Fabrication of electrospun polycaprolactone coated withchitosan-silver nanoparticles membranes for wound dressing applications

In this study, electrospun polycaprolactone membrane coated with chitosan-silver nanoparticles (CsAg), electrospun polycaprolactone/chitosan/Ag nanoparticles, was fabricated by immersing the plasma-treated electrospun polycaprolactone membrane in the CsAg gel. The plasma modification of electrospun polycaprolactone membrane prior to CsAg coating was tested by methylene blue stain and scanning electron microscope. The presence of silver and chitosan on the plasma-treated electrospun polycaprolactone membrane was confirmed by energy-dispersive X-ray spectroscopy and FT-IR spectrum. Scanning electron microscope observation was employed to observe the morphology of the membranes. The release of Ag ions from electrospun polycaprolactone/chitosan/Ag nanoparticles membrane was tested using atomic absorption spectrometry. Electrospun polycaprolactone/chitosan/Ag nanoparticles membrane inherited advantages from both CsAg gel and electrospun polycaprolactone membrane such as: increasing biocompatibility, mechanical strength, and antibacterial activity against both Gram-negative and Gram-positive bacteria. Thus, this investigation introduces a highly potential membrane that can increase the efficacy of the wound dressing process.     

Electrospun polyurethane and soy protein nanofibres for wound dressing applications

In this report, a novel wound dressing material has been woven by electrospinning technique and tested for its various properties. For the nanofibre mat, a mixture of polyurethane (PU) and soy protein isolate (SPI) was electrospun in conjugation with zinc oxide nanoparticles (ZnO Nps) and ciprofloxacin hydrochloride (CipHCl) to produce fibrous mats viz. PU/SPI/ZnO and PU/SPI/CipHCl. An optimum ratio (1 : 1) of PU/SPI was used as suitable polymeric ratio in order to produce homogenous nanofibres without beads having an average diameter in the range of 300–350 nm. The electrospun nanofibre‐based mats were characterised using X‐ray diffraction, Fourier transform infrared spectroscopy, ultraviolet‐visible spectroscopy, thermogravimetric analysis and scanning electron microscope. The mechanical properties of the nanofibrous mats were tested using universal testing machine. The wettability analysis was done using the contact angle measurement based on the sessile drop test. This study revealed that the electrospun PU/SPI‐based nanofibres are non‐sensitizing, non‐allergic and non‐toxic and that it can be used as a peculiar wound healing material.Inspec keywords: polymer fibres, nanofibres, nanomedicine, biomedical materials, wounds, electrospinning, zinc compounds, II‐VI semiconductors, wide band gap semiconductors, nanoparticles, nanofabrication, X‐ray diffraction, Fourier transform spectra, infrared spectra, ultraviolet spectra, visible spectra, thermal analysis, scanning electron microscopy, wetting, contact angle, toxicologyOther keywords: electrospun polyurethane nanofibres, soy protein nanofibres, wound dressing applications, electrospinning, nanofibre mat, soy protein isolate, zinc oxide nanoparticles, ciprofloxacin hydrochloride, X‐ray diffraction, Fourier transform infrared spectroscopy, ultraviolet‐visible spectroscopy, thermogravimetric analysis, scanning electron microscope, mechanical properties, universal testing machine, wettability, contact angle measurement, sessile drop test, nonsensitizing nanofibres, nonallergic nanofibres, nontoxic nanofibres, wound healing material, wavelength 300 nm to 350 nm, ZnO     

Electrospun polyvinylidene pyrolidone/gelatin membrane impregnated with silver sulfadiazine as wound dressing for burn treatment

Nanofibrous membranes used for burn treatment have become widely popular due to their large surface area and high porous structure. In this study, electrospinning was used to fabricate a blended nanofibrous membrane of polyvinylidene pyrolidone (PVP) and gelatin, to use as wound dressing. The physical and mechanical properties of this novel membrane were investigated using SEM, FTIR and tensile tests. Results showed that poor mechanical properties of gelatin, which are preferred in medical applications for curing burns as they allow for antigen activity and skin repair, can be enhanced by adding PVP in the solution. Silver sulfadiazine (AgSD), an antibacterial agent, was also impregnated into the PVP/gelatin nanofibrous structure during electrospinning. The membrane thus fabricated showed antibacterial activities against both the Gram-negative Escherichia coli and Gram-positive Staphylococcus aureus. AgSD release behaviour of fabricated samples indicated short-term drug delivery. It was concluded that the proposed drug-loaded membrane can be used as wound dressing, specifically, in treating skin burns.     

