In this study, antibacterial characteristic of silver/poly (lactic acid) nanocomposite (Ag/PLA-NC) films was investigated, while silver nanoparticles (Ag-NPs) were synthesized into biodegradable PLA via chemical reduction method in diphase solvent. Silver nitrate and sodium borohydride were respectively used as a silver precursor and reducing agent in the PLA, which acted as a polymeric matrix and stabilizer. Meanwhile, the properties of Ag/PLA-NCs were studied as a function of the Ag-NP weight percentages (8, 16, and 32 wt% respectively), in relation to the use of PLA. The morphology of the Ag/PLA-NC films and the distribution of the Ag-NPs were also characterized. The silver ions released from the Ag/PLA-NC films and their antibacterial activities were scrutinized. The antibacterial activities of the Ag/PLA-NC films were examined against Gram-negative bacteria (Escherichia coli and Vibrio parahaemolyticus) and Gram-positive bacteria (Staphylococcus aureus) by diffusion method using Muller-Hinton agar. The results indicated that Ag/PLA-NC films possessed a strong antibacterial activity with the increase in the percentage of Ag-NPs in the PLA. Thus, Ag/PLA-NC films can be used as an antibacterial scaffold for tissue engineering and medical application.
In this study, silver nanoparticles (Ag-NPs) were synthesized using a green physical synthetic route into the lamellar space of montmorillonite (MMT)/chitosan (Cts) utilizing the ultraviolet (UV) irradiation reduction method in the absence of any reducing agent or heat treatment. Cts, MMT, and AgNO(3) were used as the natural polymeric stabilizer, solid support, and silver precursor, respectively. The properties of Ag/MMT/Cts bionanocomposites (BNCs) were studied as the function of UV irradiation times. UV irradiation disintegrated the Ag-NPs into smaller sizes until a relatively stable size and size distribution were achieved. Meanwhile, the crystalline structure and d-spacing of the MMT interlayer, average size and size distribution, surface morphology, elemental signal peaks, functional groups, and surface plasmon resonance of Ag/MMT/Cts BNCs were determined by powder X-ray diffraction, transmission electron microscopy, scanning electron microscopy, energy dispersive X-ray fluorescence, Fourier transform infrared, and UV-visible spectroscopy. The antibacterial activity of Ag-NPs in MMT/Cts was investigated against Gram-positive bacteria, ie, Staphylococcus aureus and methicillin-resistant S. aureus and Gram-negative bacteria (ie, Escherichia coli) by the disk diffusion method on Muller-Hinton Agar at different sizes of Ag-NPs. All of the synthesized Ag/MMT/Cts BNCs were found to have high antibacterial activity. These results show that Ag/MMT/Cts BNCs can be useful in different biologic research and biomedical applications, such as surgical devices and drug delivery vehicles.
Silver nanoparticles (Ag-NPs) were synthesized into the interlamellar space of montmorillonite (MMT) by using the γ-irradiation technique in the absence of any reducing agent or heat treatment. Silver nitrate and γ-irradiation were used as the silver precursor and physical reducing agent in MMT as a solid support. The MMT was suspended in the aqueous AgNO(3) solution, and after the absorption of silver ions, Ag(+) was reduced using the γ-irradiation technique. The properties of Ag/MMT nanocomposites and the diameters of Ag-NPs were studied as a function of γ-irradiation doses. The interlamellar space limited particle growth (d-spacing [d(s)] = 1.24-1.42 nm); powder X-ray diffraction and transmission electron microscopy (TEM) measurements showed the production of face-centered cubic Ag-NPs with a mean diameter of about 21.57-30.63 nm. Scanning electron microscopy images indicated that there were structure changes between the initial MMT and Ag/MMT nanocomposites under the increased doses of γ-irradiation. Furthermore, energy dispersive X-ray fluorescence spectra for the MMT and Ag/ MMT nanocomposites confirmed the presence of elemental compounds in MMT and Ag-NPs. The results from ultraviolet-visible spectroscopy and TEM demonstrated that increasing the γ-irradiation dose enhanced the concentration of Ag-NPs. In addition, the particle size of the Ag-NPs gradually increased from 1 to 20 kGy. When the γ-irradiation dose increased from 20 to 40 kGy, the particle diameters decreased suddenly as a result of the induced fragmentation of Ag-NPs. Thus, Fourier transform infrared spectroscopy suggested that the interactions between Ag-NPs with the surface of MMT were weak due to the presence of van der Waals interactions. The synthesized Ag/MMT suspension was found to be stable over a long period of time (ie, more than 3 months) without any sign of precipitation.
