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Background: The skin is one of the most essential organs of the body that plays a vital role. Protecting the skin from damage is a critical challenge. Therefore, the ideal wound dressing that has antibacterial, mechanical, biodegradable, and non-toxic properties can protect the skin against injury and accelerate and heal the wound., Objective: In this study, a nano-wound dressing is designed for the first time. This work is aimed to optimize and act as a dressing to speed up the wound healing process., Methods: Graphene Oxide (GO) was produced by the hummer method. In the next step, GO-copper (Cu) nanohybrid was prepared, then GO-Cu -Curcumin (Cur) nanohybrid was synthesized. Using the electrospinning method, polyvinyl alcohol (PVA)/GO-Cu -Cur were spun, and finally, related analyses were performed to investigate the properties and synthesized chemicals., Results: The results showed that the nanocomposite was synthesized correctly, and the diameter of the nanofibers was 328 nm. The use of PVA improved the mechanical properties. In addition, the wound dressing had biodegradable, antimicrobial, and non-toxic properties. The results of the scratch test and animal model showed that this nanocomposite accelerated wound healing and after 14 days showed 92.25% wound healing., Conclusion: The synthesized nanocomposite has the individual properties and characteristics of an ideal wound dressing and replaces traditional methods for wound healing., (Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.net.)

Glioblastoma multiforme (GBM) is considered to be one of the most serious version of primary malignant tumors. Temozolomide (TMZ), an anti-cancer drug, is the most common chemotherapeutic agent used for patients suffering from GBM. However, due to its inherent instability, short biological half-life, and dose-limiting characteristics, alternatives to TMZ have been sought. In this study, the TMZ-loaded PLGA nanoparticles were prepared by employing the emulsion solvent evaporation technique. The prepared TMZ-PLGA-NPs were characterized using FT-IR, zeta potential analyses, XRD pattern, particle size estimation, TEM, and FE-SEM observations. The virotherapy, being safe, selective, and effective in combating cancer, was employed, and TMZ-PLGA-NPs and oncolytic Newcastle Disease Virus (NDV) were co-administered for the purpose. An AMHA1-attenuated strain of NDV was propagated in chicken embryos, and the virus was titrated in Vero-slammed cells to determine the infective dose. The in vitro cytotoxic effects of the TMZ, NDV, and the TMZ-PLGA-NPs against the human glioblastoma cancer cell line, AMGM5, and the normal cell line of rat embryo fibroblasts (REFs) were evaluated. The synergistic effects of the nano-formulation and viral strain combined therapy was observed on the cell lines in MTT viability assays, together with the Chou-Talalay tests. The outcomes of the in vitro investigation revealed that the drug combinations of NDV and TMZ, as well as NDV and TMZ-PLGA-NPs exerted the synergistic enhancements of the antitumor activity on the AMGM5 cell lines. The effectiveness of both the mono, and combined treatments on the capability of AMGM5 cells to form colonies were also examined with crystal violet dyeing tests. The morphological features, and apoptotic reactions of the treated cells were investigated by utilizing the phase-contrast inverted microscopic examinations, and acridine orange/propidium iodide double-staining tests. Based on the current findings, the potential for the use of TMZ and NDV as part of a combination treatment of GBM is significant, and may work for patients suffering from GBM.

The need for an ideal tissue construct has lead to the search of a myriad of polymer composites with desirable properties. The nature, location and type of tissue to be regenerated determines the type of material to be used. A bone construct has its own requirements such as osteoconductivity, mineralization tendency, synchronized degradation rate, osteogenic differentiation potential etc, which results in search of new possible combination of materials aimed to improve tissue response. The present study involves fabrication of Chitosan/Polyvinyl alcohol (PVA)/β-Tricalcium Phosphate (β-TCP)/Cellulose nanocrystals (CNC) porous composite by freeze drying process to be used as bone tissue engineering matrix. CNCs were isolated by acid hydrolysis of cellulose derived from pistachio shells. The prepared scaffold samples were characterized by Fourier-transform infrared spectroscopy (FTIR), Thermogravimetric analysis (TGA), Atomic Force Microscopy (AFM), Scanning Electron Microscopy (SEM) and X-RAY Diffraction analysis (XRD). The scaffolds exhibited refinement in pore morphology and increased mineralization tendency on increasing CNC concentration. Samples with 1% and 5% CNC concentration have deposited apatite crystals with Ca/P ratio of 1.61 and 1.66 which is very close to the stoichiometric ratio of natural bone apatite. Compressive modulus of CS/PVA/β-TCP/CNC composite increased on increasing the CNC concentration to 5%. The highest cell viability was recorded in scaffolds with 5% CNC content. Though cell attachment tendency was observed in all samples but the samples with 5 and 10% CNC content demonstrated higher cell densities with significant calcium depositions when cultured for 72 h. Samples with 5% CNC concentration also possessed highest cell differentiation capabilities.

Nickel oxide (NiO) nanoparticles (NPs) and graphene quantum dots (GQDs) reinforced polyvinyl alcohol (PVA) nanocomposite films were prepared using a solution casting technique. The physicochemical characteristics of PVA/NiO/GQDs (PNG) nanocomposite films were studied using Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), thermogravimetric analysis (TGA), and field emission scanning electron microscopy (FESEM). The obtained PNG nanocomposite films showed good mechanical flexibility and improved tensile strength. The influence of nanofiller concentrations on PNG nanocomposite film. The obtained results demonstrate an increase in the activation energy (Ea) up to PNG3 upon increasing the GQDs concentration and thereafter, its decreases. The fundamental interactions of the constituents of PNG nanocomposite film were investigated using density functional theory (DFT). This study on electronic structure reveals that the PVA model indirectly interacts with GQDs through the NiO model. This configuration is favoured in terms of interaction energy (-78 kJ/mol) compared to the one in which PVA interacts directly with the GQDs model., (Copyright © 2021 Elsevier Inc. All rights reserved.)

This study aimed to develop and optimise a Curcumin-loaded SLNs (C-SLNs) patch through a new approach for transdermal delivery. C-SLNs were optimised through the response surface central composite design using the modified injection method. Optimised C-SLNs were loaded into a polyvinyl alcohol-based patch through the backing membrane method. Compatibility studies (FTIR, XRPD) , in vitro release, ex vivo skin permeation, accelerated stability, and evaluation studies of the patch were also performed. Prepared C-SLNs exhibited average particle diameter of 170   ± 2 nm with an encapsulation efficiency of 90 ± 3.5% (w/w) while SEM illustrated spherical shape of particles. In vitro release data ensured a sustained release for up to 72 hours. The enhancement ratio of C-SLNs based patch with permeation enhancer (PE) was high up to 6.5 folds as compared to patch without PE. It is concluded that the modified injection method is simple, economical, and less time consuming for the development of C-SLNs patch for the transdermal route.

The electrospinning of polymers has previously shown excellent potential for localised gene therapy. Thus, it was proposed that for the first time, the cell-penetrating CHAT peptide could be utilised to deliver DNA via electrospun nanofibres for localised gene therapy treatment. CHAT is an effective delivery system that encapsulates pDNA to form nanoparticles with the physicochemical characteristics for cellular uptake and protein generation. In this study, the production of smooth, bead-free PVA nanofibres by electrospinning was optimised through a Design of Experiments approach. Bead-free PVA nanofibres were consistently produced using the optimised parameters as follows: applied voltage (8 kV); collector-emitter distance (8 cm); polymer flow rate (4 µL/min); polymer concentration (9 wt% polymer); PVA M W (146-180 kDa). PVA nanofibres were subsequently crosslinked in 1 vol% glutaraldehyde in methanol to confer stability under aqueous conditions with minimal change to morphology, and no compromise to biocompatibility. Nanoparticles of CHAT/pDNA were synthesised and incorporated into the crosslinked nanofibres via soak-loading. Evaluation studies indicated that 100% of the loaded cargo was released within 48 h from the nanofibres. Furthermore, the released pDNA retained structural integrity and functionality as confirmed by gel electrophoresis and transfection studies in NCTC-929 fibroblast cells. Taken together, this data demonstrates that delivery of CHAT/pDNA nanoparticles from electrospun PVA nanofibres represents a solution for localised gene therapy., (Copyright © 2021 Elsevier B.V. All rights reserved.)

