Presence Of Polyvinylpyrrolidone Research Articles

Effects of polyvinylpyrrolidone on the crystallization of amorphous griseofulvin: fracture and molecular mobility

This study aims to investigate the fracture, molecular mobility and crystallization behaviors of amorphous griseofulvin (GSF) in the presence of polyvinylpyrrolidone (PVP). In the presence of 10%(w/w) PVP K90, the fracture resistance of griseofulvin was greatly improved. Compared with the pure GSF system, the average fracture temperature of the griseofulvin–PVP K90 system was decreased to approximately −6.1°C. More importantly, a statistical study revealed that the direct connection between fracture and nucleation of griseofulvin was weakened in the presence of PVP K90. This study also explored the effects of PVP K90 on the molecular dynamics and crystallization behaviors of amorphous GSF. In the presence of PVP K90, the crystal growth kinetics and molecular dynamics were both slowed down. Interestingly, needle-like crystal growth was observed, exhibiting approximately the same rates as the bubble-induced process. These findings are important for understanding the complex mechanisms of physical stability of polymer-based amorphous solid dispersions.

Boosting the photocatalytic activity of bismuth vanadate (BiVO4) via optimization of the internal polarization

Photocatalytic performance can be improved by optimizing the morphology and surface texture of the photocatalyst or forming different p-n and/or n-n heterojunctions. Although the heterojunction system enhances photocatalytic property; however, an internal spontaneous polarization electric field may be much more effective due to the separation of electron-hole pairs when the polarization field forces them to move in different directions. The present study demonstrated this insight where the BiVO4 synthesis condition and polarization field forces were controlled via homogeneous precipitation in the presence of polyvinylpyrrolidone (PVP). The as-synthesized BiVO4 photocatalysts' structure and morphology were investigated using XRD, SEM, Raman, DRS, and PL. The result revealed that the increase of PVP concentration reformed the shaping to the truncated bipyramid-like shape and creates a spontaneous internal polarization that enhanced BiVO4 photocatalytic performance. The photocatalytic activity of BiVO4 was evaluated by monitoring the photocurrent enhancement using chronoamperometry, electrochemical impedance spectra and the photodegrading of methylene blue (MB) aqueous solution to harmless compounds in the presence of light. The spontaneous polarization between the different facets of BiVO4 crystal enhances the e−/h+ separation during internal facets homojunction and leads to four times photocurrent enhancement and the MB photocatalytic degradation rate increased from 0.43 to 1.92 min−1.

Copper oxide(I) nanoparticle-modified cellulose acetate membranes with enhanced antibacterial and antifouling properties.

Cellulose acetate membranes exhibit a potential to be applied in hemodialysis. However, their performance is limited by membrane fouling and a lack of antibacterial properties. In this research, copper oxide (I) nanoparticles were fabricated in situ into a cellulose acetate matrix in the presence of polyvinylpyrrolidone (pore-forming agent) and sulfobetaine (stabilising agent) to reduce the leakage of copper ions from nano-enhanced membranes. The influence of nanoparticles on the membrane structure and their antibacterial and antifouling properties were investigated. The results showed that incorporating Cu2O NPs imparted significant antibacterial properties against Staphylococcus aureus and fouling resistance under physiological conditions. The Cu2O NPs-modified membrane could pave the way for potential dialysis applications.

