human and animal medicine. This paper describes the bactericidal action of two different protocols of bladder irrigation with ozonized saline solution (59 µg/mL) in a paraplegic canine with recurrent bacterial cystitis caused by Proteus spp. In the first protocol, the bladder instillations were applied once a day for three consecutive days while in the second, successive lavages were performed throughout the day until a significant reduction in the presence of bacteria in the urine sediment. In this study, we were able to demonstrate that repeated bladder instillation within 24 hours was the most effective treatment for Proteus compared to a single instillation on successive days.
Assuntos
Cistite , Solução Salina , Animais , Cães , Humanos , Gatos , Solução Salina/uso terapêutico , Cistite/tratamento farmacológico , Cistite/microbiologia , Cistite/patologia , Resultado do Tratamento , ProteusRESUMO
Carvacrol has been recognized as an efficient growth inhibitor of food pathogens. However, carvacrol oil is poorly water-soluble and can be oxidized, decomposed or evaporated when exposed to the air, light, or heat. To overcome these limitations, a carvacrol nanoemulsion was developed and its antimicrobial activity against food pathogens evaluated in this study. The nanoemulsion containing 3% carvacrol oil, 9% surfactants (HLB 11) and 88% water, presented good stability over a period of 90 days. In general, the carvacrol nanoemulsion (MIC: 256 µg ml-1 for E. coli and Salmonella spp., 128 µg ml-1 for Staphylococcus aureus and Pseudomonas aeruginosa) exhibited improved antimicrobial activity compared to the free oil. The carvacrol nanoemulsion additionally displayed bactericidal activity against Escherichia coli, P. aeruginosa and Salmonella spp. Therefore, the results of this study indicated that carvacrol oil nanoemulsions can potentially be incorporated into food formulations, wherein their efficacy for the prevention and control of microbial growth could be evaluated.
Assuntos
Antibacterianos/farmacologia , Cimenos/farmacologia , Escherichia coli/efeitos dos fármacos , Pseudomonas aeruginosa/efeitos dos fármacos , Salmonella/efeitos dos fármacos , Staphylococcus aureus/efeitos dos fármacos , Infecções por Escherichia coli/prevenção & controle , Microbiologia de Alimentos , Doenças Transmitidas por Alimentos/prevenção & controle , Testes de Sensibilidade Microbiana , Monoterpenos/farmacologia , Óleos Voláteis/farmacologia , Intoxicação Alimentar por Salmonella/prevenção & controle , Infecções Estafilocócicas/prevenção & controle , Tensoativos/farmacologiaRESUMO
Bacteriocins are ribosomally synthesized peptides with antibacterial activity against food-borne pathogenic bacteria that cause spoilage, possessing important potential for use as a natural preservative in the food industry. The novel bacteriocin BM1300 produced by Lactobacillus crustorum MN047 was identified after purification in this study. It displayed broad-spectrum antibacterial activity against some selected Gram-positive and Gram-negative bacteria. The minimum inhibitory concentration (MIC) values of BM1300 against Staphylococcus aureus ATCC 25923 and Escherichia coli ATCC 25922 were 13.4 µg/mL and 6.7 µg/mL, respectively. Moreover, BM1300 showed excellent thermal (between 60 and 120 °C), pH (2-11), and chemical (Tween-40, Tween-80, Triton X-100, and EDTA) stabilities. Time-kill curves revealed that BM1300 exhibited bactericidal activity against S. aureus and E. coli. The scanning and transmission electron microscopy indicated that BM1300 acted by disrupting the cell membrane integrity and increasing cell membrane permeabilization of indicator bacteria. The disruption of cell membrane integrity caused by BM1300 was further demonstrated by the uptake of propidium iodide (PI) and the release of intracellular lactate dehydrogenase (LDH) and nucleic acid and proteins. Moreover, BM1300 affected cell cycle distribution to exert antibacterial activity collaboratively. Meanwhile, BM1300 inhibited the growth of S. aureus and E. coli of beef meat and improved the microbiological quality of beef meat. These findings place BM1300 as a potential biopreservative in the food industry.