Silver nanoparticles (Ag-NPs) were successfully synthesized in the natural polymeric matrix. Silver nitrate, gelatin, glucose, and sodium hydroxide have been used as silver precursor, stabilizer, reducing agent, and accelerator reagent, respectively. This study investigated the role of NaOH as the accelerator. The resultant products have been confirmed to be Ag-NPs using powder X-ray diffraction (PXRD), UV-vis spectroscopy, and transmission electron microscopy (TEM). The colloidal sols of Ag-NPs obtained at different volumes of NaOH show strong and different surface plasmon resonance (SPR) peaks, which can be explained from the TEM images of Ag-NPs and their particle size distribution. Compared with other synthetic methods, this work is green, rapid, and simple to use. The newly prepared Ag-NPs may have many potential applications in chemical and biological industries.
In this study we used a laser ablation technique for preparation of silver nanoparticles. The fabrication process was carried out by ablation of a silver plate immersed in palm oil. A pulsed Nd:YAG laser at a wavelength of 1064 nm was used for ablation of the plate at different times. The palm coconut oil allowed formation of nanoparticles with very small and uniform particle size, which are dispersed very homogeneously within the solution. The obtained particle sizes for 15 and 30 minute ablation times were 2.5 and 2 nm, respectively. Stability study shows that all of the samples remained stable for a reasonable period of time.
In this study, silver nanoparticles (Ag-NPs) were synthesized using the wet chemical reduction method on the external surface layer of talc mineral as a solid support. Silver nitrate and sodium borohydride were used as the silver precursor and reducing agent in talc. The talc was suspended in aqueous AgNO(3) solution. After the absorption of Ag(+) on the surface, the ions were reduced with NaBH(4). The interlamellar space limits were without many changes (d(s) = 9.34-9.19 A(º)); therefore, Ag-NPs formed on the exterior surface of talc, with d(ave) = 7.60-13.11 nm in diameter. The properties of Ag/talc nanocomposites (Ag/talc-NCs) and the diameters of the Ag-NPs prepared in this way depended on the primary AgNO(3) concentration. The prepared Ag-NPs were characterized by ultraviolet-visible spectroscopy, powder X-ray diffraction, transmission electron microscopy, scanning electron microscopy, and Fourier transform infrared. These Ag/talc-NCs may have potential applications in the chemical and biological industries.
Full-thickness burn wounds require excision and skin grafting. Multiple surgical procedures are inevitable in managing moderate to severe full-thickness burns. Wound bed preparations prior to surgery are necessary in order to prevent wound infection and promote wound healing. Honey can be used to treat burn wounds. However, not all the honey is the same. This study aims to evaluate the wound contraction and antibacterial properties of locally-produced Tualang honey on managing full-thickness burn wounds in vivo.
Different biological methods are gaining recognition for the production of silver nanoparticles (Ag-NPs) due to their multiple applications. One of the most important applications of Ag-NPs is their use as an anti-bacterial agent. The use of plants in the synthesis of nanoparticles emerges as a cost effective and eco-friendly approach. In this study the biosynthesis of silver nanoparticles using Vitex negundo L. extract and its antimicrobial properties has been reported. The resulting silver particles are characterized using transmission electron microscopy (TEM), X-ray diffraction (XRD) and UV-Visible (UV-Vis) spectroscopic techniques. The TEM study showed the formation of silver nanoparticles in the 10-30 nm range and average 18.2 nm in size. The XRD study showed that the particles are crystalline in nature, with a face centered cubic (fcc) structure. The silver nanoparticles showed the antimicrobial activity against Gram positive and Gram negative bacteria. Vitex negundo L. was found to display strong potential for the synthesis of silver nanoparticles as antimicrobial agents by rapid reduction of silver ions (Ag+ to Ag0).
In this research, silver nanoparticles (AgNPs) were synthesized in chitosan (Cts), Cts/gelatin and gelatin suspensions using a chemical reducing agent. Cts and gelatin were used as natural stabilizers and solid support, whereas AgNO(3) was used as the silver precursor. Sodium borohydride (NaBH(4)) was used as the reducing agent. The properties of AgNPs in Cts, Cts/gelatin and gelatin bionanocomposites (BNCs) were studied in terms of their surface plasmon resonance, crystalline structure, average diameter size, particle distributions, surface topography and functional groups. All the samples were characterized by UV-visible spectroscopy, powder X-ray diffraction, transmission electron microscopy, atomic force microscopy and Fourier transform infrared spectroscopy.
Silver nanoparticles (Ag-NPs) were successfully synthesized using the UV irradiation of aqueous solutions containing AgNO(3) and gelatin as a silver source and stabilizer, respectively. The UV irradiation times influence the particles' diameter of the Ag-NPs, as evidenced from surface plasmon resonance (SPR) bands and transmission electron microscopy (TEM) images. When the UV irradiation time was increased, the mean size of particles continuously decreased as a result of photoinduced Ag-NPs fragmentation. Based on X-ray diffraction (XRD), the UV-irradiated Ag-NPs were a face-centered cubic (fcc) single crystal without any impurity. This study reveals that the UV irradiation-mediated method is a green chemistry and promising route for the synthesis of stable Ag-NPs for several applications (e.g., medical and surgical devices). The important advantages of this method are that it is cheap, easy, and free of toxic materials.