Background: Due to the noninvasive nature of boron neutron capture therapy (BNCT), it is considered a promising cancer treatment method. Aim: To investigate whether polyvinyl alcohol/boric acid crosslinked nanoparticles (PVA/BA NPs) are an efficient delivery system for BNCT. Materials & methods: PVA/BA NPs were synthesized and cocultured with brain and oral cancers cells for BNCT. Results: PVA/BA NPs had a boron-loading capacity of 7.83 ± 1.75 w/w%. They accumulated in brain and oral cancers cells at least threefold more than in fibroblasts and macrophages. The IC 50  values of the brain and oral cancers cells were at least ninefold and sixfold lower than those of fibroblasts and macrophages, respectively. Conclusion: Theoretically, PVA/BA NPs target brain and oral cancers cells and could offer improved therapeutic outcomes of BNCT.

An active film was prepared by corn starch (CS), polyvinyl alcohol (PVA) and carvacrol nanoemulsions (CNE). The microstructure and properties of CNE/corn starch/PVA (CNE/CSP) films were characterized and investigated. Scanning electron microscopy (SEM) revealed the uniform distribution of CNE and discontinuity of the film matrix. Fourier transform infrared (FT-IR) and rheological analysis indicated that CNE could weaken molecular interaction of the film matrix. X-ray diffraction (XRD) show that the films are amorphous and CNE has no effect on crystal structure of the films. Incorporation of CNE significantly increased the tensile strength, Young's modulus, elongation at break, barrier (water vapor and ultraviolet), antioxidant and antifungal activity. With the CNE incorporated, the optimal tensile strength, Young's modulus, elongation at break and antioxidant activity of the films can reach 12 MPa, 11 MPa, 133%, 81%, respectively. Minimum water vapor permeability was 3.1 × 10 -12 gd -1 m -1 Pa -1 . Notably, films incorporated with CNE (≥20%) had good DPPH free radical scavenging ability (>50%) when stored up to 6 days. Films with 25% CNE exhibited excellent antifungal activity against Trichoderma sp. and its inhibitory zone was 47 mm. Overall, the CSP films loaded with CNE (>15%) could be used as food packing materials with good antioxidant and antimicrobial activities., (Copyright © 2020 Elsevier B.V. All rights reserved.)

In the present work, novel berberine nano-colloids hydrogel (BNH) was prepared for improving wound healing of diabetic rats. Polyvinyl alcohol (PVA), sodium alginate (Alg) were adopted as building blocks to form BNH. Calcium ions was used as crosslink agent to construct BNH. The skin injury model of diabetic rats was successfully established, and the prepared hydrogel was applied to the wound. Animal experiments proved that BNH could promote wound healing of diabetic rats. Further molecular mechanism research revealed that BNH could inhibit the expression of NF-κB, TNF-a and IL-6, but increase the expression of F VEGF, CD 31 and SMA by activating Sirt 1 which were benefit for wound healing of diabetic rats., (Copyright © 2019 Elsevier B.V. All rights reserved.)

Nowadays many drugs with improved therapeutic efficacy are discovered but cannot be utilized due to their low solubility and insufficient bioavailability. An example of such a drug molecule is a protein kinase C inhibitor that influences an enzyme which plays an important role in several signal transduction cascades. The aim of this study was to formulate a stable nanoparticle dispersion of the PKC inhibitor encapsulated into PLGA nanoparticles (NPs). Encapsulation of the PKC inhibitor into PLGA NPs of 100-200 nm diameter should provide a targeted delivery to the inflammation sites. The NPs were prepared via nanoprecipitation and different surfactants were investigated: Fully and partially hydrolyzed poly(vinyl alcohol) (PVA, Mowiol X-88 and X-98), poloxamers (Pluronic F68 and F127) and polysorbates (Tween 20 and 80). From all surfactants tested, only NPs prepared with partially hydrolyzed PVA (Mowiol X-88) provided the desired stability throughout the downstream processes. These NPs were subsequently analyzed regarding their particle size, polydispersity, encapsulation efficiency and loading capacity. Dynamic light scattering results revealed that monodisperse NPs of 150-220 nm were formed, a size range that favors targeted delivery. The drug encapsulation efficiency varied from 31 to 75% with a drug loading of 1.3-2%. Moreover, the long-term stability was studied and the residual amount of PVA of the NP solutions was quantified via nuclear magnetic resonance (NMR) measurements. The shell-less hen's egg model was used to test toxic effects (hemorrhage, vascular lysis, thrombosis, hemolysis and lethality) of the NPs in a more complex biological system under dynamic flow conditions., (Copyright © 2019 Elsevier B.V. All rights reserved.)

Silver/polymer nanocomposites have made inroads into the fields of electronic devices, thermally conductive materials, antimicrobial agents and sensors. Here, we present the hydrothermal synthesis of a novel three-dimensional self-standing silver/crosslinked-poly(vinyl alcohol) (Ag/crosslinked-PVA) hybrid network constructed by linking three different subunits, namely, microfibers, nanowires and nanoparticles. One-dimensional crosslinked-PVA-based microfibers act as the skeleton of the sponge. Ag nanoparticles are uniformly embedded in the interior of the microfibers, and Ag nanowires grow outward from the interior of the microfibers. This Ag/crosslinked-PVA multi-architecture has not be observed or reported in current state-of-the-art studies. We simultaneously carry out two types of reactions, chemical reduction of Ag + ions and intermolecular crosslinking of PVA chains, in the synthesis under hydrothermal conditions. Ag nanoparticles are formed and dispersed in the crosslinked-PVA microspheres. Then, these Ag/crosslinked-PVA microspheres bridge each other, forming microchains and microfibers. Ultimately, linear aggregation, which has rarely been mentioned in the literature, occurs in some adjacent Ag nanoparticles in the microfibers, and the Ag nanoparticles reorganize into nanowires. The Ag/crosslinked-PVA network is shown to be converted into a Ag/C composite through annealing, which exhibits electrocatalytic activity for glucose oxidation and can be used as a self-supporting electrode in an antibacterial nonenzymatic glucose sensor., (Copyright © 2018 Elsevier Inc. All rights reserved.)

The intradermal delivery of biologics has long been recognized as attractive approach for cutaneous immunotherapy, particularly vaccination. Although intradermal (i.d.) or subcutaneous (s.c.) injection provide reproducible dosing and good cost- and delivery efficiency, the major objective to avoid sharps and the need for enhanced storage stability have renewed the interest in alternative needle-free delivery strategies. This study presents a new concept for the delivery of macromolecules and nanoparticles to viable skin layers with a high density of professional antigen-presenting cells (APCs). Stable polyvinyl alcohol (PVA) polymer films as well as PVA blends with carboxymethyl cellulose (CMC) or cross-linked carbomer were prepared using an easily-scalable film casting technique. Fluorescein isothiocyanate (FITC) and rhodamine B-labeled dextrane 70 kDa (RD70), used as small and macromolecular model substances, or polystyrene (PS)-nano- and microparticles with diameters of 0.5 µm and 5 µm were directly incorporated into the polymer formulations at varying concentrations. The assembly of the polymer films with an occlusive backing tape created a film patch that provided a fast drug release upon dissolution of the water-soluble film and facilitated an intradermal drug delivery on laser microporated skin. The minimally-invasive P.L.E.A.S.E.® laser poration system (Pantec Biosolutions, Ruggell, Liechtenstein) provided access to viable skin layers by thermally ablating the superficial tissue with a pulsed Er:YAG laser (λ = 2.94 µm). In our in vitro study using excised pig skin, laser microporation induced a 4- to 5-fold increase of water transport (TEWL) through excised skin in a Franz diffusion cell compared to intact skin. The TEWL values detected were comparable to in vivo human skin. The increased water transport facilitated the dissolution of all topically applied dry PVA-based film formulations within 6 h. No dissolution of the films was seen on intact skin. The incubation of the film patches on laser microporated skin for 24 h led to a considerable intradermal delivery of RD70 or PS-nanoparticles, which was superior for pure PVA films compared to PVA-CMC or PVA-carbomer blend formulations. No intradermal delivery was observed on intact skin or when larger PS-microparticles with a diameter of 5 µm were investigated. The presented concept provides a unique opportunity to exploit the improved storage stability of sensitive drug molecules in dry film formulations while providing protection and functionality., (Copyright © 2018 Elsevier B.V. All rights reserved.)

