Optimization of ZnO Nanorods Growth on Polyetheresulfone Electrospun Mats to Promote Antibacterial Properties

Zinc oxide (ZnO) nanorods grown by chemical bath deposition (CBD) on the surface of polyetheresulfone (PES) electrospun fibers confer antimicrobial properties to the obtained hybrid inorganic–polymeric PES/ZnO mats. In particular, a decrement of bacteria colony forming units (CFU) is observed for both negative (Escherichia coli) and positive (Staphylococcus aureus and Staphylococcus epidermidis) Grams. Since antimicrobial action is strictly related to the quantity of ZnO present on surface, a CBD process optimization is performed to achieve the best results in terms of coverage uniformity and reproducibility. Scanning electron microscopy (SEM) and X-ray photoelectron spectroscopy (XPS) provide morphological and compositional analysis of PES/ZnO mats while thermogravimetric analysis (TGA) is useful to assess the best process conditions to guarantee the higher amount of ZnO with respect to PES scaffold. Biocidal action is associated to Zn2+ ion leaching in solution, easily indicated by UV–Vis measurement of metallation of free porphyrin layers deposited on glass.

Download Full-text

Silver-decorated gel-shell nanobeads: physicochemical characterization and evaluation of antibacterial properties

Beilstein Journal of Nanotechnology ◽

10.3762/bjnano.11.49 ◽

2020 ◽

Vol 11 ◽

pp. 620-630 ◽

Cited By ~ 1

Author(s):

Marta Bartel ◽

Katarzyna Markowska ◽

Marcin Strawski ◽

Krystyna Wolska ◽

Maciej Mazur

Keyword(s):

Silver Nanoparticles ◽

Sodium Borohydride ◽

Staphylococcus Epidermidis ◽

Photoelectron Spectroscopy ◽

Antibacterial Properties ◽

Physicochemical Characterization ◽

Silver Ions ◽

X Ray ◽

Gel Layer ◽

Lower Oxidation

We report on the synthesis of composite nanobeads with antibacterial properties. The particles consist of polystyrene cores that are surrounded by sulfonic gel shells with embedded silver nanoparticles. The nanocomposite beads are prepared by sulfonation of polystyrene particles followed by accumulation of silver ions in the shell layer and subsequent reduction with sodium borohydride. The resulting material has been characterized by electron microscopy, vibrational and X-ray photoelectron spectroscopy and several other experimental techniques. It was shown that sodium borohydride reduces silver ions embedded in the gel layer producing silver nanoparticles but also transforms a fraction of sulfonic groups in the polymer to moieties with sulfur in a lower oxidation state, likely thiols. It is hypothesized that the generated thiol groups are anchoring the nanoparticles in the gel shell of the nanobeads stabilizing the whole structure. The silver-decorated nanobeads appear to be a promising material with considerable antimicrobial activity and were tested against Escherichia coli, Pseudomonas aeruginosa, Staphylococcus aureus and Staphylococcus epidermidis. The determined minimum inhibitory (MIC) and minimum biofilm inhibitory (MBIC) concentrations are comparable to those of non-incorporated silver nanoparticles.

Download Full-text

Evaluation of the Antimicrobial Protection of Pharmaceutical Kaolin and Talc Modified with Copper and Zinc

Materials ◽

10.3390/ma14051173 ◽

2021 ◽

Vol 14 (5) ◽

pp. 1173

Author(s):

Fotini Martsouka ◽

Konstantinos Papagiannopoulos ◽

Sophia Hatziantoniou ◽

Martin Barlog ◽

Giorgos Lagiopoulos ◽

...

Keyword(s):