Chemically engineered nano selective silver shapes: Novel synthesis and their potential activity as anti-candida agents

Oral candidiasis (OC) is an infection of oral mucosa caused by fungal overgrowth, especially Candida albicans due to its ability to form biofilms and the increased expression of virulence factors. In the present study, Ag Nano sphere & Ag Nano triangle were newly synthesized using Juniperus drupacea L leaves extract to combat the OC infections. Ag Nano sphere & Ag Nano triangle antifungal activity, mechanism of action against OC, and cytotoxic effect in L929 (ATCC CCL-1 NCTC) fibroblast cell monolayers were evaluated. The J. drupacea phytochemical analysis revealed the presence of three major compounds: α-pinene (34.27 %), thymol methylether (15.20 %) and camphor (9.01 %). The proposed synthesis approach includes the reduction of Ag+ by Juniperus drupacea L leaves extract to form Ag Nano spheres. One the other hand, the presence of polyvinylpyrrolidone (PVP) in the reaction mixture led to obtaining Ag Nano triangle shapes. The minimal fungicidal concentration (MFC) and minimal biofilm eradication concentration (MBEC) assays revealed the higher antifungal effect of Ag Nano sphere when compared to Ag Nano triangle. MFC of Ag Nano sphere and Nano triangle reached 62.5 and 125 µg/mL respectively. While MBECs were ranged between 4 and 32 and 16–64 µg/mL upon using Ag Nano sphere and Nano triangle respectively. The possible mechanism of action of the synthesized Ag Nano shapes was the attributed to the direct effect on the cell membrane especially after 6 h incubation. In vitro cytotoxic effect of the prepared Ag-Nano sphere on cell proliferation using L929 (ATCC CCL-1 NCTC) fibroblast cell monolayers suggested the Ag-Nano spheres are safe for possible biomedical application.

Effect of Polyvinylpyrrolidone on the Structure Development, Electrical, Thermal, and Wetting Properties of Polyvinylidene Fluoride-Expanded Graphite Nanocomposites.

Polyvinylidene fluoride (PVDF)-expanded graphite (ExGr) nanocomposites have been prepared by solution blending and melt processing methods. In the presence of polyvinylpyrrolidone (PVP), enhanced dispersion of graphite nanosheets (GNSs) in the PVDF matrix, as suggested by field emission scanning electron microscopy analysis, results in very low electrical percolation threshold (0.3 wt % ExGr). X-ray diffraction, Fourier transform infrared spectroscopy, and differential scanning calorimetry (DSC) analyses confirm the coexistence of electroactive gamma and nonpolar alpha phases. Wrapping of PVP chains around GNSs reduces the crystallinity in PVDF-ExGr nanocomposites in comparison to that in neat PVDF films, as evidenced by DSC analysis. Thermogravimetric analysis confirms enhanced thermal stability of PVDF-ExGr nanocomposites above 500 °C mainly attributed to the PVP-assisted dispersion of GNSs. The water contact angle of solution-blended PVDF-ExGr nanocomposite films increases with and without PVP in comparison to that of the neat PVDF film. Compression-molded PVDF-ExGr nanocomposites also exhibit electroactive gamma and nonpolar alpha phases of PVDF with reduction in electrical conductivity compared to solvent-cast films.

Hydroxypropyl Methylcellulose Bioadhesive Hydrogels for Topical Application and Sustained Drug Release: The Effect of Polyvinylpyrrolidone on the Physicomechanical Properties of Hydrogel.

Hydrogels are homogeneous three-dimensional polymeric networks capable of holding large amounts of water and are widely used in topical formulations. Herein, the physicomechanical, rheological, bioadhesive, and drug-release properties of hydrogels containing hydroxypropyl methylcellulose (HPMC) and polyvinylpyrrolidone (PVP) were examined, and the intermolecular interactions between the polymers were explored. A three-level factorial design was used to form HPMC-PVP binary hydrogels. The physicomechanical properties of the binary hydrogels alongside the homopolymeric HPMC hydrogels were characterized using a texture analyzer. Rheological properties of the gels were studied using a cone and plate rheometer. The bioadhesiveness of selected binary hydrogels was tested on porcine skin. Hydrophilic benzophenone-4 was loaded into both homopolymeric and binary gels, and drug-release profiles were investigated over 24 h at 33 °C. Fourier transform infrared spectroscopy (FTIR) was used to understand the inter-molecular drug-gel interactions. Factorial design analysis supported the dominant role of the HPMC in determining the gel properties, rather than the PVP, with the effect of both polymer concentrations being non-linear. The addition of PVP to the HPMC gels improved adhesiveness without significantly affecting other properties such as hardness, shear-thinning feature, and viscosity, thereby improving bioadhesiveness for sustained skin retention without negatively impacting cosmetic acceptability or ease of use. The release of benzophenone-4 in the HPMC hydrogels followed zero-order kinetics, with benzophenone-4 release being significantly retarded by the presence of PVP, likely due to intermolecular interactions between the drug and the PVP polymer, as confirmed by the FTIR. The HPMC-PVP binary hydrogels demonstrate strong bioadhesiveness resulting from the addition of PVP with desirable shear-thinning properties that allow the formulation to have extended skin-retention times. The developed HPMC-PVP binary hydrogel is a promising sustained-release platform for topical drug delivery.