The aim of this study was to prepare a visually responsive intelligent film based on poly (vinyl alcohol) (PVA), chitosan nanoparticles (CHNPs) and mulberry extracts (MBE). CHNPs were first prepared by using ionotropic gelation method to enhance the mechanical properties of PVA based films. The morphology, particle size, zeta potential and crystallinity of CHNPs were measured. The resultant CHNPs were spherical with a diameter of 381.2nm, with high stability and a zeta potential of 49.1±1.33mV. The film with 6% CHNPs (P-C6) had the highest tensile strength (∼73.43MPa). MBE was incorporated into the P-C6 film. The film containing 20% MBE had the highest tensile strength and showed visible color responses to variations across pH 1-13. The film was tested by monitoring the spoilage of fish. The color of the film changed from red to green as the fish spoiled. Therefore, the pH responsive intelligent film developed here can be used as a package label to detect food spoilage., (Copyright © 2017 Elsevier B.V. All rights reserved.)

Gefitinib is an anticancer agent which acts by inhibiting epidermal growth factor receptor tyrosine kinase receptors. The aim of the present study was to prepare gefitinib nanosuspension. Gefitinib was encapsulated in Eudragit ® RL100 and then dispersed in stabilizer solution, polyvinyl alcohol, and polyvinylpyrrolidone K30. Nanosuspension was prepared by using homogenization and ultrasonication techniques. The quality by design approach was also used in the study to understand the effect of critical material attributes (CMAs) and critical processing parameters (CPPs) on critical quality attributes and to improve the quality and safety of formulation. To study the effect of CMAs and CPPs, 2 3 full factorial design was applied. The particle size, polydispersity index, and zeta potential of the optimized solution were 248.20 nm, 0.391, and -5.62 mV, respectively. Drug content of the optimized nanoformulation was found to be 87.74%±1.19%. Atomic force microscopy studies of the optimized formulation confirmed that the prepared nanoparticles are smooth and spherical in nature. In vitro cytotoxicity studies of the nanosuspension on Vero cell line revealed that the formulation is nontoxic. The gefitinib nanosuspension released 60.03%±4.09% drug over a period of 84 h, whereas standard drug dispersion released only 10.39%±3.37% drug in the same duration. From the pharmacokinetic studies, half-life, C max , and T max of the drug of an optimized nanosuspension were found to be 8.65±1.99 h, 46,211.04±5,805.97 ng/mL, and 6.67±1.77 h, respectively. A 1.812-fold increase in relative bioavailability of nanosuspension was found, which confirmed that the present formulation is suitable to enhance the oral bioavailability of gefitinib., Competing Interests: The authors report no conflicts of interest in this work.

Nucleic acid-based therapeutics offer enormous potential in the treatment of various pathologies. For DNA or RNA delivery, nanoparticle systems based on lipids or polymers have been developed. However, colloidal instability in solution, poor storage properties especially as dry powder and little stability against an aggressive environment, e.g. after oral application, are major issues. Furthermore, there is an urgent need for sustained release systems that allow for fine-tuned, long-term temporal and spatial nanoparticle release. In this paper, we describe the embedding of polymeric nanoparticles for gene delivery, namely polyethylenimine (PEI)-based polyplexes and their corresponding liposome-modified analogues (lipopolyplexes), into microparticulate poly (vinyl alcohol) (PVA) hydrogels. Various parameters are modified, and major differences are found. PVA is explored with two different molecular weights and at different concentrations, furthermore different emulsifiers and acetone for extraction are employed, and the protocol is performed with or without repetitive freeze/thaw cycles for physical PVA crosslinking. We thereby establish Nanoparticles-in-Microparticle Delivery Systems (NiMDS) that are extensively characterized and shown to allow prolonged storage as easy-to-handle formulation (dry powder) without loss of nanoparticle activity. Unexpectedly, the nanoparticles' PVA encapsulation/release alters important physicochemical nanoparticle properties and biological activities in a favourable way. Furthermore, we also demonstrate the nanoparticle release to be dependent on the microstructure of the PVA matrix, which is determined by the degree of physical crosslinking through a defined number of freeze/thaw cycles. We show that these defined physically crosslinked PVA hydrogels thus represent sustained release devices for fine-tuned, long-term nanoparticle release in possible therapeutic applications., Statement of Significance: The present paper for the first time describes the embedding of polymeric PEI-based polyplexes and lipopolyplexes into poly(vinyl alcohol) (PVA) hydrogels, to establish novel Nanoparticles-in-Microparticle Delivery Systems (NiMDS). Through modification of various parameters including different PVA molecular weights and concentrations, different emulsifiers and defined numbers of freeze-thaw cycles for physical PVA crosslinking, sustained release devices are also obtained. Beyond favourable alterations of important physicochemical/biological nanoparticle properties and the possibility for prolonged storage as easy-to-handle formulation (dry powder), we show that these NiMDS also allow the tailormade, fine-tuned, long-term release of fully active nanoparticles in possible therapeutic applications., (Copyright © 2016 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.)

The influence of closantel on the rheological and physicochemical properties (particle size and by UV-Vis absorption spectroscopy) of PVA aqueous solutions is studied here. About 1% PVA aqueous solutions were prepared by varying the closantel content. The increase of closantel content led to a reduction in the particle size of final solutions. All the solutions were buffered at pH 7.4 and exhibited shear-thinning behavior. Furthermore, in oscillatory flow, a "solid-like" type behavior was observed for the sample containing 30 μg/mL closantel. Indicating a strong interaction between the dispersed and continuous phases and evidencing an interconnected network between the nanoparticle and PVA, this sample also showed the highest shear viscosity and higher shear thinning slope, indicating a more intrincate structure disrupted by shear. In conclusion, PVA interacts with closantel in aqueous solution and the critical concentration for closantel encapsulation by PVA was about 30 μg/mL; above this concentration, the average particle size decreased notoriously which was associated to closantel interacting with the surface of the PVA aggregates and thus avoiding to some extent direct polymer-polymer interaction.

Peptide (insulin) loaded nanoparticles (NPs) have been embedded into buccal chitosan films (Ch-films-NPs). These films were produced by solvent casting and involved incorporating in chitosan gel (1.25% w/v), NPs-Insulin suspensions at three different concentrations (1, 3, and 5mg of NPs per film) using glycerol as plasticiser. Film swelling and mucoadhesion were investigated using 0.01M PBS at 37°C and texture analyzer, respectively. Formulations containing 3mg of NPs per film produced optimised films with excellent mucoadhesion and swelling properties. Dynamic laser scattering measurements showed that the erosion of the chitosan backbone controlled the release of NPs from the films, preceding in vitro drug (insulin) release from Ch-films-NPs after 6h. Modulated release was observed with 70% of encapsulated insulin released after 360h. The use of chitosan films yielded a 1.8-fold enhancement of ex vivo insulin permeation via EpiOral™ buccal tissue construct relative to the pure drug. Flux and apparent permeation coefficient of 0.1μg/cm(2)/h and 4×10(-2)cm(2)/h were respectively obtained for insulin released from Ch-films-NPs-3. Circular dichroism and FTIR spectroscopy demonstrated that the conformational structure of the model peptide drug (insulin) released from Ch-films-NPs was preserved during the formulation process., (Copyright © 2013 Elsevier B.V. All rights reserved.)

Use of nanoparticles is among the most promising strategies to overcome microbial drug resistance. This review article consists of three parts. The first part discusses the epidemiology of microbial drug resistance. The second part describes mechanisms of drug resistance used by microbes. The third part explains how nanoparticles can overcome this resistance, including the following: Nitric oxide-releasing nanoparticles (NO NPs), chitosan-containing nanoparticles (chitosan NPs), and metal-containing nanoparticles all use multiple mechanisms simultaneously to combat microbes, thereby making development of resistance to these nanoparticles unlikely. Packaging multiple antimicrobial agents within the same nanoparticle also makes development of resistance unlikely. Nanoparticles can overcome existing drug resistance mechanisms, including decreased uptake and increased efflux of drug from the microbial cell, biofilm formation, and intracellular bacteria. Finally, nanoparticles can target antimicrobial agents to the site of infection, so that higher doses of drug are given at the infected site, thereby overcoming resistance., (© 2013.)

