scholarly journals Photonics of DNA/ruthenium(II) complexes

Nanophotonics ◽  
2018 ◽  
Vol 7 (8) ◽  
pp. 1373-1385 ◽  
Author(s):  
Norihisa Kobayashi ◽  
Haruki Minami ◽  
Kazuki Nakamura
Keyword(s):  
Titanium Dioxide ◽  
Response Time ◽  
Electrode Surface ◽  
Hybrid Film ◽  
Titanium Dioxide Nanoparticles ◽  
Photoelectrochemical Properties ◽  
Applied Frequency ◽  
Turn On ◽  
Electrophoretic Migration ◽  
Micrometer Scale

AbstractIn this review, we describe the investigation of a ruthenium [Ru(II)] complex-based, AC voltage-driven, electrochemiluminescent (ECL) device first. The ECL turn-on response time and intensity were dramatically improved by introducing the AC method. The turn-on response time was speeded up by increasing the applied frequency: 4 ms response time was achieved at 200 Hz, which was much faster than when using the DC method (1.5 s). We also introduced rutile-type titanium dioxide nanoparticles (TiO2NPs) in a Ru(II) complex-based AC-ECL device. The ECL intensity and the lifetimes of the ECL device with TiO2NPs were greatly improved compared to those of the device without nanoparticles. Then we tried to improve photoelectrochemical properties of the Ru(II) complex by combining it with DNA molecules. We fabricated a novel DNA/Ru(bpy)32+hybrid film that could immobilize the ECL-active Ru(bpy)32+onto the electrode surface through electrophoretic migration. The hybrid film contained unique micrometer-scale aggregates of Ru(bpy)32+in the DNA matrix. Surprisingly, by using the DNA/Ru(bpy)32+hybrid film for the ECL device, luminescence could be obtained at frequencies as high as 10kHz, which corresponds to a response time shorter than 100μs.

scholarly journals Salt Stress Mitigation via the Foliar Application of Chitosan-Functionalized Selenium and Anatase Titanium Dioxide Nanoparticles in Stevia (Stevia rebaudiana Bertoni)

Molecules ◽  
2021 ◽  
Vol 26 (13) ◽  
pp. 4090
Author(s):  
Morteza Sheikhalipour ◽  
Behrooz Esmaielpour ◽  
Gholamreza Gohari ◽  
Maryam Haghighi ◽  
Hessam Jafari ◽  
...  
Keyword(s):  
Titanium Dioxide ◽  
Salt Stress ◽  
Titanium Dioxide Nanoparticles ◽  
Chitosan Nanoparticles ◽  
Stevia Rebaudiana ◽  
High Salt ◽  
Steviol Glycosides ◽  
Rebaudioside A ◽  
Tio2 Nps ◽  
Stevia Rebaudiana Bertoni

High salt levels are one of the significant and major limiting factors on crop yield and productivity. Out of the available attempts made against high salt levels, engineered nanoparticles (NPs) have been widely employed and considered as effective strategies in this regard. Of these NPs, titanium dioxide nanoparticles (TiO2 NPs) and selenium functionalized using chitosan nanoparticles (Cs–Se NPs) were applied for a quite number of plants, but their potential roles for alleviating the adverse effects of salinity on stevia remains unclear. Stevia (Stevia rebaudiana Bertoni) is one of the reputed medicinal plants due to their diterpenoid steviol glycosides (stevioside and rebaudioside A). For this reason, the current study was designed to investigate the potential of TiO2 NPs (0, 100 and 200 mg L−1) and Cs–Se NPs (0, 10 and 20 mg L−1) to alleviate salt stress (0, 50 and 100 mM NaCl) in stevia. The findings of the study revealed that salinity decreased the growth and photosynthetic traits but resulted in substantial cell damage through increasing H2O2 and MDA content, as well as electrolyte leakage (EL). However, the application of TiO2 NPs (100 mg L−1) and Cs–Se NPs (20 mg L−1) increased the growth, photosynthetic performance and activity of antioxidant enzymes, and decreased the contents of H2O2, MDA and EL under the saline conditions. In addition to the enhanced growth and physiological performance of the plant, the essential oil content was also increased with the treatments of TiO2 (100 mg L−1) and Cs–Se NPs (20 mg L−1). In addition, the tested NPs treatments increased the concentration of stevioside (in the non-saline condition and under salinity stress) and rebaudioside A (under the salinity conditions) in stevia plants. Overall, the current findings suggest that especially 100 mg L−1 TiO2 NPs and 20 mg L−1 Cs–Se could be considered as promising agents in combating high levels of salinity in the case of stevia.

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

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
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.

Impact of titanium dioxide nanoparticles on intestinal community in the 2,4,6-Trinitrobenzenesulfonic acid (TNBS)-induced acute colitis mice and the intervention effect of vitamin E

Nanoscale ◽  
2020 ◽  
Author(s):  
Yanjun Gao ◽  
Tingyu Li ◽  
Shuming Duan ◽  
Lizhi Lv ◽  
Yuan Li ◽  
...  
Keyword(s):  
Antibacterial Activity ◽  
Titanium Dioxide ◽  
Vitamin E ◽  
Titanium Dioxide Nanoparticles ◽  
Trinitrobenzenesulfonic Acid ◽  
Acute Colitis ◽  
Intervention Effect ◽  
Tio2 Nps

Titanium dioxide nanoparticles (TiO2-NPs) is widely applicated as additives in foods for its excellent whitening and brightening capability. Although the toxicity and antibacterial activity of TiO2-NPs has been extensively studied,...

scholarly journals Blackening of titanium dioxide nanoparticles by atomic hydrogen and the effect of coexistence of water on the blackening

RSC Advances ◽  
2021 ◽  
Vol 11 (7) ◽  
pp. 4270-4275
Author(s):  
Masahide Fujimoto ◽  
Masuaki Matsumoto ◽  
Naoki Nagatsuka ◽  
Katsuyuki Fukutani
Keyword(s):  
Titanium Dioxide ◽  
Atomic Hydrogen ◽  
Titanium Dioxide Nanoparticles

A fast blackening process of titanium dioxide nanoparticles by exposing to atomic hydrogen was studied by estimating the color of the nanoparticles.

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