RESUMO
Trigonella foenum-graecum, known as fenugreek, belongs to the leguminous family of wild growth in Western Asia, Europe, the Mediterranean, and Asia; its ripe seeds contain a pool of bioactive substances with great potential in the food industry and medicine. In this study, fenugreek seed mucilage (FSM) was extracted and characterized in its structural properties by X-ray diffraction, nuclear magnetic resonance, and high-performance liquid chromatography. Then, the applicability of FSM as an antimicrobial agent was demonstrated via the development of novel, active, edible FSM-based biofilms containing carboxymethyl cellulose and rosemary essential oil (REO). Incorporating REO in the biofilms brought about specific changes in Fourier-transform infrared spectra, affecting thermal degradation behavior. Scanning electron microscopy and atomic force microscopy morphography showed an even distribution of REO and smoother surfaces in the loaded films. Besides, the solubility tests evidenced a reduction in water solubility with increasing REO concentration from 1 to 3 wt%. The biological assay evidenced the antimicrobial activity of REO-loaded biofilms against Staphylococcus aureus and Escherichia coli. Finally, whole apples were dip-coated with FSM-based solutions to showcase future edible systems. The REO-loaded biofilms extended the shelf life of apples to 30 days, demonstrating their potential for sustainable and active coatings.
Assuntos
Anti-Infecciosos , Filmes Comestíveis , Frutas , Sementes , Trigonella , Trigonella/química , Frutas/química , Sementes/química , Anti-Infecciosos/farmacologia , Anti-Infecciosos/química , Mucilagem Vegetal/química , Biofilmes/efeitos dos fármacos , Staphylococcus aureus/efeitos dos fármacos , Escherichia coli/efeitos dos fármacos , Fenômenos Químicos , Solubilidade , Armazenamento de Alimentos , Antibacterianos/farmacologia , Antibacterianos/química , Testes de Sensibilidade MicrobianaRESUMO
In this study, the potential of bagasse pith (the waste of sugar and paper industry) was investigated for bio-xylitol production for the first time. Xylose-rich hydrolysate was prepared using 8% dilute sulfuric acid, at 120 °C for 90 min. Then, the acid-hydrolyzed solution was detoxified by individual overliming (OL), active carbon (AC), and their combination (OL+AC). The amounts of reducing sugars and inhibitors (furfural and hydroxyl methyl furfural) were measured after acid pre-treatment and detoxification process. Thereafter, xylitol was produced from detoxified hydrolysate by Rhodotorula mucilaginosa yeast. Results showed that after acid hydrolysis, the sugar yield was 20%. Detoxification by overliming and active carbon methods increased the reducing sugar content up to 65% and 36% and decreased the concentration of inhibitors to >90% and 16%, respectively. Also, combined detoxification caused an increase in the reducing sugar content (>73%) and a complete removal of inhibitors. The highest productivity of xylitol (0.366 g/g) by yeast was attained after the addition of 100 g/l non-detoxified xylose-rich hydrolysate into fermentation broth after 96 h, while the xylitol productivity enhanced to 0.496 g/g after adding the similar amount of xylose-rich hydrolysate detoxified by combined method (OL+AC2.5%).
Assuntos
Celulose , Rhodotorula , Xilitol , Xilose , Furaldeído , Leveduras , Carvão Vegetal , Fermentação , HidróliseRESUMO
In the present study, the effect of zein and different amounts of bacterial cellulose (BC; 1, 2 and 3 wt%) on the physical, mechanical and barrier properties of flaxseed mucilage/carboxymethyl cellulose (FM/CMC) composite was investigated. The appearance of the absorption band at 1320cm-1 in the ATR-FTIR spectra of nanocomposites indicated the successful introduction of zein into their structure. The characteristic peak at 2θ of 9° belonging to zein disappeared in XRD patterns of the prepared composites suggesting the successful coating of zein via hydrogen bonding interactions. SEM images proved the formation of semi-spherical zein microparticles in the FM/CMC matrix. TGA plots ascertained the addition of zein and nanocellulose caused a significant increase in the thermal stability of FM/CMC film, although zein showed a greater effect. The presence of zein and nanocellulose increased the mechanical strength of nanocomposites. The WVP of FM/CMC decreased after the incorporation of zein and nanocellulose, which created a tortuous path for the diffusion of water molecules. The zein particles exhibited a greater influence on improving the mechanical and barrier properties compared to nanocellulose. FM/CMC-Z film exhibited the highest mechanical strength (49.07 ± 5.89 MPa) and the lowest WVP (1.179 ± 0.076). The composites containing oregano essential oil (EO) showed higher than 60 % antibacterial properties. The bactericidal efficiency of FM/CMC/Z-EO and FM/CMC/Z-EO/BC1 nanocomposites decreased about 10% compared to FM/CMC/EO and FM/CMC-Z/BC1. This evidenced the successful encapsulation of EO molecules in zein particles. According to the in vitro release study, entrapment of EO into zein particles could delay the release and provide the extended antimicrobial effect.