The performance of hypochlorous acid modified Ag nanoparticle-based assay in the determination of total antioxidant capacity of Boswellia Serrata and Aronia

In this study, the SNPAC method was developed by using hypochlorous (ClO−) at pH 9.3. Polyvinylpyrrolidone (PVP) was used as a stabilizer. The existence of HOCl enables to formation stronger and more stable yellow emission which gives sensitivity. As a result, lower LOD and LOQ values were achieved by the AgNP–HOCl method. The obtaining lower values was attributed to the reoxidation of silver atoms with ClO− ions in the presence of PVP. The newly modified method was applied to the total antioxidant capacity (TAC) measurement of Boswellia Serrata, Aronia Melanocarpa tea, and juice. The results were compared with the results obtained by application of CUPRAC (Cupric ion Reducing Antioxidant Capacity) and FRAP (Ferric Reducing Antioxidant Power) assays. The TAC values of Boswellia Serrata, Aronia Melanocarpa tea, and juice were found as 6.18, 137.98, and 12.08 mmol TEAC/kg, respectively.

Polyacrylic acid/ polyvinylpyrrolidone hydrogel wound dressing containing zinc oxide nanoparticles promote wound healing in a rat model of excision injury

Developing and designing efficient wound dressings have gained increasing attention and shown beneficial results in improved wound healing effects. This study was conducted to improve wound healing properties and introduce a novel potential wound dressing. A novel hydrogel based on polyvinylpyrrolidone/poly acrylic acid containing Zinc oxide nanoparticles was prepared as an antibacterial wound dressing and examined in a rat excisional wound model. This hydrogel prepared by free radical polymerization using potassium persulfate (KPS) as an initiator, N, N-methylene bisacrylamide (MBA) as a cross-linker, poly acrylic acid (PAA) as a monomer in the presence of polyvinylpyrrolidone (PVP) and Zinc oxide nanoparticles (ZnO NPs). Analyses such as Scanning Electron Microscope (SEM), Fourier-transform infrared spectroscopy (FTIR), X-ray diffraction analysis (XRD), and Thermal gravimetric analysis (TGA) were used to study morphology structure. After choosing the optimal sample, in vivo characterization of excisional wound injury on a rat model was done. The healing rate and histological analysis were calculated and compared among the groups. The therapeutic potential of the PAA-PVP-ZnO-%2 was investigated in a rat model of excisional injury compared to the control group. Results showed that the polyacrylic acid/polyvinylpyrrolidone hydrogel wound dressing containing zinc oxide nanoparticles accelerated wound contraction, had antibacterial effects, and promoted wound healing compared to other groups.

In Situ Ultra-Small- and Small-Angle X-ray Scattering Study of ZnO Nanoparticle Formation and Growth through Chemical Bath Deposition in the Presence of Polyvinylpyrrolidone.

