Physicochemical Properties of Advanced Nanostructured Materials for Dental Microimplant Coatings

An important aspect of orthodontic microimplants is represented by biocompatibility and avoidance of infection development at living tissue surrounding it. Therefore, nanotechnology has the ability to improve this issue by coating microimplants with metal oxides type nanomaterials possessing antimicrobial effect. Some features of advanced nanostructured materials used as implant coatings, such as composition, structure, specific surface area, porosity, shape and size are factors that make them suitable as antimicrobial agents. The present work deals with the structural and morphological studies of ZnO and TiO2 nanoparticles used to combat oral diseases. Coating microimplants with nanosized titanium oxide (TiO2) and zinc oxide (ZnO) may improve conditions for osseointegration in accordance with preventing oral infection. These metal oxides nanopowders were synthesized using sol-gel method. Structural and morphological investigation were carried out by XRD and FTIR spectra, SEM-EDX and TEM images respectively. XRD and FTIR analyses confirmed metal oxides crystallization and metal oxide bonds. SEM-EDX and TEM features confirmed elemental composition of these nanoparticles and their textural characteristics such as shape, size, porosity and agglomeration degree.

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Preparation and Characterization of Transparent Electrodes Based on CNT-s Doped Metal Oxides

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.324.133 ◽

2011 ◽

Vol 324 ◽

pp. 133-136

Author(s):

Madis Paalo ◽

Tanel Tätte ◽

Eugene Shulga ◽

Madis Lobjakas ◽

Aare Floren ◽

...

Keyword(s):

Metal Oxides ◽

Transition Metal Oxides ◽

Electrode Materials ◽

Sol Gel ◽

Physical Stability ◽

Chemical Vapor ◽

Transparent Electrode ◽

Electrical And Optical Properties ◽

Materials Used

In the present work, it is shown that carbon nanotube-doped transition metal oxides are potential candidates for use as ceramic transparent electrode materials. Used carbon nanotubes (CNT-s) are synthesized by using chemical vapor deposition (CVD) method. Electrodes in shape of fibers are obtained via inexpensive and low temperature sol-gel method. Due to extraordinary electrical and optical properties of CNT-s and good chemical and physical stability of metal oxide ceramics, resulting composites could be an interesting subject for industry.

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Antibacterial Additives in Epoxy Resin-Based Root Canal Sealers: A Focused Review

Dentistry Journal ◽

10.3390/dj7030072 ◽

2019 ◽

Vol 7 (3) ◽

pp. 72 ◽

Cited By ~ 5

Author(s):

Alexander Brezhnev ◽

Prasanna Neelakantan ◽

Ray Tanaka ◽

Sergey Brezhnev ◽

George Fokas ◽

...

Keyword(s):

Physicochemical Properties ◽

Epoxy Resin ◽

Root Canal ◽

Antimicrobial Agents ◽

Dental Materials ◽

Antimicrobial Effect ◽

Antifungal Drugs ◽

Root Canal System ◽

Materials Used ◽

Root Canal Sealers

Dental materials used in root canal treatment have undergone substantial improvements over the past decade. However, one area that still remains to be addressed is the ability of root canal fillings to effectively entomb, kill bacteria, and prevent the formation of a biofilm, all of which will prevent reinfection of the root canal system. Thus far, no published review has analysed the literature on antimicrobial additives to root canal sealers and their influence on physicochemical properties. The aim of this paper was to systematically review the current literature on antimicrobial additives in root canal sealers, their anti-fouling effects, and influence on physicochemical properties. A systematic search was performed in two databases (PubMed and Scopus) to identify studies that investigated the effect of antimicrobial additives in epoxy resin-based root canal sealers. The nature of additives, their antimicrobial effects, methods of antimicrobial testing are critically discussed. The effects on sealer properties have also been reviewed. A total of 31 research papers were reviewed in this work. A variety of antimicrobial agents have been evaluated as additives to epoxy resin-based sealers, including quaternary ammonium compounds, chlorhexidine, calcium hydroxide, iodoform, natural extracts, antibiotics, antifungal drugs, and antimicrobial agent-functionalised nanoparticles. Antimicrobial additives generally improved the antimicrobial effect of epoxy resin-based sealers mainly without deteriorating the physicochemical properties, which mostly remained in accordance with ISO and ANSI/ADA specifications.