Assuntos
Linho , Nanocompostos , Óleos Voláteis , Origanum , Zeína , Celulose/química , Óleos Voláteis/farmacologia , Óleos Voláteis/química , Zeína/química , Óleo de Semente do Linho , Polissacarídeos , Nanocompostos/químicaRESUMO
This study presents the development and characterization of a nanocomposite material, consisting of thermoplastic starch (TPS) reinforced with bentonite clay (BC) and encapsulated with vitamin B2 (VB). The research is motivated by the potential of TPS as a renewable and biodegradable substitute for petroleum-based materials in the biopolymer industry. The effects of VB on the physicochemical properties of TPS/BC films, including mechanical and thermal properties, water uptake, and weight loss in water, were investigated. In addition, the surface morphology and chemical composition of the TPS samples were analyzed using high-resolution SEM microscopy and EDS, providing insight into the structure-property relationship of the nanocomposites. The results showed that the addition of VB significantly increased the tensile strength and Young's modulus of TPS/BC films, with the highest values observed for nanocomposites containing 5 php of VB and 3 php of BC. Furthermore, the release of VB was controlled by the BC content, with higher BC content leading to lower VB release. These findings demonstrate the potential of TPS/BC/VB nanocomposites as environmentally friendly materials with improved mechanical properties and controlled release of VB, which can have significant applications in the biopolymer industry.
Assuntos
Nanocompostos , Amido , Amido/química , Bentonita/química , Argila , Riboflavina , Resistência à Tração , Nanocompostos/química , Água , VitaminasRESUMO
A safe drug carrier was synthesized by albumin (BSA) and oxidized gum arabic (OGA). Piperine (PIP) was loaded into BSA/OGA nanobiocomposites by desolvation method. A set of experiments were designed by considering different contents of OGA (5, 7.5 and 10 mg) and PIP (1 and 2 mg). The presence of the band at 1600-1660 cm-1 in FTIR spectra revealed the successful interaction between OGA and BSA. PIP2-BSA/OGA5 was selected as a suitable carrier due to its smaller size (<300 nm) and higher loading efficiency (1.5 ± 0.2 %). The encapsulation efficiency of PIP into BSA/OGA5 was 57.6 ± 2 %. The average size, polydispersity index and zeta potential of PIP2-BSA/OGA5 were 292 ± 4.4 nm, 0.185 ± 0.03 and - 24.4 ± 1.7 mV, respectively. SEM and TEM images proved the formation of spherical-shaped nanoparticles. The disappearance of endothermic peak belonging to free PIP in DSC thermogram of PIP2-BSA/OGA5 evidenced its encapsulation into carrier. PIP2-BSA/OGA5 exhibited the sustained drug release. The cell viability of MCF-7 cells after 48 h exposure to BSA/OGA5, PIP2-BSA/OGA5 and free PIP was reported 90 %, 40.1 % and 30.6 %, respectively. The molecular docking study reported that the binding affinity of PIP for BSA/OGA nanocomposite was -8.7 kcal/mol indicating the acceptable stability of the prepared drug carrier.
Assuntos
Nanopartículas , Soroalbumina Bovina , Simulação de Acoplamento Molecular , Soroalbumina Bovina/química , Goma Arábica , Preparações de Ação Retardada , Portadores de Fármacos/química , Concentração de Íons de Hidrogênio , Nanopartículas/química , Tamanho da PartículaRESUMO
The purpose of the present article is to study the bending strength of glulam prepared by plane tree (Platanus Orientalis-L) wood layers adhered by UF resin with different formaldehyde to urea molar ratios containing the modified starch adhesive with different NaOCl concentrations. Artificial neural network (ANN) as a modern tool was used to predict this response, too. The multilayer perceptron (MLP) models were used to predict the modulus of rapture (MOR) and the statistics, including the determination coefficient (R2), root mean square error (RMSE), and mean absolute percentage error (MAPE) were used to validate the prediction. Combining the ANN and the genetic algorithm by using the multiple objective and nonlinear constraint functions, the optimum point was determined based on the experimental and estimated data, respectively. The characterization analysis, performed by FTIR and XRD, was used to describe the effect of the inputs on the output. The results indicated that the statistics obtained show excellent MOR predictions by the feed-forward neural network using Levenberg-Marquardt algorithms. The comparison of the optimal output of the actual values obtained by the genetic algorithm resulting from the multi-objective function and the optimal output of the values estimated by the nonlinear constraint function indicates a minimum difference between both functions.