The application of "green" chemistry rules to nanoscience and nanotechnology is very important in the preparation of various nanomaterials. In this work, we successfully developed an eco-friendly chemistry method for preparing silver nanoparticles (Ag-NPs) in natural polymeric media. The colloidal Ag-NPs were synthesized in an aqueous solution using silver nitrate, gelatin, and glucose as a silver precursor, stabilizer, and reducing agent, respectively. The properties of synthesized colloidal Ag-NPs were studied at different reaction times. The ultraviolet-visible (UV-vis) spectra were in excellent agreement with the obtained nanostructure studies performed by transmission electron microscopy (TEM) and their size distributions. The prepared samples were also characterized by X-ray diffraction (XRD) and atomic force microscopy (AFM). The use of eco-friendly reagents, such as gelatin and glucose, provides green and economic attributes to this work.
Silver nanoparticles were fabricated by ablation of a pure silver plate immersed in castor oil. A Nd:YAG-pulsed Q-switch laser with 1064-nm wavelength and 10-Hz frequency was used to ablate the plate for 10 minutes. The sample was characterized by ultraviolet-visible, atomic absorption, Fourier transform-infrared spectroscopies, and transmission electron microscopy. The results of the fabricated sample showed that the nanoparticles in castor oil were about 5-nm in diameter, well dispersed, and showed stability for a long period of time.
Silver nanoparticles (AgNPs) of a small size were successfully synthesized using the wet chemical reduction method into the lamellar space layer of montmorillonite/chitosan (MMT/Cts) as an organomodified mineral solid support in the absence of any heat treatment. AgNO3, MMT, Cts, and NaBH4 were used as the silver precursor, the solid support, the natural polymeric stabilizer, and the chemical reduction agent, respectively. MMT was suspended in aqueous AgNO3/Cts solution. The interlamellar space limits were changed (d-spacing = 1.24-1.54 nm); therefore, AgNPs formed on the interlayer and external surface of MMT/Cts with d-average = 6.28-9.84 nm diameter. Characterizations were done using different methods, ie, ultraviolet-visible spectroscopy, powder X-ray diffraction, transmission electron microscopy, scanning electron microscopy, energy dispersive X-ray fluorescence spectrometry, and Fourier transform infrared spectroscopy. Silver/montmorillonite/chitosan bionanocomposite (Ag/MMT/Cts BNC) systems were examined. The antibacterial activity of AgNPs in MMT/Cts was investigated against Gram-positive bacteria, ie, Staphylococcus aureus and methicillin-resistant S. aureus and Gram-negative bacteria, ie, Escherichia coli, E. coli O157:H7, and Pseudomonas aeruginosa by the disc diffusion method using Mueller Hinton agar at different sizes of AgNPs. All of the synthesized Ag/MMT/Cts BNCs were found to have high antibacterial activity. These results show that Ag/MMT/Cts BNCs can be useful in different biological research and biomedical applications, including surgical devices and drug delivery vehicles.
This paper presents the green synthesis of silver nanoparticles (Ag NPs) in aqueous medium. This method was performed by reducing AgNO(3) in different stirring times of reaction at a moderate temperature using green agents, chitosan (Cts) and polyethylene glycol (PEG). In this work, silver nitrate (AgNO(3)) was used as the silver precursor while Cts and PEG were used as the solid support and polymeric stabilizer. The properties of Ag/Cts/PEG nanocomposites (NCs) were studied under different stirring times of reaction. The developed Ag/Cts/PEG NCs were then characterized by the ultraviolet-visible (UV-Vis) spectroscopy, X-ray diffraction (XRD), transmission electron microscopy (TEM), scanning electron microscopy (SEM) and Fourier transform infrared (FTIR) spectroscopy.
Silver nanoparticles (Ag-NPs) have been successfully prepared with simple and "green" synthesis method by reducing Ag(+) ions in aqueous gelatin media with and in the absence of glucose as a reducing agent. In this study, gelatin was used for the first time as a reducing and stabilizing agent. The effect of temperature on particle size of Ag-NPs was also studied. It was found that with increasing temperature the size of nanoparticles is decreased. It was found that the particle size of Ag-NPs obtained in gelatin solutions is smaller than in gelatin-glucose solutions, which can be related to the rate of reduction reaction. X-ray diffraction, ultraviolet-visible spectra, transmission electron microscopy, and atomic force microscopy revealed the formation of monodispersed Ag-NPs with a narrow particle size distribution.