ZnO inverse opals combine the outstanding properties of the semiconductor ZnO with the high surface area of the open-porous framework, making them valuable photonic and catalysis support materials. One route to produce inverse opals is to mineralize the voids of close-packed polymer nanoparticle templates by chemical bath deposition (CBD) using a ZnO precursor solution, followed by template removal. To ensure synthesis control, the formation and growth of ZnO nanoparticles in a precursor solution containing the organic additive polyvinylpyrrolidone (PVP) was investigated by in situ ultra-small- and small-angle X-ray scattering (USAXS/SAXS). Before that, we studied the precursor solution by in-house SAXS at T = 25 °C, revealing the presence of a PVP network with semiflexible chain behavior. Heating the precursor solution to 58 °C or 63 °C initiates the formation of small ZnO nanoparticles that cluster together, as shown by complementary transmission electron microscopy images (TEM) taken after synthesis. The underlying kinetics of this process could be deciphered by quantitatively analyzing the USAXS/SAXS data considering the scattering contributions of particles, clusters, and the PVP network. A nearly quantitative description of both the nucleation and growth period could be achieved using the two-step Finke-Watzky model with slow, continuous nucleation followed by autocatalytic growth.

Perovskite CuO@BaSnO3 nanorods photocatalysts with promoted visible light ability for desulfurization of thiophene

BackgroundThe desulfurization of fuels is critical to upgrade their performance and to match the demands of sulfur standards MethodMesoporous p-n heterojunctions CuO/BaSnO3 nanorods were fabricated by the hydrothermal process in the presence of polyvinylpyrrolidone. The photocatalytic performance of the synthesized CuO/BaSnO3 nanorods at various CuO percentages compared with the pristine BaSnO3 was evaluated by desulfurising thiophene under visible light illumination Significant findingsXRD and HRTEM results verified the fabrication of perovskite BaSnO3 in cubic structure and CuO in the monoclinic phase, and TEM images of CuO/BaSnO3 exhibited nanorod-like morphology with a length of 100 nm and width of 10 nm decorated with CuO NPs (5 nm). After optimization, the experimental results showed that with a photocatalyst dosage of 2 g/L and CuO percentage of 15%, the maximal desulfurization rate of thiophene was around 100% within 60 min. The rate constant of 15% CuO/BaSnO3 photocatalyst was the maximum, and it was enhanced larger 3.36 times than that of the pristine BaSnO3 nanorods. The photocurrent intensity of 15% CuO/BaSnO3 photocatalyst was enhanced 9.2 times greater than that of pristine BaSnO3. The enhancement of the desulfurization rate illustrated that the creation of an internal electric field through the p-n heterojunction CuO/BaSnO3 system could facilitate the separation of photoinduced holes and electrons, improving the charge transport ability and hence promoting the photocatalytic performance. PL, transient photocurrent responses and electrochemical impedance results were determined to confirm our photocatalytic results. Cycling runs displayed that the obtained CuO/BaSnO3 photocatalyst still exhibited high photocatalytic ability and stability after five cycles. This work is anticipated to strengthen the design of effective and novel p-n heterojunctions photocatalysts for practical photocatalysis applications in terms of H2 production and detoxification of toxic organic compounds.

Gamma Radiation-Induced Synthesis and Characterization of Decahedron-Like Silver Nanostructure and Their Antimicrobial Application