Morphological changes in biomimetically synthesized hydroxyapatite and silver nanoparticles for medical applications

A precise control of morphology, which plays a significant role towards the application of materials, can be achieved by studying the effects of macromolecules as nucleation templates for minerals in a biomineralization process. The present investigation aims to understand such effects on medically important materials. Thus, Silver (Ag) and Calcium hydroxyapatite [Ca₁₀(PO₄)₆(OH)₂] were synthesized in both biopolymer (gelatin) and synthetic polymer (PVA) media, with aqueous medium as the control to portray a collage of how the interface between the macromolecule and the mineral controls the final morphology of the materials. It was also observed that the change of morphology of the products does influence their performances in specific applications like antibacterial property of the nanoparticles of silver was found to the best when synthesized in aqueous media. Thus, we consider that the organic–inorganic interaction to be of vital significance in the synthesis of complex shapes and sizes of nanoparticles for important applications. This article is dedicated to Professor T. R. Anantharaman a great teacher and founder of the school of research at the Department of Metallurgical Engineering, Banaras Hindu University (BHU). Interaction with this eminent visionary has greatly influenced our scientific and spiritual thinking.     

Manifestation of the silver nanoparticles incorporated into the poly vinyl alcohol matrices

Electrical and optical properties of the silver nanoparticles (Ag NPs) incorporated into the polyvinyl alcohol (PVA) matrices were investigated as a function of Ag NPs. The intensities of FT-Raman bands have a maximum corresponding to the Ag NP amount about 3.6 mg.. The PVA doped with different amounts of Ag NPs shows UV-Visible peaks, were red shifted by Ag NPs increase, while their intensities according well with the FT-Raman spectra. The UV-Visible spectra for the 3.6 mg Ag NPs doped in PVA presented a small red shift and band intensity decrease by increasing temperature.     

Electrospun polyvinyl alcohol/chitosan composite nanofibers involving Au nanoparticles and their in vitro release properties

Au nanoparticles (Au NPs) containing polyvinyl alcohol (PVA)/chitosan (CS) composite nanofibers were successfully prepared by a simple and effective method called electrospinning. Au NPs were firstly synthesized under a mild condition with CS as the reducing agent and stabilizer, followed by being mixed with PVA solution and then the resulting fibers were fabricated. The research indicated that Au NPs were indeed doped into the as-prepared fibers and the composite fibers well preserved Au NPs' unique optical characteristics. Additionally, with the adjustment of the weight ratios between PVA and CS, the diameter distribution and the morphology of the nanofibers were largely changed. In vitro drug release experiments demonstrated that the drug release rate can be conveniently controlled by changing the crosslink time.     

Novel alginate based nanocomposite hydrogels with incorporated silver nanoparticles

Alginate colloid solution containing electrochemically synthesized silver nanoparticles (AgNPs) was investigated regarding the nanoparticle stabilization and possibilities for production of alginate based nanocomposite hydrogels in different forms. AgNPs were shown to continue to grow in alginate solutions for additional 3 days after the synthesis by aggregative mechanism and Ostwald ripening. Thereafter, the colloid solution remains stable for 30 days and could be used alone or in mixtures with aqueous solutions of poly(vinyl alcohol) (PVA) and poly(N-vinyl-2-pyrrolidone) (PVP) while preserving AgNPs as verified by UV–Vis spectroscopy studies. We have optimized techniques for production of Ag/alginate microbeads and Ag/alginate/PVA beads, which were shown to efficiently release AgNPs decreasing the Escherichia coli concentration in suspensions for 99.9% over 24 h. Furthermore, Ag/hydrogel discs based on alginate, PVA and PVP were produced by freezing-thawing technique allowing adjustments of hydrogel composition and mechanical properties as demonstrated in compression studies performed in a biomimetic bioreactor.     