RESUMO
Chitosan/PVA hydrogel films crosslinked by the freeze-thaw method and containing honey and allantoin were prepared for application as wound dressing materials. The effects of the freeze-thaw process and the addition of honey and allantoin on the swelling, the gel content and the mechanical properties of the samples were evaluated. The physicochemical properties of the samples, with and without the freeze-thaw process, were compared using FTIR, DSC and XRD. The results showed that the freeze-thaw process can increase the crystallinity and thermal stability of chitosan/PVA films. The freeze-thaw process increased the gel content but did not have a significant effect on the tensile strength. The presence of honey reduced the swelling and the tensile strength of the hydrogels due to hydrogen bonding interactions with PVA and chitosan chains. Long-term cell culture experiments using normal human dermal fibroblast (NHDF) cells showed that the hydrogels maintained their biocompatibility, and the cells showed extended morphology on the surface of the hydrogels for more than 30 days. The presence of honey significantly increased the biocompatibility of the hydrogels. The release of allantoin from the hydrogel was studied and, according to the Korsmeyer-Peppas and Weibull models, the mechanism was mainly diffusional. The results for the antimicrobial activity against E. coli and S. aureus bacteria showed that the allantoin-containing samples had a more remarkable antibacterial activity against S. aureus. According to the wound healing experiments, 98% of the wound area treated by the chitosan/PVA/honey hydrogel was closed, compared to 89% for the control. The results of this study suggest that the freeze-thaw process is a non-toxic crosslinking method for the preparation of chitosan/PVA hydrogels with long term biocompatibility that can be applied for wound healing and skin tissue engineering.
RESUMO
In this research a bench scale rotating biological contactor (RBC) was designed and constructed to produce BC. The effects of variables including rotation speed of the disk, distance between disks, disk type and external aeration on BC productivity were investigated. Results showed that the highest weight of BC produced on the surface of integrated polyethylene discs which rotated at 13 rpm. It was also found that the highest amount of BC was obtained when the space between two adjacent discs was adjusted to 1 cm and the disk number was 16. An aquarium pump was used to investigate the impact of aeration on RBC made of 12 integrated polyethylene discs and operated at optimal rotation speed of 13 rpm. Disk spacing distance was adjusted to 1.5 cm to consider the possible increasing of the thickness of BC film by aeration. Wet weight and dry weight of BC resulted from aerated fermentation increased more than 64 and 47%, respectively as compared to non-aerated RBC. In comparison with static culture, wet weight and dry weight of BC produced in aerated RBC fermentation increased more than 90.7 and 71%, respectively. Nanoscale structure of produced bacterial cellulose was confirmed by SEM analysis.
Assuntos
Reatores Biológicos , Celulose/biossíntese , Gluconacetobacter xylinus/crescimento & desenvolvimentoRESUMO
This study was aimed to design a novel amphiphilic carrier based on schizophyllan (SPG) exopolysacharide for drug delivery. Stearic acid (SA) was used for the esterification of SPG with two degrees of substitutions (SA-SPG0.5 and SA-SPG1). The H NMR and FTIR spectroscopies verified the succesfull esterification of SPG. The polymeric micelles easily self-assembled into nanomicelles by ultrasound method. Fluorescence spectroscopy showed that the critical micelle concentrations (CMCs) of SA-SPG0.5 and SA-SPG1 micelles were 0.068 mg/mL and 0.027 mg/mL, respectively. DLS analyses showed that nanomicelles were ranged from 156 to 175 nm. SEM and TEM images showed that nanomicelles were mostly spherical. Paclitaxel (PTX) as a drug model was successfully loaded into SA-SPG nanomicelles with three different drug/polymer weight ratios of 0.1, 0.2 and 0.3. The highest encapsulation efficiency (75 %) was obtained when the PTX/SA-SPG weight ratio was 0.1. The in vitro release of PTX from SA-SPG micelles represented the sustained release profile over 144 h. MTT assay showed that the PTX-loaded SA-SPG nanomicelles had the higher cytotoxicity against MCF-7 cells than free PTX. These results revealed that the synthesized SA-SPG nanomicelles had a promising potential as a new carrier for efficient delivery of hydrophobic drugs.