Lipid-polymer hybrid nanoparticles (LPNs) are core-shell nanoparticle structures comprising polymer cores and lipid/lipid-PEG shells, which exhibit complementary characteristics of both polymeric nanoparticles and liposomes, particularly in terms of their physical stability and biocompatibility. Significantly, the LPNs have recently been demonstrated to exhibit superior in vivo cellular delivery efficacy compared to that obtained from polymeric nanoparticles and liposomes. Since their inception, the LPNs have advanced significantly in terms of their preparation strategy and scope of applications. Their preparation strategy has undergone a shift from the conceptually simple two-step method, involving preformed polymeric nanoparticles and lipid vesicles, to the more principally complex, yet easier to perform, one-step method, relying on simultaneous self-assembly of the lipid and polymer, which has resulted in better products and higher production throughput. The scope of LPNs' applications has also been extended beyond single drug delivery for anticancer therapy, to include combinatorial and active targeted drug deliveries, and deliveries of genetic materials, vaccines, and diagnostic imaging agents. This review details the current state of development for the LPNs preparation and applications from which we identify future research works needed to bring the LPNs closer to its clinical realization., (Copyright © 2013 Elsevier B.V. All rights reserved.)

Myocardial ischemia (MI) remains one of the leading causes of death worldwide. Angiogenic therapy with the vascular endothelial growth factor (VEGF) is a promising strategy to overcome hypoxia and its consequences. However, from the clinical data it is clear that fulfillment of the potential of VEGF warrants a better delivery strategy. On the other hand, the compelling evidences of the role of oxidative stress in diseases like MI encourage the use of antioxidant agents. Coenzyme Q10 (CoQ10) due to its role in the electron transport chain in the mitochondria seems to be a good candidate to manage MI but is associated with poor biopharmaceutical properties seeking better delivery approaches. The female Sprague Dawley rats were induced MI and were followed up with VEGF microparticles intramyocardially and CoQ10 nanoparticles orally or their combination with appropriate controls. Cardiac function was assessed by measuring ejection fraction before and after three months of therapy. Results demonstrate significant improvement in the ejection fraction after three months with both treatment forms individually; however the combination therapy failed to offer any synergism. In conclusion, VEGF microparticles and CoQ10 nanoparticles can be considered as promising strategies for managing MI., (Copyright © 2013 Elsevier B.V. All rights reserved.)

X-ray diffraction (XRD), scanning electron microscopy (SEM) and transmission electron microscopy (TEM) were used to investigate the structural, surface and particles properties of a series of zinc oxides (ZnO) doped with polyvinyl alcohol (PVA) that were prepared using the sol-gel method. The results demonstrated that the crystallinity of the catalysts decreased as the PVA content increased beyond 5 PVA/ZnO. However, on raising the calcination temperature up to 500 °C, the average crystal size of the PVA/ZnO nanoparticles increased. Next Pyridine adsorption was used to measure the surface acidity of the catalysts, and the results showed that doping ZnO with PVA and raising the calcination temperature to 500 °C increased the catalyst's surface acidity. Furthermore, the data indicates that raising the ratio of the Brønsted to Lewis acid sites enhanced the catalytic activity for the synthesis of coumarin derivatives. We concluded that the structural and acidity characteristics of the catalysts under study had a significant impact on the catalytic activity. Furthermore, a study examining the biological activity of ZnO/PVA and pure ZnO revealed that 5PVA/ZnO performed the best in terms of improving the kidney functions of diabetic rats. [ABSTRACT FROM AUTHOR]

In the present work, flexible polymeric nanocomposite film of poly(vinyl alcohol)/poly(ethylene glycol) (PVA–PEG) blend filled with aluminum (Al)-doped zinc oxide (AZO) nanoparticles has been successfully synthetized and characterized. The solution casting technique was used to prepare pure PVA–PEG polymeric blend and polymeric blend nanocomposite (PNC) films filled with different concentrations of AZO nanoparticles. The morphological, structural and optical properties of AZO NPs and PNC films were investigated using different techniques such as X-ray diffraction (XRD) scanning electron microscopy (SEM), transmission electron microscopy (TEM) spectroscopy and UV–VIS–NIR spectrophotometer. The XRD results shows that nanoparticles are well distributed in the host blend matrix. TEM observation reveals an average particle size about 49 nm. The contact angle analysis was carried out for PNC films to investigate the effect of AZO filling upon the nanocomposite water wettability. Loading PNC with nanopowder AZO influences their electrical optical properties. The addition of AZO nanoparticles in the polymeric blend reduces its band gap and increases its DC electrical conductivity. The antibacterial activity of the prepared nanocomposite films was tested against various pathogenic bacteria including two types of gram-positive bacteria (Staphylococcus aureus (S. aureus) and Bacillus) and two types of gram-negative bacteria (Pseudomonas aeruginosa (P. aeruginosa) and Escherichia coli (E. coli)). The assay results suggested that the pure blend film has no activity against all types of bacteria. While filled PNC films exhibit a significant antibacterial activity against S. aureus, Bacillus and P. aeruginosa bacteria, they have no any activity against E. coli bacteria. This activity is improved with increasing the filler concentrations in blend matrix. Finally, the obtained results suggest that the prepared PNC films can be a potential multifunctional candidate for different applications, especially optoelectronic devices and biomedical uses. [ABSTRACT FROM AUTHOR]

Abstract X-ray diffraction (XRD), scanning electron microscopy (SEM) and transmission electron microscopy (TEM) were used to investigate the structural, surface and particles properties of a series of zinc oxides (ZnO) doped with polyvinyl alcohol (PVA) that were prepared using the sol-gel method. The results demonstrated that the crystallinity of the catalysts decreased as the PVA content increased beyond 5 PVA/ZnO. However, on raising the calcination temperature up to 500 °C, the average crystal size of the PVA/ZnO nanoparticles increased. Next Pyridine adsorption was used to measure the surface acidity of the catalysts, and the results showed that doping ZnO with PVA and raising the calcination temperature to 500 °C increased the catalyst’s surface acidity. Furthermore, the data indicates that raising the ratio of the Brønsted to Lewis acid sites enhanced the catalytic activity for the synthesis of coumarin derivatives. We concluded that the structural and acidity characteristics of the catalysts under study had a significant impact on the catalytic activity. Furthermore, a study examining the biological activity of ZnO/PVA and pure ZnO revealed that 5PVA/ZnO performed the best in terms of improving the kidney functions of diabetic rats.

The goal of this study is to synthesize nanocomposite PVA/ Co0.2Zn0.2Cd0.6Fe2O4 films with varying contents of Co0.2Zn0.2Cd0.6Fe2O4 nanoparticles (x = 0, 0.2, 0.4, 0.6, 0.8) to improve the structural, optical, and mechanical characteristics of the examined materials. Casting technique is used to prepare PVA/ Co0.2Zn0.2Cd0.6Fe2O4 films. X-ray diffraction, FTIR, UV–Vis spectroscopy, and Vickers Hardness were used to examine the effect of magnetic nanoparticle content on the structural, optical, and mechanical characteristics of PVA nanocomposite films. The refractive index rises from 1.4967 for pure PVA to 7.6511 for PVA + 0.8Co0.2Zn0.2Cd0.6Fe2O4, allowing it to be employed in a variety of applications such as solar cell construction. Because of the presence of ferrite in the glass matrix, the average hardness values enhanced and increased from 90.7 to 114.2 MPa. The stress exponent (n) varies from 1.12 to 3.33, with grain boundary sliding as the deformation mechanism for x = 0, viscous glid for x = 0.2, 0.4, and 0.6, and dislocation climb for x = 0.8 nanocomposite thin films. [ABSTRACT FROM AUTHOR]