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Effect of Small Molecular Organic Acids on the Structure and Catalytic Performance of Sol–Gel Prepared Cobalt Cerium Oxides towards Toluene Combustion

Catalysts ◽

10.3390/catal9050483 ◽

2019 ◽

Vol 9 (5) ◽

pp. 483 ◽

Cited By ~ 2

Author(s):

Jianmeng Chen ◽

Junhong Lin ◽

Jinghuan Chen ◽

Jiade Wang

Keyword(s):

Catalytic Activity ◽

Organic Acids ◽

Metal Oxides ◽

Sol Gel ◽

Catalytic Performance ◽

Time Activity ◽

Cerium Oxides ◽

Structure Morphology ◽

Long Time ◽

Composition Structure

Cobalt cerium oxide catalysts with small molecular organic acids (SOAs) as chelating agents were prepared via the sol–gel method and investigated for the complete oxidation of toluene. Four kinds of natural SOAs, i.e. malic acid (MA), citric acid (CA), glycolic acid (GA), and tartaric acid (TA), were selected. The effect of organic acids on the composition, structure, morphology and catalytic performance of metal oxides is discussed in details. The cobalt cerium oxides catalysts were characterized by various techniques, including TG–DSC, XRD, SEM–EDS, N2–adsorption and desorption, XPS, and H2–TPR analyses. The results show that the nature of organic acids influenced the hydrolysis, condensation and calcination processes, as well as strongly affected the textural and physicochemical properties of the metal oxides synthesized. The best catalytic activity was obtained with the CoCe–MA catalyst, and the toluene conversion reached 90% at 242 °C. This outstanding catalytic activity could be related to its textural, redox properties and unique surface compositions and oxidation states. In addition, the CoCe–MA catalyst also showed excellent stability in long–time activity test.

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A Brief Overview of Electrochromic Materials and Related Devices: A Nanostructured Materials Perspective

Nanomaterials ◽

10.3390/nano11092376 ◽

2021 ◽

Vol 11 (9) ◽

pp. 2376

Author(s):

Aleksei Viktorovich Shchegolkov ◽

Sung-Hwan Jang ◽

Alexander Viktorovich Shchegolkov ◽

Yuri Viktorovich Rodionov ◽

Anna Olegovna Sukhova ◽

...

Keyword(s):

Nanostructured Materials ◽

Sol Gel ◽

Smart Window ◽

Electrochromic Materials ◽

Smart Windows ◽

Advantages And Disadvantages ◽

Light Modulators ◽

Light Filters ◽

Modern Analysis ◽

Materials Used

Exactly 50 years ago, the first article on electrochromism was published. Today electrochromic materials are highly popular in various devices. Interest in nanostructured electrochromic and nanocomposite organic/inorganic nanostructured electrochromic materials has increased in the last decade. These materials can enhance the electrochemical and electrochromic properties of devices related to them. This article describes electrochromic materials, proposes their classification and systematization for organic inorganic and nanostructured electrochromic materials, identifies their advantages and shortcomings, analyzes current tendencies in the development of nanomaterials used in electrochromic coatings (films) and their practical use in various optical devices for protection from light radiation, in particular, their use as light filters and light modulators for optoelectronic devices, as well as methods for their preparation. The modern technologies of “Smart Windows”, which are based on chromogenic materials and liquid crystals, are analyzed, and their advantages and disadvantages are also given. Various types of chromogenic materials are presented, examples of which include photochromic, thermochromic and gasochromic materials, as well as the main physical effects affecting changes in their optical properties. Additionally, this study describes electrochromic technologies based on WO3 films prepared by different methods, such as electrochemical deposition, magnetron sputtering, spray pyrolysis, sol–gel, etc. An example of an electrochromic “Smart Window” based on WO3 is shown in the article. A modern analysis of electrochromic devices based on nanostructured materials used in various applications is presented. The paper discusses the causes of internal and external size effects in the process of modifying WO3 electrochromic films using nanomaterials, in particular, GO/rGO nanomaterials.

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Antimicrobial properties of actively purified secondary metabolites isolated from different marine organisms

Current Pharmaceutical Biotechnology ◽

10.2174/1389201021666200730144536 ◽

2020 ◽

Vol 21 ◽

Author(s):

Nilushi Indika Bamunu Arachchige ◽

Fazlurrahman Khan ◽

Young-Mog Kim

Keyword(s):