Fatty acid-based polyurethane films for wound dressing applications

Fatty acid-based polyurethane films were prepared for use as potential wound dressing material. The polymerization reaction was carried out with or without catalyst. Polymer films were prepared by casting-evaporation technique with or without crosslink-catalyst. The film prepared from uncatalyzed reaction product with crosslink-catalyst gave slightly higher crosslink density. The mechanical tests showed that, the increase in the tensile strength and decrease in the elongation at break is due to the increase in the degree of crosslinking. All films were flexible, and resisted to acid solution. The films prepared without crosslink-catalyst were more hydrophilic, absorbed more water. The highest permeability values were generally obtained for the films prepared without crosslink catalyst. Both the direct contact method and the MMT test were applied for determination of cytotoxicity of polymer films and the polyurethane film prepared from uncatalyzed reaction product without crosslink-catalyst showed better biocompatibility property, closest to the commercial product, Opsite.     

Zephyranthes candida flower extract mediated green synthesis of silver nanoparticles for biological applications

The development of biologically active nanoparticles (NPs) has played a prominent role in medicinal, pharmaceuticals and bio-nanotechnology fields. Phytosynthesis is a simple, reproducible, and effective method to produce highly stable metal nanoparticles. In this present work, silver (Ag) nano particles (NPs) were produced using Zephyranthes candida (Z. candida) flower extract as a sustainable, cost-effective, and non-hazardous stabilizing agent. In the view of X-ray diffraction (XRD) analysis, the face centred cubic structure of Ag NPs was revealed. From the UV–Vis spectral analysis, the formations of Ag NPs were further confirmed through surface plasmon resonance (SPR) at the highest absorbance (λ_max) of 418 nm. FT-IR represents the spectra that reveal the presence of diverse functional groups along with their vibrational modes present in Ag NPs and Z.candida flower extract. SEM and TEM denote the formation of spherical morphology of Ag NPs. Furthermore, EDX and XPS spectra confirmed the purity of the prepared Ag NPs. Finally, the biological studies such as anti-inflammatory, anti-diabetic, anti-oxidant, anticancer confirm the bioactivity of the synthesized Zephyranthes Candida mediated Ag NPs.     

Electrospun fibers for tissue engineering, drug delivery, and wound dressing

Electrospinning, a technique well known for fabricating nanoscale fibers, has recently been studied extensively due to its various advantages such as high surface-to-volume ratio, tunable porosity, and ease of surface functionalization. The resulting fibers are extremely useful for applications in the fields of tissue engineering, drug delivery, and wound dressing. Since electrospun fiber mimic extracellular matrix of tissue in terms of scale and morphology, its potential to be used as scaffold is continuously explored by researchers, especially in the field of vascular, nerve, bone, and tendon/ligament tissue engineering. Besides morphology, physical, and chemical properties, electrospun scaffolds are often evaluated through various cell studies. Researchers have adopted approaches such as surface modification and drug loading to enhance the property and function of scaffold. This review gives an overview of some current aspects of various applications of electrospun fibers, particularly in biomedical fields, how researchers have enhanced electrospun fibers with different methods and attempted to overcome the inherent limitation of electrospinning by using novel techniques.     

Properties of hydrogels synthesized by freezing and thawing aqueous polyvinyl alcohol solutions and their applications

The hydrogel synthesized by freezing a polyvinyl alcohol (PVA) aqueous solution and thawing it slowly has high water content, excellent mechanical properties of high tensile strength, elongation and good shape recovery by elasticity. The PVA used had a degree of polymerization of 2500 and a degree of saponification of 99.5 mol%. The solution was obtained by dissolving 7.5 g of PVA in 80 g of water, this was frozen at –50°C for 3 h and then warmed up to room temperature over 10h. This freezing–thawing process was repeated once again and a hydrogel was synthesized. The hydrogel had a water content of about 90 wt%. Its tensile strength was 0.6 MPa and the elongation at break was 130%. The shape of the hydrogel which was deformed by an external force recovered in a short time when it was released from the force. This recovery had good persistence and repeatability. Applying these properties a strain sensor and a gas pressure sensor were tested. Furthermore, a PVA hydrogel rod containing polyacrylic acid was used as a bending actuator. This hydrogel had the ability to deform when direct current was applied.     