This work investigates the impact of hybrid aluminum oxide and titanium dioxide nanoparticles (Al 2 O 3 /TiO 2 NPs) on the properties of polyvinyl alcohol (PVA) and polyethylene glycol (PEG) nanocomposite films fabricated via solution casting. Transmission electron microscopy (TEM) analysis revealed an average crystallite size of 25–30 nm for the Al 2 O 3 and TiO 2 , respectively. The X-ray diffraction (XRD) analysis revealed that the addition of hybrid Al 2 O 3 /TiO 2 decreases the crystallinity degree of the PVA/PEG blend. Fourier Transform Infrared (FT-IR) analysis revealed that the main vibrational peaks of the PVA/PEG composite exhibited random variations upon filling with Al 2 O 3 /TiO 2 nanoparticles. UV–Vis–NIR spectroscopy showed a decrease in transmittance and a new absorption peak at higher wavelengths with increasing nanoparticle concentration. The optical bandgap (E g) calculated from the spectra also decreased. Dielectric properties, impedance, and AC conductivity measured at room temperature displayed significant enhancements with increasing nanoparticle content. Analysis of the impedance components (Z′ and Z″) facilitated the determination of the equivalent electrical circuit for each sample. These findings demonstrate the potential of these nanocomposite films with improved electrical and optical properties for applications in optoelectronic devices. [ABSTRACT FROM AUTHOR]

In this study, nanofibers were produced by the electrospinning method by adding 1%, 3%, 5%, and 7% silver nanoparticles (Ag NPs) into the polyvinyl alcohol/sodium caseinate (60/40, w/w) mixture. Electrospun materials were cross‐linked by immersion in a glutaraldehyde bath. Thus, antibacterial wound dressings that could be used on exuding wounds were developed. According to the scanning electron microscopy images of nanofibers, the cross‐linking process by immersion method did not cause negative effects such as breakage or adhesion on the surface of fibers. The cross‐linking of nanofibers was demonstrated by the presence of acetal linkages by Fourier‐transform infrared spectroscopy analysis. The cross‐linking process significantly improved the thermal properties of the nanofibers. The lowest crystallinity calculated in the differential scanning calorimeter was observed in the 3% Ag NP‐added nanofiber with a value of 1.83%. It exhibited the lowest total soluble matter content with a value of 11.98% owing to its high cross‐linking density. In addition, the 3% Ag NP‐added nanofiber, which had the highest toughness and ductility, displayed the highest tensile stress with 3.5 MPa and the highest tensile strain with 7.53%. Moreover, it showed 78.11% cell viability on the L929 fibroblast cell line at the end of the 24th hour. It was indicated that although the electrospun mats maintained 100% antibacterial effectiveness, they could not be used as a wound dressing for 48 h. It was reported that only 3% Ag NP‐added nanofiber could be used as a 100% effective antibacterial wound dressing for both Escherichia coli and Staphylococcus aureus provided that it was renewed every 24 h. Consequently, it was notified that cross‐linking by the immersion method can be used in biomedical applications. Highlights: The antibacterial effects of Ag NP‐doped PVA/NaCAS electrospun mats were significant.The cross‐linking process did not induce toxic effects some of the nanofibers.High cross‐linking density was observed in the nanofibers.The swelling property of nanofibers is a good feature required in an ideal wound dressing. [ABSTRACT FROM AUTHOR]

This work describes how to use the solution casting method to add varying amounts (0, 1, 2, 3, and 4) of Y2O3 and SrCO3 nanoparticles (NPs) to polyvinyl alcohol (PVA) composites. The optical microscopy images showed the formation of networked channels inside the polymeric matrix as electrically charged particles, which became more intense at higher nanoparticle concentrations. With the use of field emission scanning electron microscopy (FESEM), the surface of the nanocomposite was examined. The Y2O3 and SrCO3 nanoparticles were found to be consistently and equally distributed throughout the PVA polymer matrix. Fourier transformation spectroscopy (FTIR) was used to analyses the structural characteristics of the nanocomposite and gather data on molecular vibration. The polymer matrix interacted with the additional Y2O3 and SrCO3 nanoparticles, according to FTIR analysis. Physical interactions between Y2O3 and SrCO3 nanoparticles and the PVA polymer matrix have been demonstrated by the FTIR analysis. The dielectric constant and loss were found to be significant of (PVA/Y2O3/SrCO3) nanocomposite decrease with increasing of frequency while, they are increase with content ratio of Y2O3 and SrCO3 NPs. The A.C. conductivity of (PVA/Y2O3/SrCO3) nanocomposite increase with increasing of frequency and concentration of Y2O3 and SrCO3 NPs. Finally, the PVA/Y2O3/SrCO3 nanocomposites were tested for the antibacterial against both gram positive Staphylococcus aureus (S. aureus) and gram-negative Escherichia coli (E. coli). The result obtained that the inhibition zone diameter increased with increasing Y2O3 and SrCO3 NPs. The PVA/Y2O3/SrCO3 nanocomposite exhibited antibacterial activity. [ABSTRACT FROM AUTHOR]

Due to the harmful effects of ionizing radiation, shielding has become a crucial topic for radiation protection. Finding effective, non-toxic and low-cost shielding materials is imperative in ensuring the safety of individuals exposed to ionizing radiation. Whether a material is effective in shielding against radiation depends on the linear attenuation coefficient. In this study, linear attenuation coefficients were calculated using the MCNPX code for energy values of 81 keV (Ba-133), 140 keV (Tc-99m), 662 keV (Cs-137), 1173 keV, and 1332 keV (Co-60) by incorporating Bentonite Clay (BC) nanoparticles and micro-sized particles as additives into a Polyvinyl Alcohol (PVA) matrix. BC particles with a density of 50% were added to the PVA matrix using LAT and U cards. Simulations were performed with a monoenergetic source emitting 107 particles and a narrow beam geometry, and the counts of particles with diameters of 50 nanometers and 50 micrometers were calculated using the F4 tally. When the results obtained from the simulation were compared, it was observed that as the diameters of the added particles decreased, their effectiveness in radiation shielding increased for each energy value. Among them, the 50 nm BC particles added at a rate of 50% in PVA showed the highest effect at 1332 keV, with a 9.5% increase compared to 50 µm BC particles. [ABSTRACT FROM AUTHOR]

In this research, the thermal and electrical characteristics of a polymer matrix composite with polyvinyl alcohol as a constituent (PVA) integrated with nanoscale silver particles (Ag NPs) were studied. The PVAAg NPs composite samples were meticulously fabricated through the casting process, incorporating varying weight percentages of nanosilver 0 %, 1 %, 3 %, and 5 %. The experimental findings reveal intriguing trends. Specifically, as the applied electric field's frequency increases, the dielectric constant of the PVA-Ag NPs composite decreases while the dissipation factor increases, indicative of altered electrical behavior. Furthermore, there is a noticeable augmentation in AC electrical conductivity. Notably, as the concentration of Ag NPs increases, the composite's dielectric constant and dissipation factor show a proportional rise, unveiling the interplay relationship between silver nanoparticle content and these characteristics. [ABSTRACT FROM AUTHOR]

A set of polymer-embedded, two-colored nanocomposites were prepared where the co-existing emission peaks (~578 nm and ~650 nm) had different ratios at their emission thresholds. The nanocomposite samples were simultaneously excited by a 405 nm laser, and the growth of photoluminescence intensities was studied as a function of excitation intensity. The two peaks showed different growth evolution mechanisms. The factors impacting this difference could be (1) energy transfer between the two sized nanoparticles; (2) relaxation mechanism of smaller nanoparticles; and (3) material properties of the polymer. [ABSTRACT FROM AUTHOR]

In this study, it is aimed to produce a non‐carcinogenic and environmentally friendly biodegradable multi‐functional PVA‐based nanocomposite by improving its electrical properties and mechanical strength. For this purpose, BaO nanoparticles produced by the co‐precipitation method, have been added to the PVA matrix between 0.5% and 5% by mass, and thick film nanocomposites have been produced. The structural properties of the samples and the doping particle have been investigated by FTIR, SEM, and XRD. While electrical measurements have been carried out by an impedance analyzer at room temperature between 20 Hz and 15 MHz frequency, tensile tests have been performed by a mechanical tensile device. The addition of 5% BaO nanoparticles not only increased the energy storage capability of PVA significantly (117%) but also managed to reduce the loss factor considerably (77%). Moreover, compared to other samples, PVA/5% BaO nanocomposite also stands out with its higher ac conductivity within the mid‐and high‐frequency range. Furthermore, the 5% BaO nanoparticle additive provided a serious benefit to the mechanical strength of PVA by improving its Young's modulus, toughness, and stress at the break at different rates. As a result, the BaO nanoparticle additive makes PVA a more functional material as well as more technologically desired. [ABSTRACT FROM AUTHOR]