Assuntos
Micelas , Sizofirano , Portadores de Fármacos , Humanos , Paclitaxel/farmacologia , Ácidos EsteáricosRESUMO
In this study, the antibacterial polyelectrolyte carboxymethyl xylan/chitosan (CMX/CS) films incorporated with halloysite nanotubes (HNTs) and Origanum vulgare essential oil (OEO) were prepared and then characterized. Xylan-rich hemicelluloses (62.23%) were extracted from sugarcane bagasse pith and then subjected to carboxymethylation. FTIR analysis revealed the successful modification of hemicelluloses. The irregular white spots in SEM images of nanobiocomposites revealed the entrance of HNTs into the polymer matrix. EDX maps manifested that the density of Si and Al atoms increased, as the amount of HNT increased. The observed discontinuities for EO-containing nanobiocomposites in the SEM images may be attributed to the hydrophobic nature of EO. The barrier properties of the nanocomposites improved by incorporation of HNTs and O. vulgare. The tensile strength of nanocomposite improved significantly by incorporating HNT. EO/HNT-containing films exhibited a higher antibacterial activity against selected bacteria than HNT-containing films.
Assuntos
Antibacterianos/química , Celulose/química , Argila/química , Nanocompostos/química , Nanotubos/química , Xilanos/química , Materiais Biocompatíveis/química , Quitosana/análogos & derivados , Quitosana/química , Interações Hidrofóbicas e Hidrofílicas , Óleos Voláteis/química , Origanum/química , Polímeros/química , Resistência à TraçãoRESUMO
In this study, a novel hydrogel composed of bacterial cellulose (BC) and schizophyllan (SPG) biopolymers with improved mechanical, swelling and antibacterial properties was developed. BC was firstly functionalized using 3-aminopropyl triethoxysilane (APTES) to provide better interaction with SPG. A diffraction peak at 5.7° in the XRD pattern of amine-grafted BC/SPG membrane revealed the intercalation of SPG into BC network. SEM images of amine-grafted BC/SPG showed that the fibrillar network of BC was totally covered with schizophyllan. Two distinct stages of weight loss in TGA thermo-gram of amine grafted BC/SPG verified the successful entrance of SPG into BC fibrils. Tensile strength of the amine-grafted BC/SPG considerably increased to 42.19⯱â¯7.16â¯MPa as compared to neat BC (4.41 ± 0.38â¯MPa) and amine-grafted BC (7.90⯱â¯0.71â¯MPa). It also showed the highest swelling degree (800⯱â¯80%). Amine-grafted BC/SPG exhibited moderate antibacterial activity. MTT assay showed that amine-grafted BC/SPG stimulated the proliferation of normal human fibroblast cells.
Assuntos
Antibacterianos/química , Celulose/química , Hidrogéis/química , Sizofirano/química , Aminação , Antibacterianos/farmacologia , Linhagem Celular , Sobrevivência Celular/efeitos dos fármacos , Celulose/farmacologia , Escherichia coli/efeitos dos fármacos , Escherichia coli/crescimento & desenvolvimento , Fibroblastos/efeitos dos fármacos , Humanos , Hidrogéis/farmacologia , Schizophyllum/metabolismo , Sizofirano/metabolismo , Sizofirano/farmacologia , Staphylococcus aureus/efeitos dos fármacos , Staphylococcus aureus/crescimento & desenvolvimentoRESUMO
The potential of Mentha piperita in the iron nanoparticles (FeNPs) production was evaluated for the first time. The influences of the variables such as incubation time, temperature, and volume ratio of the extract to metal ions on the nanoparticle size were investigated using central composite design. The appearance of SPR bands at 284â nm in UV-Vis spectra of the mixtures verified the nanoparticle formation. Incubating the aqueous extract and metal precursor with 1.5 volume ratio at 50°C for 30â min leads to the formation of the smallest nanoparticles with the narrowest size distribution. At the optimal condition, the nanoparticles were found to be within the range of 35-50â nm. Experimental measurements of the average nanoparticle size were fitted well to the polynomial model satisfactory with R2 of 0.9078. Among all model terms, the linear term of temperature, the quadratic terms of temperature, and mixing volume ratio have the significant effects on the nanoparticle average size. FeNPs produced at the optimal condition were characterised by transmission electron microscopy, thermogravimetry analysis (TGA), and Fourier-transform infrared spectroscopy. The observed weight loss in the TGA curve confirms the encapsulation of FeNPs by the biomolecules of the extract which were dissociated by heat.