Assuntos
Antibacterianos/farmacologia , Bacteriocinas/farmacologia , Lactobacillus/química , Animais , Antibacterianos/classificação , Eritrócitos/efeitos dos fármacos , Escherichia coli/genética , Escherichia coli/metabolismo , Bactérias Gram-Negativas/efeitos dos fármacos , Bactérias Gram-Positivas/classificação , Bactérias Gram-Positivas/efeitos dos fármacos , Hemólise , Camundongos , Testes de Sensibilidade MicrobianaRESUMO
Herein, we electrospun ultrathin core-shell fibers based on polycaprolactone (PCL), polyethylene glycol (PEG), gelatin and osteogenic growth peptide (OGP), and evaluated their potential to upregulate human osteoblast cells (hFOB) and to reduce Gram-positive and Gram-negative bacteria. We also evaluated the fiber morphology, chemical structure and peptide delivery efficacy. The employment of core-shell fibers compared to fibers without a core-shell showed improved mechanical strength, comparable to the strength of pure PCL, as well as improved hydrophilicity and wettability. The careful selection of polymer combination and core-shell strategy promoted a controlled and sustained release of OGP. Moreover, increased calcium deposition (CD) (1.3-fold) and alkaline phosphate (ALP) activity was observed when hFOBs were cultivated onto core-shell fibers loaded with OGP after 21â¯days of culture. Our developed scaffolds were also able to reduce the amount of Pseudomonas aeruginosa (ATCC 25668) bacteria by a factor of two compared to raw PCL without the use of any antibiotics. All of these results demonstrate a promising potential of the developed core-shell electrospun scaffolds based on PCL:PEG:Gelatin:OGP for numerous bone tissue applications.
Assuntos
Diferenciação Celular/efeitos dos fármacos , Histonas , Peptídeos e Proteínas de Sinalização Intercelular , Staphylococcus aureus Resistente à Meticilina/crescimento & desenvolvimento , Osteoblastos/metabolismo , Pseudomonas aeruginosa/crescimento & desenvolvimento , Engenharia Tecidual , Alicerces Teciduais/química , Linhagem Celular , Histonas/química , Histonas/farmacologia , Humanos , Peptídeos e Proteínas de Sinalização Intercelular/química , Peptídeos e Proteínas de Sinalização Intercelular/farmacologiaRESUMO
The potential phytochemical losses occurring throughout the sequential steps of in-vitro gastrointestinal digestion and colonic fermentation of a rosemary aqueous extract were investigated. Crude (CE), digested (DE) and fermented (FE) extracts were characterized in terms of their phenolic profile and biological activities. Rosmarinic acid was the phytochemical that underwent the most significate transformation during digestion and fermentation, which amounted to 60% compared to the 26% degradation of the total phenolics. Overall, the simulated digestion step decreased the antioxidant activity estimated by DPPH, ABTS, FRAP, ORAC and TBARS assays. Both CE and DE did not present antiproliferative potential, however, FE exhibited a pronounced cytotoxic activity (GI50â¯=â¯116⯵g/mL) against HeLa cells. CE and DE showed to be moderate inhibitors of methicillin-resistant Staphylococcus aureus (MRSA), methicillin-susceptible S. aureus (MSSA), S. aureus, Listeria monocytogenes, whilst the FE acted as a moderate inhibitor of MRSA and MSSA.
Assuntos
Cinamatos/química , Depsídeos/química , Digestão , Fermentação , Rosmarinus/química , Antioxidantes , Cinamatos/farmacologia , Depsídeos/farmacologia , Células HeLa , Humanos , Técnicas In Vitro , Staphylococcus aureus Resistente à Meticilina/efeitos dos fármacos , Extratos Vegetais , Staphylococcus aureus , Ácido RosmarínicoRESUMO
The purpose of this study was to evaluate the most appropriate conditions to generate silver nanoparticles (AgNPs) loaded with a potent antimycotic drug like amphotericin B (AmB), characterize the physicochemical properties, and to evaluate the cytotoxic effect and biological activity of these new nanostructures as a potential nanocarrier for hydrophobic drugs. It was determined that the optimal molar ratio between Ag and AmB is 1/1 given the uniformity of size around 170 nm of the nanoparticles generated as well as their strongly negative ζ potential of -35 mV, a condition that favors repulsions between AgNPs and inhibiting their aggregation. In this condition, only 0.8 mg.mL-1 of Ag is needed to solubilize 5 mg.mL-1 of AmB, a concentration currently used in commercial formulations. It is important to emphasize that the loading capacity (w/w) of this nanostructure is much higher than that of micellar and liposomal formulations. These AgNP-AmB nanoparticles retain both the bactericidal effect of silver and the cytotoxic and antifungal effect of AmB. However, it was shown that these nanoparticles are spontaneously associated with plasma lipoproteins (LDL and HDL), inhibiting their cytotoxic effects on red blood cells and on at least two cell lines, Vero and H1299 and slightly reducing its bactericidal effect on P. aeruginosa. In contrast, the antifungal effect of the formulation is maintained and is even higher than that when the nanoparticle is not associated with lipoproteins, indicating that this association is of the reversible type. The characterization of these nanoparticles is discussed as a potential new model formulation able to improve the antifungal therapeutic efficiency of AmB.