The objective of this work was to formulate PVA films with the addition of modified phenols, chitosan, silver, or copper nanoparticles with fungistatic and bacteriostatic activity. The films were characterized by Fourier transform infrared spectroscopy, thermogravimetry analysis, differential scanning calorimetry, and scanning electron microscopy. The bacteriostatic activity against Salmonella gallinarum and Lactobacillus acidophilus, and the fungistatic activity against Penicillium acidophilus were determined. The results indicated that the addition of phenols enhanced the effect on the stability of the chemical structure of the PVA film. PVA films with modified bioactives and nanoparticles inhibited the colonization of the microorganisms tested, indicating germicidal control. [ABSTRACT FROM AUTHOR]

Areca nut or Areca catechu L is a plant that has many benefits, one of which is that it can be used as medicine. There are secondary metabolite compounds in betel nut. The presence of this secondary metabolite content makes the betel nut skin a high potential as a bioreductant to synthesize silver nanoparticles as an antibacterial. The process of synthesizing silver nanoparticles is carried out with the addition of a stabilizer in the form of Polyvinyl alcohol (PVA). The analysis results obtained using the UV-Vis instrument have wavelengths with variations in the addition of 1%, 3% and 5% PVA, respectively, are 448 nm, 456 nm and 460 nm. In the results of the analysis using XRD, the value of 2θ is silver nanoparticles (PVA 1%): 38,020; 43,930 ; 64,320 ; 77,270. silver nanoparticles (PVA 3%): 38,230; 44,270 ; 64,610 ; 77,500. And silver nanoparticles (PVA 5%) are 38,100 ; 44,240 ; 64,460 ; 77,370. For analysis using SEM, the particle size obtained with the help of the Imegej and OriginLab 8.5 applications, namely at AgNPS + PVA 1% is 28 nm - 31 nm. Agnps + PVA 3% ranged from 26 nm – 29 nm. And Agnps + PVA 5% has a size of 19 nm – 22 nm. For the results of FTIR data, the specific absorption peaks of Ag nanoparticles are located at frequencies of 412.23 cm-1, 453.57 cm-1, and 476.84 cm-1. Then in the antibacterial test, silver nanoparticles were used with the addition of 5% PVA. The size of the clear zone obtained in the test for E. coli bacteria is 11.2 mm and for S. Aureus it is 13 mm

Coffee parchment is one of the residues generated in coffee processing and has been poorly explored for value-added applications. It has been reported that coffee parchment has a high cellulose content (40–49%). Cellulose has been studied in many fields and specifically regenerated cellulose has been explored for many applications. Then, in this work a simple method for obtaining regenerated cellulose nanoparticles (RCNPs) from delignified coffee parchment, was determined. A complete physicochemical characterization of RCNPs obtained is presented, FTIR showed high cellulose purity, and XRD analysis showed high crystallinity of cellulose II. TEM images revealed that nanoparticles have spherical morphology. TGA showed good thermal stability and DLS allowed to determine the stability of suspension and the Z-average of the particles. The application of RCNPs on film formation was also evaluated when blended with PVA and Glycerol showing good mechanical properties with potential application on food packing. [ABSTRACT FROM AUTHOR]

A scaffold that replicates the physicochemical composition of bone at the nanoscale level is a promising replacement for conventional bone grafts such as autograft, allograft, or xenograft. However, its creation is still a major challenge in bone tissue engineering. The fabrication of a fibrous PVA-HA/Sr matrix made of strontium (Sr)-substituted hydroxyapatite from the shell of Pomecea canaliculate L. (golden apple snail) is reported in this work. Since the fabrication of HAp from biogenic resources such as the shell of golden apple snail (GASs) should be conducted at very high temperature and results in high crystalline HAp, Sr substitution to Ca was applied to reduce crystallinity during HAp synthesis. The resulted HAp and HA/Sr nanoparticles were then combined with PVA to create fibrous PVA-HAp or PVA-HA/Sr matrices in 2 or 4 mol % Sr ions substitution by electrospinning. The nanofiber diameter increased gradually by the addition of HAp, HA/Sr 2 mol %, and HA/Sr 4 mol %, respectively, into PVA. The percentage of the swelling ratio increased and reached the maximum value in PVA-HA/Sr-4 mol %, as well as in its protein adsorption. Furthermore, the matrices with HAp or HA/Sr incorporation exhibited good bioactivity, increased cell viability and proliferation. Therefore, the fibrous matrices generated in this study are considered potential candidates for bone tissue engineering scaffolds. Further in vivo studies become an urgency to valorize these results into real clinical application. [ABSTRACT FROM AUTHOR]

The solution casting process was used to fabricate nanocomposite samples composed of carboxymethylcellulose (CMC), polyvinyl alcohol (PVA), poly(3,4-ethylenedioxythiophene) polystyrene sulfonate (PEDOT:PSS) and filled with varied concentrations of nickel oxide nanoparticles (NiO NPs). The effect of NiO nanoparticles on the structural, optical, and electrical properties of the pure CMC/PVA/PEDOT:PSS mixture was studied and discussed. X-ray diffraction (XRD) and transmission electron microscopy (TEM) analysis revealed that the NiO NPs are cubic in phase and range in size from 10 to 55 nm. The XRD analysis of the incorporated films indicated that the NiO NPs crystallinity increased at expense of the CMC/PVA/PEDOT:PSS composites. Fourier Transform Infrared (FTIR) examination revealed the main absorption vibrational peaks of CMC, PVA, PEDOT:PSS, and Ni-O, whose intensities changed randomly after filling, revealing the intermolecular interaction between the nanocomposite components. The UV and visible range absorption spectra showed a sharp peak around 228 for the pure blend, which can be assigned to the π→π* transition. After being filled with NiO NPs, the nanocomposites produced displayed new peaks at 292 and 422 nm that steadily increased with increasing NiO NPs concentration. The optical energy gap (Eg) was computed, and it was discovered that when the NiO NPs content increased, the Eg decreased (from 4.88 to 4.06 eV). At room temperature and over a wide frequency range, between 10− 1 and 107 Hz, the samples' impedance, AC conductivity, and dielectric qualities were examined. Increased NiO NPs content was seen to gradually enhance dielectric loss (up to 2255), and dielectric constant (up to 311). The AC conductivity of the filled samples is also enhanced and corresponds to Jonscher power law. By analysing impedance components of the Z*, the equivalent electrical circuit for each sample was determined. Because of the considerable improvement in optical and electrical properties, these composite films could compete for usage in optoelectronic applications. [ABSTRACT FROM AUTHOR]

In this work, the one-step synthesis of multicomponent polymer nanocomposites containing zinc oxide and cuprous oxide nanoparticles based on chitosan and polyvinyl alcohol was investigated using underwater pulsed discharge plasma. Direct initiation of electrical discharge between metal electrodes in a polymer solution enables reagent-free obtaining of metal oxide nanoparticles with an average diameter of about 30 nm. Transmission electron microscopy observations showed °that metal oxide nanoparticles uniformly dispersed in polymer matrix. It has been established that a partial destruction of chitosan occurs with the formation of glucosamine, N-acetylglucosamine, and delta-mannitol under the action of the discharge. The polymer film containing 0.35% Cu2O and 3.41% ZnO nanoparticles demonstrated the highest antimicrobial activity Escherichia coli, Staphylococcus albicans, and Bacillus subtilis. [ABSTRACT FROM AUTHOR]