Assuntos
Química Verde/métodos , Nanopartículas de Magnetita/química , Mentha piperita/química , Extratos Vegetais/química , Microscopia Eletrônica de Transmissão , Tamanho da Partícula , Espectroscopia de Infravermelho com Transformada de FourierRESUMO
In this study, biological properties of the essential oil isolated from seeds of Foeniculum vulgare (F. vulgare) were evaluated. GC-MS analysis revealed Trans-Anethole (80.63%), L-Fenchone (11.57%), Estragole (3.67%) and Limonene (2.68%) were the major compounds of the essential oil. Antibacterial activity of the essential oil against nine Gram-positive and Gram-negative strains was studied using disc diffusion and micro-well dilution assays. Essential oil exhibited the antibacterial activity against three Gram-negative strains of Pseudomonas aeruginosa, Escherichia coli, and Shigella dysenteriae. The preliminary study on toxicity of seed oil was performed using Brine Shrimp lethality test (BSLT). Results indicated the high toxicity effect of essential oil (LC50 = 10 µg/mL). In vitro anticancer activity of seed oil was investigated against human breast cancer (MDA-Mb) and cervical epithelioid carcinoma (Hela) cell lines by MTT assay. Results showed the seed oil behave as a very potent anticancer agent with IC50 of lower than 10 µg/mL in both cases.
Assuntos
Antibacterianos/farmacologia , Antineoplásicos Fitogênicos/farmacologia , Foeniculum/química , Óleos Voláteis/farmacologia , Derivados de Alilbenzenos , Animais , Anisóis/análise , Artemia/efeitos dos fármacos , Linhagem Celular Tumoral , Cromatografia Gasosa-Espectrometria de Massas/métodos , Bactérias Gram-Negativas/efeitos dos fármacos , Humanos , Irã (Geográfico) , Óleos Voláteis/análise , Óleos Voláteis/isolamento & purificação , Óleos de Plantas/análise , Óleos de Plantas/farmacologia , Testes de ToxicidadeRESUMO
In this study, the efficiencies of conventional hydro-distillation and novel microwave hydro-distillation methods in extraction of essential oil from Rosemary officinalis leaves have been compared. In order to attain the best yield and also highest quality of the essential oil in the microwave assisted method, the optimal values of operating parameters such as extraction time, microwave irradiation power and water volume to plant mass ratio were investigated using central composite design under response surface methodology. Optimal conditions for obtaining the maximum extraction yield in the microwave assisted method were predicted as follows: extraction time of 85 min, microwave power of 888 W, and water volume to plant mass ratio of 0.5 ml/g. The extraction yield at these predicted conditions was computed as 0.7756%. The qualities of the obtained essential oils under designed experiments were optimized based on total contents of four major compounds (α-pinene, 1,8-cineole, camphor and verbenone) which determined by gas chromatography equipped with mass spectroscopy (GC-MS). The highest essential oil quality (55.87%) was obtained at extraction time of 68 min; microwave irradiation power of 700 W; and water volume to plant mass ratio of zero.
RESUMO
In the present study, chemical composition of the oily compounds isolated from different parts of Smirnovia turkestana (Kashan, central Iran) using n-hexane was determined for the first time. GC-MS analysis revealed that dodecanoic acid, trans-ß-ionone and methyl palmitate are the major components of leaves extract. Trans-ß-ionone and hexadodecanoic acid were also, identified as the major compounds of flowers extract. Heptacosane, trans-ß-ionone and vitamin E acetate were the main components of fruits. Phytochemical screening of the methanol extract proved the presence of alkaloids, anthraquinones, flavonoids and anthocyanin in the leaves, flowers and fruits of S. turkestana, while tannins were present only in its fruits. Evaluation of the biological activities showed that different aerial parts of S. turkestana have high antioxidant activities; antimicrobial activities were also considerable against some selected bacteria.
