Impact of sintering temperature on the phase composition and antibacterial properties of silver-doped hydroxyapatite

2013 ◽  
Vol 85 (2) ◽  
pp. 453-462 ◽  
Author(s):  
Arita Dubnika ◽  
Dagnija Loca ◽  
Aigars Reinis ◽  
Maris Kodols ◽  
Liga Berzina-Cimdina
Keyword(s):  
Phase Composition ◽  
Silver Oxide ◽  
Sintering Temperature ◽  
Antibacterial Properties ◽  
Phase Changes ◽  
Precipitation Method ◽  
Sintering Process ◽  
Bacterial Strains ◽  
The Impact

In the present study, the impact of sintering temperature on the phase composition and antibacterial properties of silver-doped hydroxyapatite (HAp/Ag) samples was investigated. HAp/Ag containing 0.2 and 1.2 % silver was prepared using a modified wet chemical precipitation method. The surface morphology and inner structure of the sintered samples were discussed. X-ray powder diffraction (XRD) and scanning electron microscopy (SEM) studies showed that, after the sintering process, HAp/Ag contained a silver oxide phase, which was not observed in raw materials. Phase composition changes at different sintering temperatures were studied, and it was found that silver oxide undergoes phase changes during the sintering process. In vitro antibacterial properties approved the excellent antimicrobial activity of HAp/Ag against the bacterial strains Staphylococcus epidermidis and Pseudomonas aeruginosa. The HAp/Ag sample with 1.2 % silver content, sintered at 1150 °C, showed the highest antibacterial activity.

scholarly journals Effect of Gold Nanoparticles and Silicon on the Bioactivity and Antibacterial Properties of Hydroxyapatite/Chitosan/Tricalcium Phosphate-Based Biomicroconcretes

Materials ◽  
2021 ◽  
Vol 14 (14) ◽  
pp. 3854
Author(s):  
Joanna Czechowska ◽  
Ewelina Cichoń ◽  
Anna Belcarz ◽  
Anna Ślósarczyk ◽  
Aneta Zima
Keyword(s):  
Gold Nanoparticles ◽  
Antibacterial Activity ◽  
Tricalcium Phosphate ◽  
Setting Time ◽  
Antibacterial Properties ◽  
Bone Substitutes ◽  
Bacterial Strains ◽  
Setting Times ◽  
Biological Studies

Bioactive, chemically bonded bone substitutes with antibacterial properties are highly recommended for medical applications. In this study, biomicroconcretes, composed of silicon modified (Si-αTCP) or non-modified α-tricalcium phosphate (αTCP), as well as hybrid hydroxyapatite/chitosan granules non-modified and modified with gold nanoparticles (AuNPs), were designed. The developed biomicroconcretes were supposed to combine the dual functions of antibacterial activity and bone defect repair. The chemical and phase composition, microstructure, setting times, mechanical strength, and in vitro bioactive potential of the composites were examined. Furthermore, on the basis of the American Association of Textile Chemists and Colorists test (AATCC 100), adapted for chemically bonded materials, the antibacterial activity of the biomicroconcretes against S. epidermidis, E. coli, and S. aureus was evaluated. All biomicroconcretes were surgically handy and revealed good adhesion between the hybrid granules and calcium phosphate-based matrix. Furthermore, they possessed acceptable setting times and mechanical properties. It has been stated that materials containing AuNPs set faster and possess a slightly higher compressive strength (3.4 ± 0.7 MPa). The modification of αTCP with silicon led to a favorable decrease of the final setting time to 10 min. Furthermore, it has been shown that materials modified with AuNPs and silicon possessed an enhanced bioactivity. The antibacterial properties of all of the developed biomicroconcretes against the tested bacterial strains due to the presence of both chitosan and Au were confirmed. The material modified simultaneously with AuNPs and silicon seems to be the most promising candidate for further biological studies.

scholarly journals Synthesis, Characterization, Antibacterial Properties, and In Vitro Studies of Selenium and Strontium Co-Substituted Hydroxyapatite

2021 ◽  
Vol 22 (8) ◽  
pp. 4246
Author(s):  
Muhammad Maqbool ◽  
Qaisar Nawaz ◽  
Muhammad Atiq Ur Atiq Ur Rehman ◽  
Mark Cresswell ◽  
Phil Jackson ◽  
...  
Keyword(s):  
Negative Impact ◽  
Antibacterial Properties ◽  
Biological Properties ◽  
Ion Concentration ◽  
Charge Composition ◽  
Bacterial Strains ◽  
X Ray Diffraction ◽  
Molar Ratios ◽  
Human Osteosarcoma Cells