Hyaluronic acid and silver sulfadiazine-impregnated polyurethane foams for wound dressing application

Five different kinds of PU foam wound dressings were prepared to investigate their wound healing capability. They include (i) PU+silver sulfadiazine (AgSD), (ii) PU+alginate (Al), (iii) PU+Al+AgSD, (iv) PU+hyaluronic acid (HA), and (v) PU+HA+AgSD. Physical properties and in vitro behaviors of AgSD release and fibroblast adhesion on those dressings were evaluated. From the drug release and fibroblast adhesion studies, it was observed that PU foam impregnated with both HA and AgSD shows good drug release behavior and low adhesion of the cells. Furthermore, the HA and AgSD-containing PU foam showed excellent wound healing effect without any inflammation or yellow cluster. The wound size decreased around 77% after 1 week application of that foam dressing onto a rat skin defect.     

纳米银/聚乙烯醇复合物的生物合成及其对6种水产病原菌的抑菌活性

纳米银作为一种新型抑菌剂有望成为传统抑菌剂的替代品,制备稳定、高效、环保的新型纳米银抑菌产品成为当今的研究热点。本研究以葡萄籽提取液为还原剂和稳定剂,聚乙烯醇(PVA)为载体,采用一步法“绿色”生物合成出一种纳米银/聚乙烯醇复合物(AgNPs/PVA)。通过紫外-可见(UV-Vis)吸收光谱、透射电镜(TEM)、X射线衍射(XRD)等手段对合成产物进行了表征。结果表明银离子被葡萄籽提取物成功还原成纳米银并附着在PVA的表面,纳米银颗粒均匀,呈现单分散状态,粒径较小,平均粒径为14 nm左右。AgNPs/PVA对鳗弧菌、溶藻弧菌、副溶血弧菌、哈维氏弧菌、灿烂弧菌及点状气单胞菌等6种典型的水产病原菌均有显著的抑菌效果。以溶藻弧菌为指示菌,AgNPs/PVA的最小抑菌浓度(MIC)为1.1 μg/mL,最小杀菌浓度(MBC)为2.2 μg/mL。AgNPs/PVA的Zeta电位为?24.1 mV,表明纳米银颗粒间有很强的排斥力,为其稳定分散提供保障,后续实验证明制备的AgNPs/PVA具有良好的稳定性和热稳定性。以上研究结果表明,AgNPs/PVA复合材料在水产养殖病害防治中具有广阔的应用前景。      

Medicinal plants mediated the green synthesis of silver nanoparticles and their biomedical applications

The alarming effect of antibiotic resistance prompted the search for alternative medicine to resolve the microbial resistance conflict. Over the last two decades, scientists have become increasingly interested in metallic nanoparticles to discover their new dimensions. Green nano synthesis is a rapidly expanding field of interest in nanotechnology due to its feasibility, low toxicity, eco‐friendly nature, and long‐term viability. Some plants have long been used in medicine because they contain a variety of bioactive compounds. Silver has long been known for its antibacterial properties. Silver nanoparticles have taken a special place among other metal nanoparticles. Silver nanotechnology has a big impact on medical applications like bio‐coating, novel antimicrobial agents, and drug delivery systems. This review aims to provide a comprehensive understanding of the pharmaceutical qualities of medicinal plants, as well as a convenient guideline for plant‐based silver nanoparticles and their antimicrobial activity.     

Synthesis and characterization of nanofiber webs of chitosan/poly(vinyl alcohol) blends incorporated with silver nanoparticles

Nanofiber webs of chitosan (CS)/poly(vinyl alcohol) (PVA) blends incorporated with silver nanoparticles (AgNs) were fabricated by two different methods: a refluxing method and an annealing method. We found that the characterization and antibacterial activity of AgNs depended on not only the fabrication methods but also the weight ratio of CS and PVA in the CS/PVA blend. The change in the size and number of AgNs due to the interaction between AgNs and CS, in turn, affected the antibacterial property of the non-woven webs. Non-woven webs of CS/PVA nanofibers containing AgNs that were fabricated by the refluxing method showed higher antibacterial ability against Escherichia coli than did the other types of non-woven webs. The morphology of the electrospun non-woven webs was observed by field emission scanning electron microscopy. The characterization of AgN formation on the surface of electrospun fibers was examined by transmission electron microscopy, attenuated total reflectance-Fourier transform infrared spectroscopy, and X-ray photoelectron spectroscopy.     