Cation Exchange ◽

Photoelectron Spectroscopy ◽

Antimicrobial Properties ◽

Exchange Capacity ◽

Elevated Concentration ◽

Chemical Mapping ◽

Exchange Method ◽

X Ray ◽

Copper And Zinc ◽

Antimicrobial Protection

Six pharmaceutical pastes were prepared using chemically modified kaolin and talc powders. Tests were conducted to determine their structural and chemical characteristics as well as their antimicrobial protection, thus rendering them suitable for cosmetic and pharmaceutical uses. Kaolin and talc were treated chemically via the cation exchange method to load the clay particles with copper and zinc ions, two cations well known for their antimicrobial properties. Mineralogical analyses were conducted by using X-ray diffraction (XRD) before and after the modification, confirming the mineralogical purity of the samples. Scanning electron microscopy was also used in conjunction with energy dispersed spectroscopy (SEM-EDS) to obtain chemical mapping images, revealing the dispersion of the added metals upon the clay minerals surfaces. Moreover, chemical analysis has been performed (XRF) to validate the enrichment of the clays with each metal utilizing the cation exchange capacity. All modified samples showed the expected elevated concentration in copper or zinc in comparison to their unmodified versions. From the X-ray photoelectron spectroscopy (XPS), the chemical state of the samples’ surfaces was investigated, revealing the presence of salt compounds and indicating the oxidation state of adsorbed metals. Finally, the resistance of pastes in microbial growth when challenged with bacteria, molds, and yeasts was assessed. The evaluation is based on the European Pharmacopeia (EP) criteria.

Download Full-text

Lactoferrin/Calcium Phosphate-Modified Porous Ti by Biomimetic Mineralization: Effective Infection Prevention and Excellent Osteoinduction

Materials ◽

10.3390/ma14040992 ◽

2021 ◽

Vol 14 (4) ◽

pp. 992

Author(s):

Song Chen ◽

Yuanli He ◽

Linna Zhong ◽

Wenjia Xie ◽

Yiyuan Xue ◽

...

Keyword(s):

Calcium Phosphate ◽

Photoelectron Spectroscopy ◽

Antibacterial Properties ◽

Biomimetic Mineralization ◽

Matrix Mineralization ◽

X Ray ◽

Porous Ti ◽

Potential Applications ◽

Modification Of Titanium

The surface modification of titanium (Ti) can enhance the osseointegration and antibacterial properties of implants. In this study, we modified porous Ti discs with calcium phosphate (CaP) and different concentrations of Lactoferrin (LF) by biomimetic mineralization and examined their antibacterial effects and osteogenic bioactivity. Firstly, scanning electron microscopy (SEM), the fluorescent tracing method, X-ray photoelectron spectroscopy (XPS), Fourier transform infrared spectroscopy (FTIR), energy dispersive X-ray spectroscopy (EDX), X-ray diffraction (XRD), and the releasing kinetics of LF were utilized to characterize the modified Ti surface. Then, the antibacterial properties against S. sanguis and S. aureus were investigated. Finally, in vitro cytological examination was performed, including evaluations of cell adhesion, cell differentiation, extracellular matrix mineralization, and cytotoxicity. The results showed that the porous Ti discs were successfully modified with CaP and LF, and that the LF-M group (200 μg/mL LF in simulated body fluid) could mildly release LF under control. Further, the LF-M group could effectively inhibit the adhesion and proliferation of S. sanguis and S. aureus and enhance the osteogenic differentiation in vitro with a good biocompatibility. Consequently, LF-M-modified Ti may have potential applications in the field of dental implants to promote osseointegration and prevent the occurrence of peri-implantitis.

Download Full-text

Oxidative Desulfurization of Tire Pyrolysis Oil over Molybdenum Heteropolyacid Loaded Mesoporous Catalysts

Reactions ◽

10.3390/reactions2040029 ◽

2021 ◽

Vol 2 (4) ◽

pp. 457-472

Author(s):

Jasmine Kaur ◽

Sundaramurthy Vedachalam ◽

Philip Boahene ◽

Ajay K. Dalai

Keyword(s):