Besides being known by food and perfume industries, vanillin has also important pharmacological properties such as anti-inflammatory and antibacterial activities. The use of magnetic nanoparticles as carriers for a vanillin delivery system is a way to explore its benefits in human beings. In this paper, poly(lactic-co-glycolic acid) (PLGA) nanoparticles stabilized by poly(vinyl alcohol) (PVA) and containing magnetic CoFe2O4 and vanillin have been prepared using a double emulsion-solvent evaporation method. The morphology, particle size, structure, and surface properties of the nanoparticles were investigated by transmission electron microscopy, zeta-potential measurements, X-ray diffractometry, Fourier transform infrared spectroscopy, magnetic hysteresis loops, and thermogravimetric analysis. The spherical nanoparticles presented negative charge, with zeta-potential values ranging from −9.15 to −5.64 mV, high thermal stability, superparamagnetic properties, and excellent encapsulation of the vanillin (around 80%). Accordingly, such PLGA/PVA nanoparticles encapsulating vanillin and CoFe2O4 exhibited the desired features to suggest their potential use as drug delivery systems. PLGA/PVA nanoparticles with CoFe2O4 were synthesized for the targeted delivery of vanillin. The spherical nanoparticles presented negative zeta-potential ranging from −9.15 to −5.64 mV. Encapsulation promoted an increased release rate of vanillin. Analytical validation was used for vanillin quantification. [ABSTRACT FROM AUTHOR]

Hesperidin (HSP) is considered to be the most effective antimicrobial agent against SARS-CoV2 virus. The HSP was loaded onto ZnO nanoparticles that were successfully incorporated, via the hydrothermal method, into polyvinyl alcohol (PVA) for use as food packaging material. The hydrothermal method enabled the bioactive ZnO-HSP to be homogeneously dispersed in the PVA, which significantly increased the thermal stability of the matrix, while decreasing the softening temperature. The water holding capacity and water solubility of the obtained nanocomposites was reduced compared to the PVA. Finally, the ZnO-HSP antimicrobial agent contributed important antibacterial properties to the PVA and increased its antioxidant capacity against Staphylococcus aureus and Escherichia coli pathogens. In addition, the nanocomposites had no cytotoxic/proliferative effects on cancer cells. All results showed promise that the PVA/ZnO-HSP nanocomposites would be an excellent alternative for food packaging applications. [ABSTRACT FROM AUTHOR]

A set of polymer-embedded, two-colored nanocomposites were prepared where the co-existing emission peaks (~578 nm and ~650 nm) had different ratios at their emission thresholds. The nanocomposite samples were simultaneously excited by a 405 nm laser, and the growth of photoluminescence intensities was studied as a function of excitation intensity. The two peaks showed different growth evolution mechanisms. The factors impacting this difference could be (1) energy transfer between the two sized nanoparticles; (2) relaxation mechanism of smaller nanoparticles; and (3) material properties of the polymer.

The aim of the work was to prepare a polymer matrix composite doped by silver nanoparticles and analyze the influence of silver nanoparticles (AgNPs) on polymers' optical and toxic properties. Two different colloids of AgNPs were prepared by chemical reduction. The first colloid, a blue one, contains stable triangular nanoparticles (the mean size of the nanoparticles was ~75 nm). UV–vis spectrophotometry showed that the second colloid, a yellow colloid, was very unstable. Originally formed spherical particles (~11 nm in diameter) after 25 days changed into a mix of differently shaped nanoparticles (irregular, triangular, rod-like, spherical, decahedrons, etc.), and the dichroic effect was observed. Pre-prepared AgNPs were added into the PVA (poly(vinyl alcohol)) polymer matrix and PVA–AgNPs composites (poly(vinyl alcohol) doped by Ag nanoparticles) were prepared. PVA–AgNPs thin layers (by a spin-coating technique) and fibers (by electrospinning and dip-coating techniques) were prepared. TEM and SEM techniques were used to analyze the prepared composites. It was found that the addition of AgNPs caused a change in the optical and antibiofilm properties of the non-toxic and colorless polymer. The PVA–AgNPs composites not only showed a change in color but a dichroic effect was also observed on the thin layer, and a good antibiofilm effect was also observed. [ABSTRACT FROM AUTHOR]

In this work, new samples of PVA-TiO2/Cu nanocomposites were prepared via the casting method. The prepared samples were examined using different analytical methods. An XRD analysis showed the semi-crystalline nature of the PVA polymer, as well as showing a decrease in the degree of the crystallinity of the PVA structure as a result of the addition of the mixed nanoparticles. TEM images indicate the spherical shape of the Cu NPs, with a size ranging from 2 to 22 nm, and the rectangular shape of the TiO2 NPs, with a size ranging from 5 to 25 nm. It was evident via FTIR measurements that there were interactions between the functional groups of the PVA and the TiO2/Cu NPs. The optical properties of the PVA nanocomposites were improved with an increase in the content of the TiO2/Cu nanoparticles, as shown via a UV/Vis analysis. DSC curves showed an improvement in the thermal stability of the PVA-TiO2/Cu nanocomposites after the embedding of the TiO2/Cu nanoparticles. It was evident using impedance spectroscopy that the AC conductivity was improved by adding the TiO2 and Cu nanoparticles to the polymeric matrix. The maximum AC conductivity was found at 1.60 wt.% of TiO2/Cu nanoparticles in the PVA polymer, and this was 13.80 × 10−6 S/cm at room temperature. Relaxation occurred as a result of the charge carrier hopping between the localized state and the correlated barriers hopping model, describing the dominant mechanism, as presented in an electrical modulus analysis. These results indicate that the PVA-TiO2/Cu nanocomposite samples can be used in energy storage capacitor applications and in the alternative separator-rechargeable lithium-ion battery industry. [ABSTRACT FROM AUTHOR]

Pegagan is a plant that plays an important role in health because of its secondary metabolite. However, many secondary metabolites tend to be unstable when exposed to UV light and oxygen such as flavonoid and terpenoid. The purpose of this study was to formulate the ethanolic extract of pegagan leaves into nanoparticle preparations to increase the stability of the extract. Nanoparticle preparations were made using the emulsion solvent evaporation method using Poly-Lactic-Co-Glycolic Acid (PLGA) and polyvinyl alcohol (PVA). PLGA acts as a polymer that will coat the extract and PVA as a stabilizer. Variations in the concentration of PLGA used were 50 mg, 75 mg, and 100 mg, while the concentration of PVA used was 40 mg and the extract concentration was 158 mg. Determination of the best formula is done by looking at the results of the percent encapsulation efficiency obtained from the three formulas, namely 93.68%, 85.35%, and 88.76%, respectively. Based on these results, formula 1 was determined as the best formula. The particle size obtained in the best formula was 288.1667±3.4195 nm, the polydispersity index (PDI) was 0.371±0.0045 and the zeta potential value was -10.6333±0.1154. A physical stability test (cycling test method) of the best formula found a decrease in pH of 0.54 and no organoleptic changes or precipitate formed.

The objective of this work was to formulate PVA films with the addition of modified phenols, chitosan, silver, or copper nanoparticles with fungistatic and bacteriostatic activity. The films were characterized by Fourier transform infrared spectroscopy, thermogravimetry analysis, differential scanning calorimetry, and scanning electron microscopy. The bacteriostatic activity against Salmonella gallinarum and Lactobacillus acidophilus, and the fungistatic activity against Penicillium acidophilus were determined. The results indicated that the addition of phenols enhanced the effect on the stability of the chemical structure of the PVA film. PVA films with modified bioactives and nanoparticles inhibited the colonization of the microorganisms tested, indicating germicidal control.

