Preparation and Characterization of the Transparent Hybrids of Silicone Epoxy Resin and Titanium Dioxide Nanoparticles via Sol–Gel Reactions

2011 ◽  
Vol 11 (8) ◽  
pp. 7202-7205 ◽  
Author(s):  
Kwok Wai Lem ◽  
Dinh Huong Nguyen ◽  
Han Na Kim ◽  
Dai Soo Lee
Antibiotics ◽  
2021 ◽  
Vol 10 (6) ◽  
pp. 625
Author(s):  
Fatma Y. Ahmed ◽  
Usama Farghaly Aly ◽  
Rehab Mahmoud Abd El-Baky ◽  
Nancy G. F. M. Waly

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.


2014 ◽  
Vol 15 (8) ◽  
pp. 593-605 ◽  
Author(s):  
Zhuan-xi Luo ◽  
Zhen-hong Wang ◽  
Bin Xu ◽  
Ionnis L. Sarakiotis ◽  
Gijs Du Laing ◽  
...  

Author(s):  
Nitesh Parmar ◽  
Jitendra Kumar Srivastava

Abstract This study is an attempt to the removal of Ciprofloxacin (CIP) antibiotic from simulated wastewater using a photocatalytic process. The photocatalytic process was carried out in a photocatalytic reactor in the presence of TiO2 nanoparticles. TiO2 nanoparticles were successfully prepared in a laboratory scale using sol-gel method with titanium-isopropoxide (TTIP) as titanium precursor. Prepared material was found very effective to the removal of CIP antibiotic. The maximum removal efficiency of 87.95% of ciprofloxacin from aqueous solution was achieved at the pH 5, catalyst doze of 40 mg L−1 with initial concentration of ciprofloxacin 5 mg L−1, and the reaction time of 100 min additionally; material characterization of TiO2 was presented in detail in terms of XRD, SEM, UV, and FTIR. It has been found that at the optimum condition the total operating cost indicated for the removal of ciprofloxacin from aqueous solution is 786.56 (INR/kg of CIP removal). This technique demonstrated that photocatalytic reaction in presence of TiO2 nanoparticles is well applicable to treat pharmaceutical wastewater.


2020 ◽  
Vol 854 ◽  
pp. 45-50
Author(s):  
Ekaterina N. Gubareva ◽  
Valeria V. Strokova ◽  
Yulia N. Ogurtsova ◽  
Pavel S. Baskakov ◽  
Lok Pratap Singh

The paper presents the process of sol-gel synthesis of titanium dioxide nanoparticles, the peculiarities of the influence of component composition (titanium precursor content, solvent and stabilizer − surfactant) on the properties of sol and powder obtained on its basis. As a result of the study, the nature of the influence of the type and content of the surfactant in the solution of tetrabutoxytitanium in ethanol on the size of the synthesized particles of titanium dioxide was revealed. The optimal composition of the reaction mixture of TiO–R sol was obtained and the optimal ratio of tetrabutoxytitanium and ethyl alcohol was revealed using which a material with a high content of nanosized titanium dioxide was obtained.


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