Assuntos
Anfotericina B/farmacologia , Antibacterianos/farmacologia , Antifúngicos/farmacologia , Candida albicans/efeitos dos fármacos , Nanopartículas Metálicas/química , Pseudomonas aeruginosa/efeitos dos fármacos , Prata/farmacologia , Anfotericina B/química , Animais , Antibacterianos/química , Antifúngicos/química , Sobrevivência Celular/efeitos dos fármacos , Células Cultivadas , Chlorocebus aethiops , Eritrócitos/efeitos dos fármacos , Humanos , Testes de Sensibilidade Microbiana , Conformação Molecular , Tamanho da Partícula , Prata/química , Solubilidade , Propriedades de Superfície , Células VeroRESUMO
Graphene oxide nanoribbons (O-GNR) surges as an interesting nanomaterial for biomedical applications due to feasibility to incorporate functional groups and possible bactericidal properties. Herein, high concentrations of O-GNR were biologically evaluated using human osteoblast cells and gram positive and negative bacteria. Briefly, our goal were to evaluate: (1) synthetic pathway, (2) characterization and (3) effects of O-GNR composition and structural factors as a new approach for biomedical applications. For this, O-GNR were produced combining chemical vapor deposition and oxygen plasma treatment of multiwalled carbon nanotubes. Then, we analyzed the bioactivity, cell viability, osteogenic differentiation, matrix mineralization, mRNA levels of the five genes related direct to bone repair and bactericidal effect of high concentrations of O-GNR (10µgmL-1, 100µgmL-1, 200µgmL-1 and 300µgmL-1). Impressively, O-GNR showed no cytotoxic effects up to a concentration of 100µgmL-1 and no gene expression alteration when used in its dose. We also observed that S. aureus and E. coli bacteria are susceptible to damage when incubated with 100µgmL-1 of O-GNR, showing approximately 50% of bacterial death. We consider that O-GNR displays attractive properties when used at a suitable dose, displaying bactericidal effect and apparently lacking to cause damages in the bone repair process.
Assuntos
Nanotubos de Carbono , Regeneração Óssea , Escherichia coli , Grafite , Humanos , Nanoestruturas , Osteogênese , Óxidos , Staphylococcus aureusRESUMO
Researchers have been looking for modifying surfaces of polymeric biomaterials approved by FDA to obtain nanofeatures and bactericidal properties. If modified, it would be very interesting because the antibiotic administration could be reduced and, therefore, the bacterial resistance. Here, we report the electrospinning of poly (lactic acid) (PLA) with high loadings of titanium dioxide nanoparticles (TiO2, 1-5wt%) and their bactericidal properties. TiO2 nanoparticles have been recognized for a long time for their antibacterial, low cost and self-cleaning properties. However, their ability to reduce bacteria functions when used in polymers has not been well studied to date. In this context, we aimed here to generate nanostructured PLA electrospun fiber-TiO2 nanoparticle composites for further evaluation of their bactericidal activity and cell viability. TEM and SEM micrographs revealed the successful electrospinning of PLA/TiO2 and the generation of polymer-TiO2 nanostructures. When increasing the TiO2 concentration, we observed a proportional increase in the nanoparticle density along the fiber and surface. The nanostructured PLA/TiO2 nanofibers showed no mammalian cell toxicity and, most importantly, possessed bactericidal activity with higher TiO2 loads. Such results suggest that the present PLA electrospun fiber-TiO2 nanoparticle composites should be further studied for a wide range of biomedical applications.