Secondary Metabolites ◽

Pathogenic Bacteria ◽

Antimicrobial Agents ◽

Bacterial Species ◽

Antimicrobial Properties ◽

Antimicrobial Effect ◽

Cost Effective ◽

Resistance Mechanisms ◽

Marine Organisms ◽

Antimicrobial Compounds

Background: The treatment of infection caused by pathogenic bacteria becomes one of the serious concerns globally. The failure in the treatment was found due to the exhibition of multiple resistance mechanisms against the antimicrobial agents. Emergence of resistant bacterial species has also been observed due to prolong treatment using conventional antibiotics. To combat these problems, several alternative strategies have been employed using biological and chemically synthesized compounds as antibacterial agents. Marine organisms considered as one of the potential sources for the isolation of bioactive compounds due to the easily available, cost-effective, and eco-friendly. Methods: The online search methodology was adapted for the collection of information related to the antimicrobial properties of marine-derived compounds. These compound has been isolated and purified by different purification techniques, and their structure also characterized. Furthermore, the antibacterial activities have been reported by using broth microdilution as well as disc diffusion assays. Results: The present review paper describes the antimicrobial effect of diverse secondary metabolites which are isolated and purified from the different marine organisms. The structural elucidation of each secondary metabolite has also been done in the present paper, which will help for the in silico designing of the novel and potent antimicrobial compounds. Conclusion: A thorough literature search has been made and summarizes the list of antimicrobial compounds that are isolated from both prokaryotic and eukaryotic marine organisms. The information obtained from the present paper will be helpful for the application of marine compounds as antimicrobial agents against different antibiotic-resistant human pathogenic bacteria.

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Evaluation of Antifungal Activity by Mixed Oxide Metallic Nanocomposite against Candida spp.

Processes ◽

10.3390/pr9050773 ◽

2021 ◽

Vol 9 (5) ◽

pp. 773

Author(s):

Ayodeji Precious Ayanwale ◽

Brenda Lizbeth Estrada-Capetillo ◽

Simón Yobanny Reyes-López

Keyword(s):

Antifungal Activity ◽

Antimicrobial Agents ◽

Mononuclear Cells ◽

Promising Result ◽

Sol Gel ◽

Group Analysis ◽

Candida Spp ◽

Human Mononuclear Cells ◽

Viability Study ◽

High Doses

High doses of antimicrobial agents are a huge threat due to the increasing number of pathogenic organisms that are becoming resistant to antimicrobial agents. This resistance has led to a search for alternatives. Therefore, this study presents the synthesis and characterization of ZrO2-Ag2O nanoparticles (NPs) by sol-gel. The NPs were analyzed by dynamic light scattering (DLS), UV-visible (UV-vis), Raman and scanning electron microscopy (SEM). The NPs were later evaluated for their antifungal effects against Candidaalbicans, Candida dubliniensis, Candida glabrata, and Candida tropicalis, using disc diffusion and microdilution methods, followed by the viability study. The DLS showed sizes for ZrO2 76 nm, Ag2O 50 nm, and ZrO2-Ag2O samples between 14 and 42 nm. UV-vis shows an absorption peak at 300 nm for ZrO2 and a broadband for Ag2O NPs. Raman spectra were consistent with factor group analysis predictions. SEM showed spherically shaped NPs. The antifungal activity result suggested that ZrO2-Ag2O NPs were effective against Candida spp. From the viability study, there was no significance difference in viability as a function of time and concentration on human mononuclear cells. This promising result can contribute toward the development of alternative therapies to treat fungal diseases in humans.

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Effect of Titanium Dioxide Nanoparticles on the Expression of Efflux Pump and Quorum-Sensing Genes in MDR Pseudomonas aeruginosa Isolates

Antibiotics ◽

10.3390/antibiotics10060625 ◽

2021 ◽

Vol 10 (6) ◽

pp. 625

Author(s):

Fatma Y. Ahmed ◽

Usama Farghaly Aly ◽

Rehab Mahmoud Abd El-Baky ◽

Nancy G. F. M. Waly

Keyword(s):

Titanium Dioxide ◽

Quorum Sensing ◽

Biofilm Formation ◽

Antimicrobial Agents ◽

Efflux Pump ◽

Titanium Dioxide Nanoparticles ◽

Sol Gel ◽

Efflux Pumps ◽

Antibiofilm Activity ◽

The Impact

Most of the infections caused by multi-drug resistant (MDR) P. aeruginosa strains are extremely difficult to be treated with conventional antibiotics. Biofilm formation and efflux pumps are recognized as the major antibiotic resistance mechanisms in MDR P. aeruginosa. Biofilm formation by P. aeruginosa depends mainly on the cell-to-cell communication quorum-sensing (QS) systems. Titanium dioxide nanoparticles (TDN) have been used as antimicrobial agents against several microorganisms but have not been reported as an anti-QS agent. This study aims to evaluate the impact of titanium dioxide nanoparticles (TDN) on QS and efflux pump genes expression in MDR P. aeruginosa isolates. The antimicrobial susceptibility of 25 P. aeruginosa isolates were performed by Kirby–Bauer disc diffusion. Titanium dioxide nanoparticles (TDN) were prepared by the sol gel method and characterized by different techniques (DLS, HR-TEM, XRD, and FTIR). The expression of efflux pumps in the MDR isolates was detected by the determination of MICs of different antibiotics in the presence and absence of carbonyl cyanide m-chlorophenylhydrazone (CCCP). Biofilm formation and the antibiofilm activity of TDN were determined using the tissue culture plate method. The effects of TDN on the expression of QS genes and efflux pump genes were tested using real-time polymerase chain reaction (RT-PCR). The average size of the TDNs was 64.77 nm. It was found that TDN showed a significant reduction in biofilm formation (96%) and represented superior antibacterial activity against P. aeruginosa strains in comparison to titanium dioxide powder. In addition, the use of TDN alone or in combination with antibiotics resulted in significant downregulation of the efflux pump genes (MexY, MexB, MexA) and QS-regulated genes (lasR, lasI, rhll, rhlR, pqsA, pqsR) in comparison to the untreated isolate. TDN can increase the therapeutic efficacy of traditional antibiotics by affecting efflux pump expression and quorum-sensing genes controlling biofilm production.