Silver nanoparticles (Ag NPs) were synthesized by the chemical reducing method in the external and interlamellar space of montmorillonite (MMT) as a solid support at room temperature. AgNO(3) and NaBH(4) were used as a silver precursor and reducing agent, respectively. The most favorable experimental conditions for synthesizing Ag NPs in the MMT are described in terms of the initial concentration of AgNO(3). The interlamellar space limits changed little (d-spacing = 1.24-1.47 nm); therefore, Ag NPs formed on the MMT suspension with d-average = 4.19-8.53 nm diameter. The Ag/MMT nanocomposites (NCs), formed from AgNO(3)/MMT suspension, were characterizations with different instruments, for example UV-visible, PXRD, TEM, SEM, EDXRF, FT-IR, and ICP-OES analyzer. The antibacterial activity of different sizes of Ag NPs in MMT were investigated against Gram-positive, ie, Staphylococcus aureus and methicillin-resistant S. aureus (MRSA) and Gram-negative bacteria, ie, Escherichia coli, Escherichia coli O157:H7, and Klebsiella pneumoniae, by the disk diffusion method using Mueller-Hinton agar (MHA). The smaller Ag NPs were found to have significantly higher antibacterial activity. These results showed that Ag NPs can be used as effective growth inhibitors in different biological systems, making them applicable to medical applications.
Using the chemical reduction method, silver nanoparticles (Ag NPs) were effectively synthesized into the zeolite framework in the absence of any heat treatment. Zeolite, silver nitrate, and sodium borohydride were used as an inorganic solid support, a silver precursor, and a chemical reduction agent, respectively. Silver ions were introduced into the porous zeolite lattice by an ion-exchange path. After the reduction process, Ag NPs formed in the zeolite framework, with a mean diameter of about 2.12-3.11 nm. The most favorable experimental condition for the synthesis of Ag/zeolite nanocomposites (NCs) is described in terms of the initial concentration of AgNO(3). The Ag/zeolite NCs were characterized by ultraviolet-visible spectroscopy, powder X-ray diffraction, transmission electron microscopy, scanning electron microscopy, energy dispersive X-ray fluorescence, and Fourier transform infrared. The results show that Ag NPs form a spherical shape with uniform homogeneity in the particle size. The antibacterial activity of Ag NPs in zeolites was investigated against Gram-negative bacteria (ie, Escherichia coli and Shigella dysentriae) and Gram-positive bacteria (ie, Staphylococcus aureus and methicillin-resistant Staphylococcus aureus) by disk diffusion method using Mueller-Hinton agar at different sizes of Ag NPs. All of the synthesized Ag/zeolite NCs were found to have antibacterial activity. These results show that Ag NPs in the zeolite framework can be useful in different biological research and biomedical applications.
Laser ablation of a silver plate immersed in virgin coconut oil was carried out for fabrication of silver nanoparticles. A Nd:YAG laser at wavelengths of 1064 nm was used for ablation of the plate at different times. The virgin coconut oil allowed formation of nanoparticles with well-dispersed, uniform particle diameters that were stable for a reasonable length of time. The particle sizes and volume fraction of nanoparticles inside the solutions obtained at 15, 30, 45 min ablation times were 4.84, 5.18, 6.33 nm and 1.0 × 10(-8), 1.6 × 10(-8), 2.4 × 10(-8), respectively. The presented method for preparation of silver nanoparticles in virgin coconut oil is environmentally friendly and may be considered a green method.
This study aims to determine the combined effects of hydrolysis time, temperature, pH and ratio of enzyme to substrate on the degree of hydrolysis (DH) of silver catfish frame using Response Surface Methodology. The proximate compositions of silver catfish frame and silver catfish hydrolysate powder were determined as well. The effects of independent factors were described using a three-level factors Face Centered Central Composite design. The suggested hydrolysis conditions for obtaining the optimum DH using Alcalase® were – temperature of 55oC, hydrolysis time of 163 min, pH of substrate at 9.45 and an enzyme concentration of 2.0%. The generated model showed a quadratic fit with experimental data. Proximate analyses revealed that silver catfish frame contained 25.02% protein, 68.21% fat and 7.08% ash. While silver catfish frame hydrolysate powder contained 65.05% protein, 32.92% fat and 0.86% ash. The protein recovery in silver catfish frame hydrolysate was as high as 71.6%.
In the present work, we prepared silver nanoparticles by laser ablation of pure silver plate in ethanol and then irradiated the silver nanoparticles using a 532 nm Q-switched Nd:YAG pulsed laser. Transmission electron microscopic images of the sample after irradiation clearly showed formation of big structures, such as microrods and microbelts in ethanol. The obtained microbelts had a width of about 0.166 μm and a length of 1.472 μm. The reason for the formation of such a big structure is the tendency of the nanoparticles to aggregate in ethanol before irradiation, which causes fusion of the nanoparticles.