AbstractIn the current study, a decahedron-like silver nanostructure (D-AgNs) was successfully created in an aqueous solution in the presence of Polyvinylpyrrolidone (PVP) as a capping agent using the gamma-radiolysis approach without the use of a reducing agent. The synthesized D-AgNs were characterized using various analytical tools such as UV–Vis. spectroscopy, SEM, XRD, HRTEM, EDX and FTIR. UV–Vis. absorption spectra showed considerable surface Plasmon resonance (SPR) bands at 350–600 nm, indicating that colloidal D-AgNs had been successfully synthesized. HRTEM image demonstrates well-dispersed uniformly decahedral shapes that are well separated from each other. The produced nanoparticles were effectively stabilized by PVP through interactions, confirmed by the FTIR anlaysis. The synthesis of D-AgNs using gamma radiation was accomplished, in addition its antimicrobial potential, antibiofilm activity, and the effect of UV rays were assessed. In addition, protein leakage assays and SEM imaging were employed to analyze the antimicrobial reaction’s mechanism. A wide variety of bacteria, including S. aureus, P. aeruginosa, and C. albicans, were deactivated by D-AgNs. In the antibiofilm assay, D-AgNs inhibited the biofilm formation of S. aureus (89.58%), E. coli (80.35%), and P. aureginosa (78.45%). After investigating the effect of D-AgNs on the growth curve of S. aureus, we concluded that D-AgNs affect the growth curve of S. aureus, and the curve was reduced to be 0.125. The formation of holes in the S. aureus cell membrane is explained by the fact that the amount of cellular protein released from the bacteria is directly proportional to the concentration of D-AgNs, which was determined to be 259.25 µg/ml at concentration equal to 1.0 mg/mL.

THE ACTIVATION OF ANIONIC DYE ADSORPTION AFTER UV IRRADIATION OF INDIVIDUAL AND BINARY XEROGELS OF ALUMINUM AND ZIRCONIUM OXIDES

Mesoporous xerogels of hydrated individual and binary oxides of aluminum (A) and zirconium (Z) were obtained by hydrolysis sol-gel method after drying at 180 °C of a hydrogel synthesized from aluminum nitrate and zirconium oxychloride in the presence of polyvinylpyrrolidone. The samples were examined by IR spectroscopy, SEM, XRD, BET/BJH. It was found that the xerogels are X-ray amorphous. The particles have a hierarchical structure, the specific surface in a series (number and mol.%) of samples A (1) < 65AZ (2) < 35AZ (3) < Z (4) increases exponentially from 21 to 298 m2/g. The pore diameter is 4-6 nm. Photoactive aluminum oxohydroxide (δAlOOH = 1070 cm-1) is registered only in samples 1 and 2. Adsorption from an aqueous solution using the example of anionic dye methyl orange was determined by spectrophotometer for long-time (24 h) and dynamic (10 min) regime. In both cases, Gibbs adsorption of Гm (μmol/g) increases in a number of samples 1 < 2 < 3 < 4. The value of ГS (μmol/m2) in the same series decreases sharply. Therefore, the adsorption centers of Al+3 and Zr+4 have different activity. It is shown that only in the case of AZ samples a photo activated adsorption rise after UV irradiation of sorbents with a mercury lamp for 10 min of duration. Kinetic adsorption curves for samples without and with UV treatment correspond to the pseudo-second-order equation with Langmuir-type two-fold adsorption model. The parameters of this equation Гmax (monolayer capacity) and W0 (initial adsorption rate) increase in a series of non-irradiated samples 1 < 2 < 3 < 4. The effect of UV activation, as the ratio of Гmax and W0 after and before irradiation, augments in the sequence Z < A < 35AZ < 65AZ (for 65AZ sample the growth of Гmax and W0 is 2.4 and 1.8 times, while the adsorption rate constant k2 decreases tenfold). Comparison of adsorption after 24 h with Гmax showed a linear decrease in the ratio Г24/Гmax for unirradiated sorbents A (2.9) > 65AZ (2.2) > 35AZ (1.6) > I(1.0). This result is explained by adsorption-induced deformation of the xerogel framework, which is greatest in Al2O3 and absent in ZrO2. For citation: Vakhrushev N.E., MIkhalenko I.I., Podzorova L.I. The activation of anionic dye adsorption after UV irradiation of individual and binary xerogels of aluminum and zirconium oxides. ChemChemTech [Izv. Vyssh. Uchebn. Zaved. Khim. Khim. Tekhnol.]. 2023. V. 66. N 6. P. 61-68. DOI: 10.6060/ivkkt.20236606.6744.