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Synthesis of the Bacteriostatic Poly(L-Lactide) by Using Zinc (II)[(acac)(L)H2O] (L = Aminoacid-Based Chelate Ligands) as an Effective ROP Initiator

International Journal of Molecular Sciences ◽

10.3390/ijms22136950 ◽

2021 ◽

Vol 22 (13) ◽

pp. 6950

Author(s):

Renata Barczyńska-Felusiak ◽

Małgorzata Pastusiak ◽

Piotr Rychter ◽

Bożena Kaczmarczyk ◽

Michał Sobota ◽

...

Keyword(s):

Schiff Bases ◽

Antibacterial Properties ◽

Antimicrobial Effect ◽

Zinc Complexes ◽

Antibacterial And Antifungal Activities ◽

Aspergillus Brasiliensis ◽

Acetylacetonate Complex ◽

Distorted Trigonal Bipyramid ◽

Composition Structure ◽

Antibacterial And Antifungal

The paper presents a synthesis of poly(l-lactide) with bacteriostatic properties. This polymer was obtained by ring-opening polymerization of the lactide initiated by selected low-toxic zinc complexes, Zn[(acac)(L)H2O], where L represents N-(pyridin-4-ylmethylene) tryptophan or N-(2-pyridin-4-ylethylidene) phenylalanine. These complexes were obtained by reaction of Zn[(acac)2 H2O] and Schiff bases, , the products of the condensation of amino acids and 4-pyridinecarboxaldehyde. The composition, structure, and geometry of the synthesized complexes were determined by NMR and FTIR spectroscopy, elemental analysis, and molecular modeling. Both complexes showed the geometry of a distorted trigonal bipyramid. The antibacterial and antifungal activities of both complexes were found to be much stronger than those of the primary Schiff bases. The present study showed a higher efficiency of polymerization when initiated by the obtained zinc complexes than when initiated by the zinc(II) acetylacetonate complex. The synthesized polylactide showed antibacterial properties, especially the product obtained by polymerization initiated by a zinc(II) complex with a ligand based on l-phenylalanine. The polylactide showed a particularly strong antimicrobial effect against Pseudomonas aeruginosa, Staphylococcus aureus, and Aspergillus brasiliensis. At the same time, this polymer does not exhibit fibroblast cytotoxicity.

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Y3+ substituted Sr-hexaferrites: sol-gel synthesis, structural, magnetic and electrical characterization

Cerâmica ◽

10.1590/0366-69132019653742582 ◽

2019 ◽

Vol 65 (374) ◽

pp. 274-281 ◽

Cited By ~ 3

Author(s):

S. S. Satpute ◽

S. R. Wadgane ◽

S. R. Kadam ◽

D. R. Mane ◽

R. H. Kadam

Keyword(s):

Electron Microscopy ◽

Sol Gel ◽

Electrical Characterization ◽

Combustion Method ◽

Hexagonal Structure ◽

Strontium Hexaferrite ◽

X Ray Diffraction ◽

X Ray ◽

Morphological Studies ◽

Auto Combustion

Abstract Y3+ substituted strontium hexaferrites having chemical composition SrYxFe12-xO19 (x= 0.0, 0.5, 1.0, 1.5) were successfully synthesized by sol-gel auto-combustion method. The structural and morphological studies of prepared samples were investigated by using X-ray diffraction technique, energy dispersive X-ray spectroscopy, field emission scanning electron microscopy (FE-SEM) and high-resolution transmission electron microscopy. The X-ray diffraction pattern confirmed the single-phase hexagonal structure of yttrium substituted strontium ferrite and the lattice parameters a and c increased with the substitution of Y3+ ions. The crystallite size also varied with x content from 60 to 80 nm. The morphology was studied by FE-SEM, and the grain size of nanoparticles ranged from 44 to 130 nm. The magnetic properties were investigated by using vibrating sample magnetometer. The value of saturation magnetization decreased from 49.60 to 35.40 emu/g. The dielectric constant decreased non-linearly whereas the electrical dc resistivity increased with the yttrium concentration in strontium hexaferrite.

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