Sulfur Content ◽

Photoelectron Spectroscopy ◽

Supported Catalysts ◽

Surface Acidity ◽

Oxidative Desulfurization ◽

Acid Catalyst ◽

Acid Sites ◽

Process Conditions ◽

Pyrolysis Oil ◽

X Ray

Pyrolysis oil derived from waste tires consists of sulfur content in the range of 7000 to 9000 ppm. For use in diesel engines, its sulfur content must be lowered to 10 to 15 ppm. Though conventional hydrodesulfurization is suitable for the removal of sulfur from tire pyrolysis oil, its high cost provides an avenue for alternative desulfurization technologies to be explored. In this study, oxidative desulfurization (ODS), a low-cost technology, was explored for the desulfurization of tire pyrolysis oil. Two categories of titanium-incorporated mesoporous supports with 20 wt% loaded heteropoly molybdic acid catalyst (HPMo/Ti-Al2O3 and HPMo/Ti-TUD-1) were developed and tested for ODS of tire pyrolysis oil at mild process conditions. Catalysts were characterized by X-ray diffraction, BET-N2 physisorption, and X-ray photoelectron spectroscopy (XPS). The incorporation of Ti into Al2O3 and TUD-1 frameworks was confirmed by XPS. The surface acidity of catalysts was studied by the temperature-programmed desorption of NH3 and pyridine FTIR analyses. HPMo/Ti-Al2O3 and HPMo/Ti-TUD-1 catalysts contained both Lewis and Brønsted acid sites. The presence of titanium in catalysts was found to promote the ODS activity of phosphomolybdic acid. The Ti-TUD-1-supported catalysts performed better than the Ti-Al2O3-supported catalysts for the ODS of tire pyrolysis oil. Hydrogen peroxide and cumene peroxide were found to be better oxidants than tert-butyl hydroperoxide for oxidizing sulfur compounds of tire pyrolysis oil. Process parameter optimization by the design of experiments was conducted with an optimal catalyst along with the catalyst regeneration study. An ANOVA statistical analysis demonstrated that the oxidant/sulfur and catalyst/oil ratios were more significant than the reaction temperature for the ODS of tire pyrolysis oil. It followed the pseudo-first-order kinetics over HPMo/Ti-TUD-1.

Download Full-text

Origin of the surface recombination centers in ZnO nanorods arrays by X-ray photoelectron spectroscopy

Applied Surface Science ◽

10.1016/j.apsusc.2009.12.160 ◽

2010 ◽

Vol 256 (11) ◽

pp. 3592-3597 ◽

Cited By ~ 79

Author(s):

L.L. Yang ◽

Q.X. Zhao ◽

M. Willander ◽

X.J. Liu ◽

M. Fahlman ◽

...

Keyword(s):

Photoelectron Spectroscopy ◽

Zno Nanorods ◽

Surface Recombination ◽

X Ray ◽

Recombination Centers

Download Full-text

High-Performance Flexible Ultraviolet Photodetectors with Ni/Cu-Codoped ZnO Nanorods Grown on PET Substrates

Nanomaterials ◽

10.3390/nano9081067 ◽

2019 ◽

Vol 9 (8) ◽

pp. 1067 ◽

Cited By ~ 8

Author(s):

Hafiz Muhammad Salman Ajmal ◽

Fasihullah Khan ◽

Noor Ul Huda ◽

Sunjung Lee ◽

Kiyun Nam ◽

...

Keyword(s):

Photoelectron Spectroscopy ◽

High Performance ◽

Electronic Device ◽

Deep Level ◽

Zno Nanorods ◽

Ultra Violet ◽

Device Fabrication ◽

Electrode Structure ◽

Large Area ◽

X Ray

As a developing technology for flexible electronic device fabrication, ultra-violet (UV) photodetectors (PDs) based on a ZnO nanostructure are an effective approach for large-area integration of sensors on nonconventional substrates, such as plastic or paper. However, photoconductive ZnO nanorods grown on flexible substrates have slow responses or recovery as well as low spectral responsivity R because of the native defects and inferior crystallinity of hydrothermally grown ZnO nanorods at low temperatures. In this study, ZnO nanorod crystallites are doped with Cu or Ni/Cu when grown on polyethylene terephthalate (PET) substrates in an attempt to improve the performance of flexible PDs. The doping with Ni/Cu or Cu not only improves the crystalline quality but also significantly suppresses the density of deep-level emission defects in as-grown ZnO nanorods, as demonstrated by X-ray diffraction and photoluminescence. Furthermore, the X-ray photoelectron spectroscopy analysis shows that doping with the transition metals significantly increases the oxygen bonding with metal ions with enhanced O/Zn stoichiometry in as-grown nanorods. The fabricated flexible PD devices based on an interdigitated electrode structure demonstrates a very high R of ~123 A/W, a high on-off current ratio of ~130, and a significant improvement in transient response speed exhibiting rise and fall time of ~8 and ~3 s, respectively, by using the ZnO nanorods codoped by Ni/Cu.