In this study, as a measure to enhance the antimicrobial activity of biomaterials, the selenium ions have been substituted into hydroxyapatite (HA) at different concentration levels. To balance the potential cytotoxic effects of selenite ions (SeO32−) in HA, strontium (Sr2+) was co-substituted at the same concentration. Selenium and strontium-substituted hydroxyapatites (Se-Sr-HA) at equal molar ratios of x Se/(Se + P) and x Sr/(Sr + Ca) at (x = 0, 0.01, 0.03, 0.05, 0.1, and 0.2) were synthesized via the wet precipitation route and sintered at 900 °C. The effect of the two-ion concentration on morphology, surface charge, composition, antibacterial ability, and cell viability were studied. X-ray diffraction verified the phase purity and confirmed the substitution of selenium and strontium ions. Acellular in vitro bioactivity tests revealed that Se-Sr-HA was highly bioactive compared to pure HA. Se-Sr-HA samples showed excellent antibacterial activity against both Gram-negative (Escherichia coli) and Gram-positive (Staphylococcus carnosus) bacterial strains. In vitro cell–material interaction, using human osteosarcoma cells MG-63 studied by WST-8 assay, showed that Se-HA has a cytotoxic effect; however, the co-substitution of strontium in Se-HA offsets the negative impact of selenium and enhanced the biological properties of HA. Hence, the prepared samples are a suitable choice for antibacterial coatings and bone filler applications.

Improvement of carotenoid bioaccessibility from spinach by co-ingesting with excipient nanoemulsions: impact of the oil phase composition

2019 ◽  
Vol 10 (9) ◽  
pp. 5302-5311 ◽  
Author(s):  
Kangfei Yao ◽  
David Julian McClements ◽  
Jiaxin Xiang ◽  
Ziying Zhang ◽  
Yong Cao ◽  
...  
Keyword(s):  
Phase Composition ◽  
The Impact

This study revealed the impact of the oil phase composition on carotenoid bioaccessibility when they were co-ingested with spinach, using an in vitro model.

scholarly journals Antibacterial Activity of Leukocyte- and Platelet-Rich Plasma: AnIn VitroStudy

2018 ◽  
Vol 2018 ◽  
pp. 1-8 ◽  
Author(s):  
Agata Cieślik-Bielecka ◽  
Tadeusz Bold ◽  
Grzegorz Ziółkowski ◽  
Marcin Pierchała ◽  
Aleksandra Królikowska ◽  
...  
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Enterococcus Faecalis ◽  
Platelet Rich Plasma ◽  
Antibacterial Properties ◽  
Antimicrobial Effect ◽  
Diffusion Method ◽  
Bacterial Strains ◽  
Bovine Thrombin ◽  
Zones Of Inhibition

The aim of the study was to investigate the leukocyte- and platelet-rich plasma (L-PRP) antimicrobial activity. The studied sample comprised 20 healthy males. The L-PRP gel, liquid L-PRP, and thrombin samples were testedin vitrofor their antibacterial properties against selected bacterial strains using the Kirby-Bauer disc diffusion method. Two types of thrombin were used (autologous and bovine). Zones of inhibition produced by L-PRP ranged between 6 and 18 mm in diameter. L-PRP inhibited the growth ofStaphylococcus aureus(MRSA and MSSA strains) and was also active againstEnterococcus faecalisandPseudomonas aeruginosa. There was no activity againstEscherichia coliandKlebsiella pneumoniae. The statistically significant increase of L-PRP antimicrobial effect was noted with the use of major volume of thrombin as an activator. Additionally, in groups where a bovine thrombin mixture was added to L-PRP the zones of inhibition concerning MRSA,Enterococcus faecalis, andPseudomonas aeruginosawere larger than in the groups with autologous thrombin. Based on the conducted studies, it can be determined that L-PRP can evokein vitroantimicrobial effects and might be used to treat selected infections in the clinical field. The major volume of thrombin as an activator increases the strength of the L-PRP antimicrobial effect.

scholarly journals Antibacterial properties of capsaicin and its derivatives and their potential to fight antibiotic resistance – A literature survey

2021 ◽  
Author(s):  
Samuel Füchtbauer ◽  
Soraya Mousavi ◽  
Stefan Bereswill ◽  
Markus M. Heimesaat
Keyword(s):  
Antibiotic Resistance ◽  
Bacterial Infections ◽  
Molecular Mechanisms ◽  
Antibacterial Properties ◽  
Treatment Strategies ◽  
Natural Compounds ◽  
Literature Survey ◽  
Bacterial Strains ◽  
Antibacterial Effects