High dielectric constant nanocomposite polymer films based polyvinyl alcohol (PVA) with different weight ratios of nanoparticles (NPs) TiO2 (1.0, 2.5, 5.0, and 10) are prepared by the casting method. The structure of TiO2 NPs is studied using TEM and XRD spectra, where the FTIR spectra show a strong interaction between PVA and TiO2 NPs. The addition of TiO2 NPs to the composites improves their mechanical properties. The dielectric parameters and AC conductivity are explored in the 10 Hz to 107 Hz frequency range at different temperatures. PVA composite films filled with 5.0 wt% TiO2 NPs exhibit the highest dielectric constant (ε′) reaching up to 26 at 25 °C and 100 Hz. The origins of the enhanced dielectric properties are investigated using theoretical predictions of the effective ε′ of composites. The activation energy of a dielectric relaxation process is computed. As the temperature rises, the relaxation time lengthens slightly. A conduction mechanism is described based on thermally activated electron hops at the Fermi edge. [ABSTRACT FROM AUTHOR]

Bismuth tungstate (Bi2 WO6 ) emerged as one of the most capable chromogenic compounds among transition metal oxide having wide opto-electronic applications. It is an n-type semiconducting material having bandgap around ~2.7eV. Conversely, Nano Composite (NC) materials have been investigated in order to tailor the properties polymers and also to widen the applications. In this context Poly (vinyl alcohol)/ Bismuth tungstate (PVA/Bi2 WO3 ) NC films were prepared with various weight ratio of Bi2 WO6 content viz.0, 0.1, 0.2 0.4, and 0.8 wt%. The solution combustion method was employed to prepare Bi2 WO6 nanoparticles (NPs). Subsequently, synergistic effect of polymer matrix and Bi2 WO6 NPs is characterized and analysed to estimate the enhanced properties. The surface morphology of the NC’s films was explored by Scanning Electron Microscopy (SEM). Elemental analysis is carried out using EDAX. The formation of polymer NC and its microstructural properties were investigated by X-ray diffraction technique and it is revealed that there is formation of orthorhombic phase for Bi2 WO6 NPs with an average size of 35nm. Interaction of NP and PVA is studied using FT-IR spectrometer. The optical constants were evaluated by UV-visible spectrometer and it was found that NC films bandgap energy varied from 5.4 eV to 2.85eV for direct and from 4.57eV to 2.38eV for indirect bandgap. It is anticipated that these unique organic–inorganic NC materials are the emerging functional materials in the field of opto-electronics. [ABSTRACT FROM AUTHOR]

[Display omitted] • Selenium nanoparticles are eco-friendly materials. • PVA-capped selenium nanoparticles (Se-PVA NPs) are stable and can be easily synthesized. • Se-PVA NPs are investigated as carbon steel corrosion inhibitor. • Se-PVA NPs behave as a mixed-type and efficient carbon steel corrosion inhibitor. • Se-PVA NPs are adsorbed on the metal surface and form a protective layer that insulates the surface from the aggressive acidic medium. Selenium nanoparticles capped with polyvinyl alcohol (Se-PVA NPs) have been synthesized by chemical reduction using ascorbic acid as a reducing agent. The synthesized nanoparticles were characterized using XRD, DLS, zeta potential, FT-IR, and TEM analysis and found to be stable. The solution of Se-PVA NPs was used as a carbon steel corrosion inhibitor in 1.0 M H 2 SO 4. The effect of the presence of Se-PVA NPs in the corrosion medium was studied by potentiodynamic polarization and gravimetric analyses In the presence of Se-PVA NPs with a concentration of 600 ppm at 303 K, corrosion inhibition efficiency values of 92.86 % and 92.3 % were recorded by potentiodynamic polarization and gravimetric analysis methods, respectively. Over the Se-PVA NPs concentration range 100–600 ppm, it was found that increasing the concentration increases the inhibition efficiency, while the temperature has an adverse effect, inhibition efficiency values of 80.0 % was recorded at 323 K for the 600 ppm Se-PVA NPs solution. The potentiodynamic polarization measurements suggested that Se-PVA NPs work as a mixed-type inhibitor. The corrosion inhibition process was confirmed by testing the used specimens' metal surface using SEM and AFM techniques, which showed that the acidic medium's negative impact (distortion and roughness) on the carbon steel surface was reduced significantly in the presence of Se-PVA NPs. The inhibitor's adsorption on the metal surface was studied. It obeys the Langmuir isotherm with a mixed-type adsorption process. The related kinetic and thermodynamic parameters were investigated. [ABSTRACT FROM AUTHOR]

In light of the need to create new materials that are safe for use in biomedical applications like wound healing and tissue engineering, a unique nanocomposite was formulated and produced in the current investigation. A biocompatible hydrogel was created using natural polymers xanthan gum (XG) and alginate (Alg). In order to enhance the mechanical characteristics of the natural polymer-based hydrogels, polyvinyl alcohol (PVA) was added to the hydrogel matrix. Subsequently, the XG-Alg hydrogel/PVA structure was combined with ZnMnFe 2 O 4 nanoparticles in order to augment the antibacterial efficacy of the biomaterial. The XG-Alg hydrogel/PVA/ZnMnFe 2 O 4 nanocomposite was analyzed using XRD, EDX, FT-IR, TGA, and FE-SEM techniques to determine its properties. In addition, the mechanical properties of the pure hydrogel were compared to those of the XG-Alg hydrogel/PVA/ZnMnFe 2 O 4 nanocomposite. The nanocomposite exhibited a biocompatibility of 96.45 % and 94.32 % with HEK293T cell lines after 24 h and 48 h of incubation, respectively, in biological evaluations. Furthermore, a significant antibacterial efficacy was demonstrated against both gram-positive S. aureus and gram-negative E. coli bacteria. The findings suggest that the developed XG-Alg hydrogel/PVA/ZnMnFe 2 O 4 nanocomposite has promising qualities for use in biomedical fields, such as tissue engineering. [ABSTRACT FROM AUTHOR]

Copper dioxide (CuO) nanoparticles and Multiwall carbon nanotubes (MWCNTs) filled poly(vinyl alcohol) (PVA) and poly(vinyl pyrrolidone) (PVP) blend matrix (50/50 wt%) based polymer nanocomposites (PNCs) (i.e., PVA/PVP:(15-x)CuO(x)MWCNTs for x = 0,1,5,7.5, 10,14, and 15wt%) have been prepared employing the solution-cast method. The morphologies of these PNCs are semicrystalline, according to an X-ray diffraction investigation. The FTIR, SEM, and AFM measurements of PNCs were used to investigate the development of the miscible mix, polymer-polymer and polymer–nanoparticle interactions, and the influence of CuO and MWCNTs nanofillers on the morphology aspects on the main chain of PVA/PVP blend. The nanofiller dispersion signposting for x = 14 wt% nanoloading in the PVA–PVP blend matrix significantly enhances the crystalline phase, diminishing the optical energy gap to 2.31 eV. The DC conductivity values augment with the upsurge in nanofiller level for maximum x = 14 wt%. The dielectric and electrical characteristics of these PNCs are investigated for an applied frequency range from 1 kHz to 1 MHz. The enhancement in the nanofiller level upto x = 14 wt% in the PVA/PVP matrix leads to the development of percolating network through the PNCs. These factors boost the dielectric permittivity values substantially, owing to the decrease in the nano-confinement phenomenon. The rise in applied frequency reduces dielectric permittivity and impedance values and enhances ac electrical conductivity. These PNCs having good dielectric and electrical characteristics can be used as frequency tunable nanodielectric material in electronic devices. [ABSTRACT FROM AUTHOR]

Ag nanoparticles (AgNPs) and Ag/polyvinyl alcohol (PVA) nanofiber composites were synthesized via chemical reduction and electrospinning methods, respectively. The filler mass of AgNPs in the Ag/PVA nanofiber composites was varied from 0.025 to 0.125 g. X-ray diffraction (XRD) analysis was used to determine the structure, crystal size, and lattice parameter of powdered AgNPs. Fourier transform infrared (FTIR) spectroscopy was used to determine the functional groups of the samples. Scanning electron microscopy (SEM) and transmission electron microscopy (TEM) were used to observe the fiber diameter, particle size, and nanoparticle size distribution in the Ag/PVA composites. The XRD analysis showed that the AgNPs were ~ 18.9 nm in diameter, consistent with TEM observations. FTIR analysis indicated the presence of Ag–O functional groups in the composites for all mass variations of AgNPs, as indicated by a peak at 490–510 cm−1. The emergence of this functional group confirmed the presence of AgNPs in the composites. SEM and TEM analyses showed that the diameter of the Ag/PVA nanofibers substantially increased from 150.5 (AgNPs mass 0.025 g) to 190.5 nm (AgNPs mass 0.125 g). AgNPs were successfully dispersed in a PVA polymer matrix network appear to have agglomerated at some those network points. [ABSTRACT FROM AUTHOR]