Download Full-text

Vis-Responsive Copper-Modified Titania for Decomposition of Organic Compounds and Microorganisms

Catalysts ◽

10.3390/catal10101194 ◽

2020 ◽

Vol 10 (10) ◽

pp. 1194

Author(s):

Maya Endo-Kimura ◽

Bariş Karabiyik ◽

Kunlei Wang ◽

Zhishun Wei ◽

Bunsho Ohtani ◽

...

Keyword(s):

Visible Light ◽

Photoelectron Spectroscopy ◽

Water Oxidation ◽

Diffuse Reflectance Spectroscopy ◽

Antimicrobial Properties ◽

Localized Surface Plasmon ◽

Intrinsic Activity ◽

Ambient Conditions ◽

Copper Species ◽

X Ray

Seven commercial titania (titanium(IV) oxide; TiO2) powders with different structural properties and crystalline compositions (anatase/rutile) were modified with copper by two variants of a photodeposition method, i.e., methanol dehydrogenation and water oxidation. The samples were characterized by diffuse reflectance spectroscopy (DRS), X-ray powder diffraction (XRD), scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDS) and X-ray photoelectron spectroscopy (XPS). Although zero-valent copper was deposited on the surface of titania, oxidized forms of copper, post-formed in ambient conditions, were also detected in dried samples. All samples could absorb visible light (vis), due to localized surface plasmon resonance (LSPR) of zero-valent copper and by other copper species, including Cu2O, CuO and CuxO (x:1-2). The photocatalytic activities of samples were investigated under both ultraviolet (UV) and visible light irradiation (>450 nm) for oxidative decomposition of acetic acid. It was found that titania modification with copper significantly enhanced the photocatalytic activity, especially for anatase samples. The prolonged irradiation (from 1 to 5 h) during samples’ preparation resulted in aggregation of copper deposits, thus being detrimental for vis activity. It is proposed that oxidized forms of copper are more active under vis irradiation than plasmonic one. Antimicrobial properties against bacteria (Escherichia coli) and fungi (Aspergillus niger) under vis irradiation and in the dark confirmed that Cu/TiO2 exhibits a high antibacterial effect, mainly due to the intrinsic activity of copper species.

Download Full-text

Fabrication of Hybrid Catalyst ZnO Nanorod/α-Fe2O3 Composites for Hydrogen Evolution Reaction

Crystals ◽

10.3390/cryst10050356 ◽

2020 ◽

Vol 10 (5) ◽

pp. 356

Author(s):

Kasimayan Uma ◽

Elavarasan Muniranthinam ◽

Siewhui Chong ◽

Thomas C.-K Yang ◽

Ja-Hon Lin

Keyword(s):

Hydrogen Evolution ◽

Hydrogen Evolution Reaction ◽

Photoelectron Spectroscopy ◽

Electrochemical Impedance ◽

Nickel Foam ◽

Zno Nanorods ◽

Synergetic Effect ◽

Zno Nanorod ◽

Fe2o3 Nanoparticles ◽

X Ray

This report presents the synthesis of ZnO nanorod/α-Fe2O3 composites by the hydrothermal method with different weight percentages of α-Fe2O3 nanoparticles. The as-synthesized nanorod composites were characterized by different techniques, such as X-ray diffraction (XRD), Fourier transform-infrared (FT-IR), field emission scanning electron microscopy (FE-SEM), electrochemical impedance spectroscopy (EIS), and X-ray photoelectron spectroscopy (XPS). From our results, it was found that the ZnO/α-Fe2O3 (3 wt%) nanorod composites exhibit a higher hydrogen evolution reaction (HER) activity when compared to other composites. The synergetic effect between ZnO and (3 wt%) of α-Fe2O3 nanocomposites resulted in a low onset potential of −125 mV, which can effectively produce more H2 than pure ZnO. The H2 production rate over the composite of ZnO/α-Fe2O3 (3 wt%) clearly shows a significant improvement in the photocatalytic activity in the heterojunction of the ZnO nanorods and α-Fe2O3 nanoparticles on nickel foam.