Green Nanoformulations of Polyvinylpyrrolidone-Capped Metal Nanoparticles: A Study at the Hybrid Interface with Biomimetic Cell Membranes and In Vitro Cell Models.

Noble metal nanoparticles (NP) with intrinsic antiangiogenic, antibacterial, and anti-inflammatory properties have great potential as potent chemotherapeutics, due to their unique features, including plasmonic properties for application in photothermal therapy, and their capability to slow down the migration/invasion speed of cancer cells and then suppress metastasis. In this work, gold (Au), silver (Ag), and palladium (Pd) NP were synthesized by a green redox chemistry method with the reduction of the metal salt precursor with glucose in the presence of polyvinylpyrrolidone (PVP) as stabilizing and capping agent. The physicochemical properties of the PVP-capped NP were investigated by UV-visible (UV-vis) and attenuated total reflection Fourier transform infrared (ATR-FTIR) spectroscopies, dynamic light scattering (DLS), and atomic force microscopy (AFM), to scrutinize the optical features and the interface between the metal surface and the capping polymer, the hydrodynamic size, and the morphology, respectively. Biophysical studies with model cell membranes were carried out by using laser scanning confocal microscopy (LSM) with fluorescence recovery after photobleaching (FRAP) and fluorescence resonance energy transfer (FRET) techniques. To this purpose, artificial cell membranes of supported lipid bilayers (SLBs) made with 1-palmitoyl-2-oleoyl-sn-glycerol-3-phosphocholine (POPC) dye-labeled with 7-nitro-2-1,3-benzoxadiazol-4-yl (NBD, FRET donor) and/or lissamine rhodamine B sulfonyl (Rh, FRET acceptor) were prepared. Proof-of-work in vitro cellular experiments were carried out with prostate cancer cells (PC-3 line) in terms of cytotoxicity, cell migration (wound scratch assay), NP cellular uptake, and cytoskeleton actin perturbation.

Controlling the aspect ratio of silver nanowires in the modified polyol process

Metal nanowire-based conducting networks, primarily based on silver nanowires (Ag NWs), show promise for flexible transparent conducting electrodes. The synthesis of high aspect ratio Ag NWs is the key to accomplishing good optoelectronic performance. Among the various synthesis routes available, the one-pot polyol method is widely used. It is based on the reduction of silver nitrate (AgNO3) by a polyol, typically ethylene glycol, in the presence of polyvinylpyrrolidone (PVP) and ferric chloride. The present work provides a systematic study of the role of PVP to AgNO3 weight ratio on the physical dimensions (length, diameter, and aspect ratio) of the Ag NWs and the role of NW concentration and spin coating speed on the optoelectronic properties (transparency and conductivity) of the NW-based network.

Comparative study of four innovative earth-friendly platforms for rapid analysis of daclatasvir dihydrochloride: Application on different matrices

BackgroundDaclatasvir dihydrochloride has important roles not only in the management of COVID-19 pandemic symptoms but also in the treatment of chronic hepatitis C infection.ObjectiveThe current research presents four novel and simple platforms including silver-nanoparticles spectrophotometric technique and three electrochemical conductometric ones for daclatasvir analysis in its tablet, biological fluids, and dissolution media.MethodsThe spectrophotometric platform involved the synthesis of silvernanoparticles through a redox reaction between the reducing agent (daclatasvir) and the oxidizing agent (silver nitrate) in presence of polyvinylpyrrolidone as a stabilizing agent. The produced silver-nanoparticles have an intense surface plasmon resonance peak at 421 nm where the measured absorbance values were utilized for quantitative spectrophotometric determination of daclatasvir. While the electrochemical conductometric platforms involved the reaction of daclatasvir with three different precipitating reagents (silver nitrate, phosphomolybdic acid, and ammonium reineckate) to form ion associates between these reagents and daclatasvir in the aqueous system.ResultsAll proposed platforms were validated in line with recommendations of the international conference on harmonization producing satisfactory outcomes within the agreed boundaries.ConclusionThe proposed platforms are green alternatives for routine rapid assay of daclatasvir at the cheapest cost because their results were observed to be nearly similar to those of the reported platform. Moreover, the suggested spectrophotometric platform’s sensitivity can be employed for investigating daclatasvir bioequivalence.