AbstractAntibiotic resistance is endangering public health globally and gives reason for constant fear of virtually intractable bacterial infections. Given a limitation of novel antibiotic classes brought to market in perspective, it is indispensable to explore novel, antibiotics-independent ways to fight bacterial infections. In consequence, the antibacterial properties of natural compounds have gained increasing attention in pharmacological sciences. We here performed a literature survey regarding the antibacterial effects of capsaicin and its derivatives constituting natural compounds of chili peppers. The studies included revealed that the compounds under investigation exerted i.) both direct and indirect antibacterial properties in vitro depending on the applied concentrations and the bacterial strains under investigation; ii.) synergistic antibacterial effects in combination with defined antibiotics; iii.) resistance-modification via inhibition of bacterial efflux pumps; iv.) attenuation of bacterial virulence factor expression; and v.) dampening of pathogen-induced immunopathological responses. In conclusion, capsaicin and its derivatives comprise promising antimicrobial molecules which could complement or replace antibiotic treatment strategies to fight bacterial infections. However, a solid basis for subsequent clinical trials requires future investigations to explore the underlying molecular mechanisms and in particular pharmaceutical evaluations in animal infection models.

scholarly journals Bioactive Healing Abutment as a Potential Tool for the Treatment of Peri-Implant Disease—In Vitro Study

2020 ◽  
Vol 10 (15) ◽  
pp. 5376
Author(s):  
Bartłomiej Iwańczyk ◽  
Piotr Wychowański ◽  
Anna Minkiewicz-Zochniak ◽  
Kamila Strom ◽  
Sylwia Jarzynka ◽  
...  
Keyword(s):  
Drug Carrier ◽  
In Vitro Study ◽  
Bacterial Strains ◽  
Disk Diffusion Assay ◽  
New Treatment ◽  
Micro Organisms ◽  
Staphylococcus Spp ◽  
The Impact ◽  
Potential Tool

The common use of dental implants for dental reconstruction poses new treatment challenges for physicians, peri-implantitis being a particularly difficult one. Micro-organisms, including drug-resistant Staphylococcus spp. strains, play a crucial role in the etiology of peri-implantitis. In this paper, the authors assess the efficacy of a bioactive healing abutment (BHA) of their own design for the local release of antibiotics as a potential tool for the treatment of peri-implant disease. BHA filled with a collagen material, combined with the antibiotics clindamycin and tetracycline, was tested in vitro by disk diffusion assay. Antibacterial activity was observed for the chosen Staphylococcus aureus and Staphylococcus epidermidis bacterial strains. In addition, the impact of titanium discs (which were used to make the BHA) was monitored. The results show that the zone diameter breakpoints for BHA are higher than those of standard absorbent paper discs in both tested strains for both tested antibiotics. This work demonstrates that the proposed BHA can serve as an effective and precise drug carrier. The release of antibiotics from the described implant device is easy to control and allows for an effective local antibacterial in vitro treatment. The procedure is inexpensive, easy to perform, and repeatable.

Preparation of Nanosized La2CuO4 Particle by Chemical Precipitation Method and its Thermoelectrical Properties

2008 ◽  
Vol 368-372 ◽  
pp. 556-558
Author(s):  
Yong Liu ◽  
Yuan Hua Lin ◽  
Bo Ping Zhang ◽  
Ce Wen Nan ◽  
Jing Feng Li
Keyword(s):  
Phase Composition ◽  
Reaction Mechanism ◽  
Seebeck Coefficient ◽  
Sintering Temperature ◽  
Chemical Precipitation ◽  
Impurity Phase ◽  
Chemical Precipitation Method ◽  
Precipitation Method ◽  
Ceramic Samples ◽  
Precursor Powders

Nanometer La2CuO4 particles have been prepared using chemical precipitation method. The reaction mechanism, microstructure and phase composition of the samples were investigated by TG-DTA, XRD, SEM. The XRD results showed that pure La2CuO4 phase can be obtained by calcining the La-Cu-O-H precursor powders at 900 oC for 2 h, and the impurity phase will appear in the La2CuO4 ceramic as increasing the sintering temperature over 1200 oC. La2CuO4 ceramic samples sintered at 950 oC for 6 h exhibit good thermoelectric properties. Seebeck coefficient can reach 714 μV/K, and power factor is about 2.33×10-5 W/mK2.