Download Full-text

One-Step Reinforcement and Deacidification of Paper Documents: Application of Lewis Base—Chitosan Nanoparticle Coatings and Analytical Characterization

Coatings ◽

10.3390/coatings10121226 ◽

2020 ◽

Vol 10 (12) ◽

pp. 1226

Author(s):

Zhihui Jia ◽

Chun Yang ◽

Fangnan Zhao ◽

Xiaolian Chao ◽

Yuhu Li ◽

...

Keyword(s):

Photoelectron Spectroscopy ◽

Chitosan Nanoparticles ◽

Antibacterial Properties ◽

Interaction Mechanism ◽

Accelerated Aging ◽

Natural Aging ◽

Lewis Base ◽

X Ray ◽

Chitosan Nanoparticle ◽

One Step

To delay acidification and deterioration during natural aging, deacidification and reinforcement of paper manuscripts have been the most important technologies to prolong the life of objects. Herein, a novel approach for the conservation of paper manuscripts is proposed using chitosan nanoparticles as Lewis base that leads to both deacidification and strengthening of paper in one-step. Chitosan nanoparticles were prepared through physical ball grinding method and characterized via scanning electron microscopy (SEM), X-ray diffraction (XRD), laser particle size analyzer (LPSA), Fourier transform infrared spectroscopy (FTIR), and atomic force microscope (AFM). To evaluate the resistance of chitosan nanoparticle coating, the mechanical properties of paper after artificial aging were evaluated using dry heat and hygrothermal accelerated aging methods. The SEM, EDX, and X-ray Photoelectron Spectroscopy (XPS) were used to analyze the interaction mechanism between chitosan and Shuxuan paper. The results show that the coated paper had superior durability with respect to pH, tensile strength, and folding endurance. There was a presence of protonated amines in the form of ammonium salts due to ionic bindings with free H+ in the acidified paper, and the remaining –NH2 could be used as a base reserve. Finally, the resulting coated papers displayed good antibacterial properties.

Download Full-text

Fabrication of cotton fabrics with durable antibacterial activities finishing by Ag nanoparticles

Textile Research Journal ◽

10.1177/0040517518758002 ◽

2018 ◽

Vol 89 (5) ◽

pp. 867-880 ◽

Cited By ~ 18

Author(s):

Yunping Wu ◽

Yan Yang ◽

Zhijie Zhang ◽

Zhihua Wang ◽

Yanbao Zhao ◽

...

Keyword(s):

Photoelectron Spectroscopy ◽

Inductively Coupled Plasma ◽

Antibacterial Properties ◽

Antimicrobial Activities ◽

Cotton Fabrics ◽

Synthesis Process ◽

Ag Nps ◽

X Ray ◽

E Coli ◽

Fabric Surface

In this paper, we propose a facile and mild route to prepare size-tunable silver nanoparticles (Ag NPs) and their finishing application on fabrication of antibacterial cotton fabrics. The as-prepared Ag NPs, with an average particles size of 2.3 nm, show the minimal inhibitory concentration of 7.8 µg/mL and the minimum bactericidal concentration of 15.6 µg/mL, respectively. In this study, sodium citrate served as a stabilizing agent to prevent Ag NP agglomeration in the synthesis process, and citric acid acted as a binder to fix Ag NPs on the cotton fabrics through chemical bonds in the finishing process. The results of Fourier transform infrared spectroscopy, ultraviolet-visible spectroscopy (UV-vis), X-ray diffraction, X-ray photoelectron spectroscopy, scanning electron microscopy, and energy-dispersive X-ray spectroscopy demonstrate that Ag NPs have been fixed and well dispersed on the cotton fabric surface. Ag contents in the hybrid fabrics were measured by the techniques of inductively coupled plasma atomic emission spectroscopy and UV-vis, and the antibacterial properties of hybrid fabrics were tested by the shake flask and agar diffusion plate method. It is found that the Ag NP coated cotton fabrics exhibit excellent antimicrobial activities against both the Gram-negative bacterium of Escherichia coli (E. coli) and the Gram-positive bacterium of Staphylococcus aureus ( S. aureus). The percentages of reduction bacteria remain at 91.8% and 98.7% for S. aureus and E. coli, respectively, even after 50 cycles of consecutive laundering, which indicates that the antibiotic performance of the as-fabricated hybrid fabrics is also durable.

Download Full-text