Assuntos
Antibacterianos/farmacologia , Antioxidantes/farmacologia , Fabaceae/química , Óleos Voláteis/farmacologia , Componentes Aéreos da Planta/química , Extratos Vegetais/farmacologia , Alcaloides/química , Antocianinas/química , Antraquinonas/química , Antibacterianos/química , Antioxidantes/química , Bactérias/efeitos dos fármacos , Flavonoides/química , Cromatografia Gasosa-Espectrometria de Massas , Irã (Geográfico) , Óleos Voláteis/química , Compostos Fitoquímicos/química , Compostos Fitoquímicos/farmacologia , Extratos Vegetais/química , Folhas de Planta/química , Taninos/químicaRESUMO
Elucidation of the molecular mechanism of silver nanoparticle (AgNP) synthesis is necessary to control nanoparticle size, shape, and monodispersity. In this study, the mechanism of AgNP formation by Neurospora intermedia was investigated. The higher production rate of AgNP formation using a culture supernatant heat-treated at 100° and 121°C relative to that with an un-treated culture supernatant indicated that the native form of the molecular species is not essential. The effect of the protein molecular weight (MW) on the nanoparticle size distribution and average size was studied by means of ultraviolet-visible spectroscopy and dynamic light scattering. Using un-treated and concentrated cell-free filtrate passed through 10 and 20â kDa cut-off filters led to the production of AgNPs with average sizes of 25, 30, and 34â nm, respectively. Also, using the permeate fraction of cell-free filtrate passed through a 100â kDa cut-off filter led to the formation of the smallest nanoparticles with the narrowest size distribution (average size of 16â nm and polydispersity index of 0.18). Sodium dodecyl sulphate polyacrylamide gel electrophoresis analysis of the fungal extracellular proteins showed two notable bands with the MWs of 15 and 23â kDa that are involved in the reduction and stabilisation of the nanoparticles, respectively.
Assuntos
Produtos Biológicos/metabolismo , Nanopartículas/química , Nanopartículas/ultraestrutura , Neurospora/metabolismo , Prata/química , Prata/metabolismo , Produtos Biológicos/síntese química , Sistema Livre de Células , Teste de Materiais , Neurospora/química , Neurospora/classificação , Tamanho da Partícula , Especificidade da Espécie , Propriedades de SuperfícieRESUMO
In this study, a rapid green synthesis of the silver nanoparticles (AgNPs) using leaves extract of Convolvulus arvensis was investigated. UV-Visible spectra showed the SPR band at around 430nm which proved the AgNP formation. The reduction of silver ions to nanoparticles was completed within 150min. Particle size analysis verified the formation of AgNPs with average size of 28nm, while their PDI was 0.2. XRD patterns verified the crystalline nature of produced AgNPs. SEM images verified the presence of spherical nanoparticles with no evidence of aggregations. FTIR analysis verified the involvement of the phenolic compounds in AgNP formation. It was found that the biosynthesized AgNPs have the antibacterial activity against human pathogen E. coli. Also, nanoparticles exhibit biofilm degrading activity against both bacterial strains of S. aureus and P. aeruginosa. Furthermore, the synthesized AgNPs prevented the coagulation of blood samples. The accelerated reduction of methylene blue (MB) in the presence of AgNPs with rate constant of 0.108min-1, confirmed the catalytic potential of nanoparticles.
Assuntos
Antibacterianos/farmacologia , Biofilmes/efeitos dos fármacos , Convolvulus/química , Nanopartículas Metálicas/química , Extratos Vegetais/farmacologia , Prata/química , Catálise , Humanos , Testes de Sensibilidade Microbiana , Microscopia Eletrônica de Varredura , Extratos Vegetais/química , Pseudomonas aeruginosa/efeitos dos fármacos , Análise Espectral , Staphylococcus aureus/efeitos dos fármacos , Difração de Raios XRESUMO
The controlled synthesis of silver nanoparticles (AgNPs) using cell-free filtrate of Fusarium oxysporum fungus was investigated. The effect of fungal incubation period on nanoparticle formation and nitrate reductase enzyme activity was studied using UV-visible spectroscopy and Harley assay, respectively. The highest AgNP formation was observed in the cell-free filtrate of biomass harvested at the early stationary phase where the NR enzyme activity is the maximum. Mixing of the cell-free filtrates of fungal cultures obtained at 23, 28, and 33 °C with silver nitrate solution confirms the higher productivity of AgNP biosynthesis using the cell-free filtrate of fungus incubated at 28 °C. The effect of some factors such as carbon and nitrate sources and light in fungal incubation period on nitrate reductase induction and AgNP formation was also evaluated. In conclusion, increasing nitrate and carbon sources and presence of light induced NR enzyme and produced AgNPs with smaller size, higher monodispersity, and productivity. Results revealed that the presence of ammonium prevents the NR enzyme secretion and causes to the lower productivity of AgNPs.