Assuntos
Antibacterianos , Nanofibras/química , Nanopartículas/química , Poliésteres , Staphylococcus aureus/crescimento & desenvolvimento , Titânio , Animais , Antibacterianos/química , Antibacterianos/farmacologia , Linhagem Celular , Humanos , Poliésteres/química , Poliésteres/farmacologia , Ratos , Titânio/química , Titânio/farmacologiaRESUMO
Nanohydroxyapatite (nHAp) is an emergent bioceramic that shows similar chemical and crystallographic properties as the mineral phase present in bone. However, nHAp presents low fracture toughness and tensile strength, limiting its application in bone tissue engineering. Conversely, multi-walled carbon nanotubes (MWCNTs) have been widely used for composite applications due to their excellent mechanical and physicochemical properties, although their hydrophobicity usually impairs some applications. To improve MWCNT wettability, oxygen plasma etching has been applied to promote MWCNT exfoliation and oxidation and to produce graphene oxide (GO) at the end of the tips. Here, we prepared a series of nHAp/MWCNT-GO nanocomposites aimed at producing materials that combine similar bone characteristics (nHAp) with high mechanical strength (MWCNT-GO). After MWCNT production and functionalization to produce MWCNT-GO, ultrasonic irradiation was employed to precipitate nHAp onto the MWCNT-GO scaffolds (at 1-3 wt%). We employed various techniques to characterize the nanocomposites, including transmission electron microscopy (TEM), Raman spectroscopy, thermogravimetry, and gas adsorption (the Brunauer-Emmett-Teller method). We used simulated body fluid to evaluate their bioactivity and human osteoblasts (bone-forming cells) to evaluate cytocompatibility. We also investigated their bactericidal effect against Staphylococcus aureus and Escherichia coli. TEM analysis revealed homogeneous distributions of nHAp crystal grains along the MWCNT-GO surfaces. All nanocomposites were proved to be bioactive, since carbonated nHAp was found after 21 days in simulated body fluid. All nanocomposites showed potential for biomedical applications with no cytotoxicity toward osteoblasts and impressively demonstrated a bactericidal effect without the use of antibiotics. All of the aforementioned properties make these materials very attractive for bone tissue engineering applications, either as a matrix or as a reinforcement material for numerous polymeric nanocomposites.
Assuntos
Durapatita/farmacologia , Grafite/química , Nanotubos de Carbono/química , Alicerces Teciduais/química , Linhagem Celular , Cristalização , Escherichia coli/efeitos dos fármacos , Humanos , Nanocompostos/química , Nanocompostos/ultraestrutura , Nanotubos de Carbono/ultraestrutura , Osteoblastos/efeitos dos fármacos , Porosidade , Espectroscopia de Infravermelho com Transformada de Fourier , Análise Espectral Raman , Staphylococcus aureus/efeitos dos fármacos , Termogravimetria , Difração de Raios XRESUMO
The aim of this work was to investigate the disinfectant effect of electrolysis on chlorine-free water, artificially contaminated with Escherichia coli (CCT-1457) and to evaluate the bactericidal activity of electrolysis and kinetic behavior of a single-cell reactor, with a DSA (Dimensionally Stable Anode) electrode to develop a scaled-up system. A high-density E. coli suspension (10(6) CFU mL-1) was electrolyzed in this reactor at 25, 50 and 75 mA cm-2 for up to 60 min, at flow rates of 200 and 500 L h-1. Bacterial survival fell by 98.9 percent without addition of chlorinated compounds and a power consumption rate not more than 5.60 kWh m-3 at flow rate of 200 L h-1 and 75 mA cm-2. The process produced a germicidal effect that reached this inactivation rate within a relatively short contact time. Also, a solution of electrolyzed 0.08 M Na2SO4 added to the inoculum showed residual bactericidal effect. The efficiency of disinfection was regulated by both the contact time and current density applied, and a kinetic function for the survival rate was developed for the purpose of scaling up.
Água contaminada é uma das maiores origens de doenças em seres humanos. Em todo o mundo, a cloração é o método mais utilizado para promover desinfecção em águas de abastecimento devido ao seu efeito residual, quando adequadamente calculado. Contudo, se a água apresentar matéria orgânica, pode haver a geração de organoclorados, os quais são genotóxicos e carcinogênicos. Sob esta óptica, investigamos o efeito bactericida da aplicação da eletrólise em água sem cloro contaminada com Escherichia coli (CCT-1457). O objetivo deste estudo foi avaliar o poder de desinfecção e o comportamento cinético da eletrólise realizada em reator de compartimento único e usando eletrodos ADE (Anodo Dimensionalmente Estável), visando ampliação de escala. Uma suspensão contendo elevada concentração de E. coli (10(6) UFC mL-1) foi submetida ao tratamento no reator em 25, 50 e 75 mA cm-2 durante 60 min, em vazões de 200 e 50 Lh-1. A taxa de inativação foi aproximadamente 99 por cento para a solução isenta de compostos clorados, com consumo de energia elétrica menor que 5,60 kWh m-3 em 200 L h-1 e 75 mA cm-2. Uma solução de Na2SO4 0,08M eletrolisada e adicionada posteriormente ao inoculo apresentou efeito residual bactericida. A eficiência da desinfecção foi regida pelo tempo de contato e pela densidade de corrente aplicada, e foi realizado um estudo cinético que permite a ampliação de escala.