Earth-friendly-assessed silver-nanoparticles spectrophotometric method for rapid and sensitive analysis of Molnupiravir, an FDA-approved candidate for COVID-19: application on pharmaceutical formulation and dissolution test

Molnupiravir is the first oral direct-acting antiviral prodrug recently approved for the COVID-19 pandemic. Here and for the first time, we present a novel, sensitive, robust, and simple silver-nanoparticles spectrophotometric technique for molnupiravir analysis in its capsules and dissolution media. This spectrophotometric technique involved silver-nanoparticles synthesis through a redox reaction between the reducing agent (molnupiravir) and the oxidizing agent (silver nitrate) in presence of polyvinylpyrrolidone as a stabilizing agent. The produced silver-nanoparticles have an intense surface plasmon resonance peak at 416 nm where the measured absorbance values were utilized for the quantitative analysis of molnupiravir. The produced silver-nanoparticles were recognized by using the transmission electron microscope. Under optimal conditions, a good linear rapport was accomplished between molnupiravir concentrations and the corresponding absorbance values in a range of (100–2000) ng/mL with a detection limit of 30 ng/mL. Greenness assessment was implemented using eco-scale scoring and GAPI disclosing the excellent greenness of the suggested technique. The suggested silver-nanoparticles technique was authenticated according to recommendations of the ICH and statistically assessed with the reported liquid chromatographic method without significant differences regarding accuracy or precision. Accordingly, the suggested technique is deemed a green and cheap alternative for assaying molnupiravir due to its reliance primarily on water. Furthermore, the suggested technique’s high sensitivity can be employed for investigating molnupiravir bioequivalence in future studies.Graphical

Polymer photosensitizing systems containing porphyrins, dinitrosyl iron complexes, and sodium alginate in the generation of singlet oxygen

The activity of photosensitizing systems based on water-soluble photoditazine (PDZ) and hydrophobic fluorinated tetraphenylporphyrin (TPPF20) solubilized polyvinylpyrrolidone (PVP) (in the case PDZ) and pluronic F127 (in the case TPPF20) was studied in a model reaction of tryptophan (Trp) photooxidation. We also studied the effect of dinitrosyl iron complex (DNIC) and sodium alginate (SA) polysaccharide on the photosensitizing activity of both PDZ in the presence of PVP and TPPF20 solubilized with pluronic F127 in a model reaction of Trp photooxidation. It was shown that TPPF20 solubilized with pluronic F127 exhibits high photocatalytic activity in the presence of both DNIC and SA. It was also shown that PVP is able to prevent the damaging effect exerted by active NO radicals produced during the photodecomposition of DNIC on PDZ molecules. Moreover, it was demonstrated that SA does not influence the photocatalytic activity of PDZ in the presence and absence of PVP. Using the dynamic light scattering method, it was found that SA macromolecules in the presence of PVP are capable of self-association, which, due to the ‘excluded volume’ effect, can cause a slight increase in the rate of photocatalytic reaction. The effectiveness of using PDZ in combination with PVP in the presence of SA and DNIC as a photosensitizer in antimicrobial photodynamic therapy was studied via in vivo experiments on a model of a full-layer planar wound in laboratory rats. Morphological studies have shown that under photodynamic action on wounds, the use of these systems (compared to photoexcitation of an aqueous solution of the initial PDZ) stimulates the transition of the inflammatory phase to the reparative (proliferative) phase. In addition, the process of cleansing wounds from microflora and devitalized tissues is accelerated, the disturbed microcirculation is restored, the proliferation of fibroblasts and blood vessels, and collagen synthesis are accelerated. It is suggested that the PDZ-PVP-SA-DNIC systems can be used in PDT procedures for the treatment of inflammatory diseases of the skin and soft tissues.