Assuntos
Antibacterianos/metabolismo , Antibacterianos/farmacologia , Fusarium/metabolismo , Nanopartículas Metálicas/química , Nitrato Redutase/biossíntese , Prata/metabolismo , Prata/farmacologia , Antibacterianos/química , Carbono/farmacologia , Indução Enzimática/efeitos dos fármacos , Indução Enzimática/efeitos da radiação , Fusarium/efeitos dos fármacos , Fusarium/enzimologia , Fusarium/efeitos da radiação , Luz , Testes de Sensibilidade Microbiana , Prata/química , TemperaturaRESUMO
In the present study the effect of process (homogenization speed) and formulation (polymer-alginate-concentration, surfactant concentration, drug amount, perfluorohexane volume fraction and co-surfactant inclusion) variables on particle size, entrapment efficiency, and drug release kinetics of doxorubicin-loaded alginate stabilized perfluorohexane nanodroplets were evaluated. Particle size and doxorubicin entrapment efficiency were highly affected by formulation and process variables. Increase in homogenization speed resulted in significant decrease in particle size and increase in entrapment efficiency. Polymer concentration and perfluorohexane amount both had similar effect on particle size. Particle size increased by an increase in the amount of both. Entrapment efficiency increased by increasing polymer concentration. In case of surfactant concentration and drug amount, particle size and entrapment efficiency had optimum values and an increase in concentration of both of them behind a certain limit resulted in increase in particle size and decrease in doxorubicin entrapment. In vitro release profile of doxorubicin was an apparently biphasic release process and 7%-13% of drug released after 24h incubation in PBS, pH=7.4, depending on the nanodroplets composition but ultrasound exposure for 10min resulted in triggered release of 85.95% of doxorubicin from optimal formulation (formulation E1 with 39.2nm diameter size and 92.2% entrapment efficiency).
Assuntos
Alginatos/química , Doxorrubicina/química , Nanopartículas/química , Neoplasias/tratamento farmacológico , Alginatos/administração & dosagem , Linhagem Celular Tumoral , Preparações de Ação Retardada , Doxorrubicina/administração & dosagem , Portadores de Fármacos , Ácido Glucurônico/administração & dosagem , Ácido Glucurônico/química , Ácidos Hexurônicos/administração & dosagem , Ácidos Hexurônicos/química , Humanos , Nanopartículas/administração & dosagem , Tamanho da Partícula , Polímeros/química , Tensoativos/químicaRESUMO
In the present study, the biosynthesis of silver nanoparticles (AgNPs) using Neurospora intermedia, as a new non-pathogenic fungus was investigated. For determination of biomass harvesting time, the effect of fungal incubation period on nanoparticle formation was investigated using UV-visible spectroscopy. Then, AgNPs were synthesized using both culture supernatant and cell-free filtrate of the fungus. Two different volume ratios (1:100 and 1:1) of the culture supernatant to the silver nitrate were employed for AgNP synthesis. In addition, cell-free filtrate and silver nitrate were mixed in presence and absence of light. Smallest average size and highest productivity were obtained when using equal volumes of the culture supernatant and silver nitrate solution as confirmed by UV-visible spectra of colloidal AgNPs. Comparing the UV-visible spectra revealed that using cell-free filtrate for AgNP synthesis resulted in the formation of particles with higher stability and monodispersity than using culture supernatant. The absence of light in cell-free filtrate mediated synthesis led to the formation of nanoparticles with the lowest rate and the highest monodispersity. The presence of elemental silver in all prepared samples was confirmed using EDX, while the crystalline nature of synthesized particles was verified by XRD. FTIR results showed the presence of functional groups which reduce Ag(+) and stabilize AgNPs. The presence of nitrate reductase was confirmed in the cell-free filtrate of the fungus suggesting the potential role of this enzyme in AgNP synthesis. Synthesized particles showed significant antibacterial activity against E. coli as confirmed by examining the growth curve of bacterial cells exposed to AgNPs.