scholarly journals Synthesis of Copper Nanoparticles by Thermal Decomposition and Their Antimicrobial Properties

2014 ◽  
Vol 2014 ◽  
pp. 1-5 ◽  
Author(s):  
R. Betancourt-Galindo ◽  
P. Y. Reyes-Rodriguez ◽  
B. A. Puente-Urbina ◽  
C. A. Avila-Orta ◽  
O. S. Rodríguez-Fernández ◽  
...  
Keyword(s):  
Thermal Decomposition ◽  
Copper Nanoparticles ◽  
Copper Chloride ◽  
Metallic Copper ◽  
Antibacterial Properties ◽  
Antimicrobial Properties ◽  
Face Centered Cubic ◽  
Bacterial Strains ◽  
Tem Analysis

Copper nanoparticles were synthesized by thermal decomposition using copper chloride, sodium oleate, and phenyl ether as solvent agents. The formation of nanoparticles was evidenced by the X-ray diffraction and transmission electron microscopy. The peaks in the XRD pattern correspond to the standard values of the face centered cubic (fcc) structure of metallic copper and no peaks of other impurity crystalline phases were detected. TEM analysis showed spherical nanoparticles with sizes in the range of 4 to 18 nm. The antibacterial properties of copper nanoparticles were evaluatedin vitroagainst strains ofStaphylococcus aureusandPseudomonas aeruginosa. The antibacterial activity of copper nanoparticles synthesized by thermal decomposition showed significant inhibitory effect against these highly multidrug-resistant bacterial strains.

The Optimization of Sintering Process for Alumina Extraction from Fly Ash

2014 ◽  
Vol 878 ◽  
pp. 264-270 ◽  
Author(s):  
Xiao Huan Wang ◽  
Bao Dong Wang ◽  
Yong Feng Xiao ◽  
Xiao Ting Liu ◽  
Li Jun Zhao ◽  
...  
Keyword(s):  
Response Surface Methodology ◽  
Fly Ash ◽  
Six Sigma ◽  
Sintering Temperature ◽  
High Alumina ◽  
The Novel ◽  
Sintering Process ◽  
Novel Method ◽  
The Impact ◽  
Six Sigma Approach

The objective of paper is to optimize the variables of the sintering process with the six sigma philosophy. The impact of sintering temperature, Ca ratio, Na ratio and reaction time on the alumina reaching rate were primarily studied. In the research, a novel method was adopted to efficiently recover alumina and silica from high-alumina fly ash, and the response surface methodology of six sigma approach was also implemented to analysis the results obtained by the experiments. There is great significance to optimize sintering process for the industrialization of the novel method. Amount of energy consumption will be reduced in the production.

scholarly journals Unravelling the antimicrobial action of antidepressants on gut commensal microbes

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Yasmina Ait Chait ◽  
Walid Mottawea ◽  
Thomas A. Tompkins ◽  
Riadh Hammami
Keyword(s):  
Antimicrobial Activity ◽  
Gut Microbiota ◽  
Antidepressant Drugs ◽  
Dilution Method ◽  
Bacterial Strains ◽  
Bifidobacterium Animalis ◽  
Colony Counting ◽  
The Stability ◽  
The Impact

Abstract Over the past decade, there has been increasing evidence highlighting the implication of the gut microbiota in a variety of brain disorders such as depression, anxiety, and schizophrenia. Studies have shown that depression affects the stability of gut microbiota, but the impact of antidepressant treatments on microbiota structure and metabolism remains underexplored. In this study, we investigated the in vitro antimicrobial activity of antidepressants from different therapeutic classes against representative strains of human gut microbiota. Six different antidepressants: phenelzine, venlafaxine, desipramine, bupropion, aripiprazole and (S)-citalopram have been tested for their antimicrobial activity against 12 commensal bacterial strains using agar well diffusion, microbroth dilution method, and colony counting. The data revealed an important antimicrobial activity (bacteriostatic or bactericidal) of different antidepressants against the tested strains, with desipramine and aripiprazole being the most inhibitory. Strains affiliating to most dominant phyla of human microbiota such as Akkermansia muciniphila, Bifidobacterium animalis and Bacteroides fragilis were significantly altered, with minimum inhibitory concentrations (MICs) ranged from 75 to 800 μg/mL. A significant reduction in bacterial viability was observed, reaching 5 logs cycle reductions with tested MICs ranged from 400 to 600 μg/mL. Our findings demonstrate that gut microbiota could be altered in response to antidepressant drugs.

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