Synthesis of silver nanoparticles from a Desmodium adscendens extract and its antibacterial evaluation on wound dressing material

The one‐pot synthesis of silver nanoparticles (AgNPs) using the medium‐polar extract of Desmodium adscendens (Sw.) DC. is presented here as an alternative synthesis of metal NPs. Characterisation of the formed NPs showed polydispersed AgNPs ranging from 15 to 100 nm where the concentration of metal ions was found to play a role in the size and shape of the prepared NPs. It could be established that the flavonoids, saponins, and alkaloids present in the extract acted as both reducing and stabilising agents during the formation of the capped metal NPs. This means of NP synthesis was also employed during the in situ immobilisation of AgNPs on gauze and plaster. An evaluation of the antibacterial activity of the medium‐polar D. adscendens extract, AgNPs suspended in solution, and the immobilised AgNPs against Staphylococcus aureus (ATCC 25923), Bacillus cereus (ATCC 11778), and Escherichia coli (ATCC 25922) showed high efficacy against the latter in particular. This suggests that gauze, dilute silver nitrate solutions, and D. adscendens extract could be used successfully in the simple in situ preparation of effective antibacterial wound dressings.Inspec keywords: wounds, silver, nanoparticles, nanomedicine, biomedical materials, antibacterial activityOther keywords: size 15 nm to 100 nm, antibacterial wound dressings, in situ preparation, dilute silver nitrate solutions, alkaloids, saponins, flavonoids, metal ions, wound dressing material, antibacterial evaluation, Desmodium adscendens extract, silver nanoparticle synthesis     

Optical properties of the synthesized ZnO with ion implanted silver nanoparticles

Technical Physics Letters - The implantation results of a thin ZnO film formed by vacuum magnetron sputtering when irradiated by Ag+ ions with an energy of 30 keV, radiation dose of 1.5 × 1017...     

Eco-friendly green synthesis of silver nanoparticles and their potential applications as antioxidant and anticancer agents

Abstract

Eco-friendly green synthesis of nanoparticles using medicinal plants gained immense importance due to its potential therapeutic uses. In the current study, silver nanoparticles (AgNPs) were synthesized using water extract of Jurinea dolomiaea leaf and root at room temperature. MTT assay was used to study anticancer potential of AgNPs against cervical cancer cell line (HeLa), breast cancer cell lines (MCF-7), and mouse embryonic fibroblast (NIH-3 T3) cell line for toxicity evaluation. The antioxidant potential was evaluated using stable DPPH radicals. In addition, the apoptotic nuclear changes prompted by AgNPs in more susceptible HeLa cells were observed using fluorescence microscope through DAPI and PI staining. Physiochemical properties of biosynthesized AgNPs were characterized using various techniques. AgNPs were formed in very short time and UV–vis spectra showed characteristic absorption peak of AgNPs. SEM and TEM showed spherical shape of AgNPs and XRD revealed their crystalline nature. EDX analysis revealed high percentage of silver in green synthesized AgNPs. FTIR analysis indicated involvement of secondary metabolites in fabrication of AgNPs. In vitro cytotoxic and antioxidant study revealed that herb and biosynthesized AgNPs exhibited significant dose-dependent and time-dependent anticancer and antioxidant potential. Furthermore, study on normal cell line and microscopic analysis of apoptosis revealed that AgNPs exhibited good safety profile as compared to cisplatin and induces significant apoptosis effect. Based on the current findings, it is strongly believe that use of J. dolomiaea offers large scale production of biocompatible AgNPs that can be used as alternative anticancer agents against cancer cell lines tested.     

Development of novel chitin/nanosilver composite scaffolds for wound dressing applications

Antibiotic resistance of microorganisms is one of the major problems faced in the field of wound care and management resulting in complications like infection and delayed wound healing. Currently a lot of research is focused on developing newer antimicrobials to treat wounds infected with antibiotic resistant microorganisms. Silver has been used as an antimicrobial agent for a long time in the form of metallic silver and silver sulfadiazine ointments. Recently silver nanoparticles have come up as a potent antimicrobial agent and are finding diverse medical applications ranging from silver based dressings to silver coated medical devices. Chitin is a natural biopolymer with properties like biocompatibility and biodegradability. It is widely used as a scaffold for tissue engineering applications. In this work, we developed and characterized novel chitin/nanosilver composite scaffolds for wound healing applications. The antibacterial, blood clotting and cytotoxicity of the prepared composite scaffolds were also studied. These chitin/nanosilver composite scaffolds were found to be bactericidal against S. aureus and E. coli and good blood clotting ability. These results suggested that these chitin/nanosilver composite scaffolds could be used for wound healing applications.