Synthesis of Bi2O3 NPs with polyethylene glycol and investigation of photodegradation of phenazopyridine in aqueous solution

The synthesis of Bi2O3 by a simple chemical route in the presence of polyvinylpyrrolidone (PP) as surfactant was studied. The sample was characterized by XRD, FTIR, and DRS techniques. Its pHpzc was estimated about 9.5. Crystallite size of the as-synthesized sample was estimated about 45 and 14 nm by the Scherrer and Williamson-Hall models, respectively. Band gap energy was estimated about 2.98 eV using the adsorption edge wavelength, while by using the Kubelka-Munk theory Eg-values of 3.21, 3.13, 3.27, and 3.24 eV were obtained for n-values of 2, 1/2, 3/2, and 3, respectively. The photocatalytic performance of the Bi2O3 NPs was evaluated against phenazopyridine as a model pollutant. Experimental optimized parameters were as adsorbent dosage = 0.7 g/L, contact time = 60 min, pH 7, illumination time: 60 min, CPP: 20 ppm. The photocatalytic kinetics model obeyed the pseudo-first order kinetic model.

Oriented attachment of carbon/cobalt-cobalt oxide nanotubes on manganese-doped carbon nanofibers for flexible symmetric supercapacitors

Electrodes for flexible supercapacitors were fabricated from manganese-doped carbon nanofibers (Mn-CNF) decorated with carbon-coated Co-CoOx (C/Co-CoOx) nanotubes. The Mn-doped polyacrylonitrile (PAN)–2-methylimidazole (2MI) solution was electrospun using optimized Mn concentrations and ZIF-67 was then surface loaded by wet impregnation with added polyvinylpyrrolidone (PVP). These ZIF-67 loaded Mn-fibers, when annealed, resulted in carbon-coated C/Co-CoOx nanotubes on the Mn-CNF surface. In the presence of PVP, ZIF-67 oriented attachment occurs, forming evenly dispersed CoOx particles even after high temperature annealing. XRD spectra exhibit the formation of metallic Co nanoparticles (NPs), whereas Raman spectra and XPS indicate Co particle oxidation. A carbon coating limits the oxidation of Co; thus, the particles are called C/Co-CoOx. A symmetric supercapacitor cell prepared using the CNFs decorated with C/Co-CoOx using an aqueous electrolyte has a capacitance of 1263 mF⋅cm−2 at a current density of 0.25 mA⋅cm−2 and a wide potential window of 1.4 V for the optimal case. Long-term cycling showed 110 % capacitance retention after 10,000 cycles. Moreover, bending tests and powering LEDs demonstrated the flexibility and improved charge storage of the prepared nanofiber electrodes.

A Facile Two-Step PVP-Assisted Deposition of Co-Activated Nanosized Nickel Hydroxide Directly on a Substrate for Large-Scale Production of Supercapacitor Electrodes

The self-decomposition reaction of the nickel ammonia complex was used for the nickel hydroxide formation on the nickel foam with further modification in several ways. The addition of polyvinyl pyrrolidone (PVP) and the electrochemical or chemical activation with cobalt hydroxide was used to modify the formation method. In all cases, structures with Ni(OH)2 nanoflakes were formed. It was found that the flower-like particles of Co(OH)2 were precipitated during chemical activation among the nanoflakes. It was shown that the presence of PVP during the nickel ammonia complex decomposition suppressed the highly branched particles. The absence of the highly branched particles increased the capacitive properties of the formed electrode at high current densities. The highest capacitance in 1408 F/g at 1 A/g was shown for the sample precipitated with the PVP presence and the further chemical activation by cobalt.