scholarly journals Detection and Difference Analysis of the Enzyme Activity of Colloidal Gold Nanoparticles With Negatively Charged Surfaces Prepared by Different Reducing Agents

2022 ◽  
Vol 9 ◽  
Author(s):  
Mingze Ma ◽  
Junjun Cao ◽  
Ashe Fang ◽  
Zhihua Xu ◽  
Tieying Zhang ◽  
...  

Nanozymes are particles with diameters in the range of 1–100 nm, which has been widely studied due to their biological enzyme-like properties and stability that natural enzymes do not have. In this study, several reducing agents with different structures (catechol (Cc), hydroquinone (Hq), resorcinol (Rs), vitamin C (Vc), pyrogallic acid (Ga), sodium citrate (Sc), sodium malate (Sm), and sodium tartrate (St)) were used to prepare colloidal gold with a negative charge and similar particle size by controlling the temperature and pH. The affinity analysis of the substrate H2O2 and TMB showed that the order of activities of colloidal gold Nanozymes prepared by different reducing agents was Cc, Hq, Rs, Vc, Ga, Sc, Sm, St. It was also found that the enzyme activity of colloidal gold reduced by benzene rings is higher than that of the colloidal gold enzyme reduced by linear chains. Finally, we discussed the activity of the colloidal gold peroxidase based on the number and position of isomers and functional groups; and demonstrated that the nanozymes activity is affected by the surface activity of colloidal gold, the elimination of hydroxyl radicals and the TMB binding efficiency.

2021 ◽  
Author(s):  
Junjun Cao ◽  
Jie Zhang ◽  
Ning Yuan ◽  
Yixiao Sun ◽  
Zhihua Xu ◽  
...  

Abstract Research on the activity of nanoenzymes has always been a focus of nanomaterials. In this study, several reducing agents with different structures were used to prepare colloidal gold with a negative charge and similar size by controlling the temperature and pH. The affinity analysis of the substrate H 2 O 2 and TMB showed that the activity of colloidal gold nanoenzymes prepared by different reducing agents was in the order of Cc, Hq, Rs, Vc, Ga, Sc, Sm, St. The rule is that the enzyme activity of colloidal gold reduced by benzene ring is higher than that of colloidal gold enzyme reduced by linear chain. Finally, we discussed the activity of colloidal gold peroxidase from the number and position of isomers and functional groups, and demonstrated that the nanoenzyme activity affected the surface activity of colloidal gold, the elimination of hydroxyl radical and TMB binding efficiency.


2020 ◽  
Vol 90 (19-20) ◽  
pp. 2245-2257
Author(s):  
Zhong Zhao ◽  
Mingwen Zhang ◽  
Chris Hurren ◽  
Liming Zhou ◽  
Jihong Wu ◽  
...  

In this study, inorganic and organic UV absorbers, as well as reducing agents, were employed to treat cotton fabrics that were pre-dyed with two natural dyes (sodium copper chlorophyllin and gardenia yellow) to improve light fastness. The performance of UV absorbers and reducing agents was evaluated by comparing ΔE (CIELAB) of the treated samples caused by their exposure to simulated sunlight irradiation. Results show that both inorganic and organic UV absorbers present unsatisfactory effects on inhibiting the photo-fading of dyes, while the reducing agents (i.e. sodium citrate and glucose) exhibit distinctive effects on improving their light fastness. The protection was enhanced when the amount of the two reducing agents was increased from 1% to 5% o.w.f. Sodium citrate was found to be more efficient than glucose in this regard. Change in shade of gardenia yellow and sodium copper chlorophyllin pre-dyed fabrics with a treatment of 5% o.w.f. sodium citrate after 10 h exposure to simulated sunlight were ΔE 3.95 and 2.46, while for the controls were ΔE 10.34 and 8.11, respectively.


Minerals ◽  
2019 ◽  
Vol 9 (11) ◽  
pp. 705 ◽  
Author(s):  
Jianhua Kang ◽  
Yuehua Hu ◽  
Wei Sun ◽  
Zhiyong Gao ◽  
Runqing Liu

This study presents a highly selective reagent system that utilizes sodium hexametaphosphate (SHMP) to improve the separation of scheelite from calcite and fluorite using an anionic–nonionic collector. The recoveries of calcite and fluorite decreased to 20% as the SHMP dose exceeded 6 × 10−6 mol/L, whereas that of scheelite remained at 85%. The interaction mechanisms of minerals with SHMP were investigated through equilibrium speciation, Zeta potential, Fourier transform infrared spectrometry, and X-ray photoelectron spectroscopy analyses. SHMP exists as hydrogen phosphate anion in the aqueous solution with a pH of 7–12. Moreover, it may be adsorbed intensively on the positively charged surfaces of calcite and fluorite via electrostatic force or chelation with calcium ion to impede further adsorption of the assembled collector. By comparison, the adsorption of SHMP is feeble on the scheelite surface because of its negative charge. The roughing grade of low-grade scheelite ore is substantially improved from 0.74% to 1.65% compared with that in the contrast test in the absence of SHMP.


2017 ◽  
Vol 218 ◽  
pp. 285-293 ◽  
Author(s):  
Xiaolin Jin ◽  
Runqiang Yang ◽  
Liping Guo ◽  
Xinkun Wang ◽  
Xiaokun Yan ◽  
...  

Author(s):  
Guan Tinglu ◽  
Arati Ghosh ◽  
Bijan K. Ghosh

Secretory proteins have been localized in bacterial cells by inmunoelectron-microscopy and cytochemical methods. Although ferritin-antibody technique is satisfactory for the localization of single antigenic sites, multiple labelling is not possible by this technique. However, such multiple labelling is possible using colloidal gold antibody because colloidal gold of widely varying sizes can be prepared by simple laboratory manipulation. We prepared colloidal gold of two different sizes and labelled these with anti-penicillinase and anti-alkaline phosphatase antibodies. These labels were used to determine the location of penicillinase and alkaline phosphatase in secreting Bacillus licheniformis 749/C cells.Large colloidal gold particles (150Å) were prepared by 10% sodium citrate treatment of 0.01% HAuCl4; the pH of this colloidal gold suspension was adjusted to 7.6 with 0.2 M K2CO3. Small colloidal particles (50A) were prepared by treating 0.01% HAuCl4, after pH was adjusted to 8.0 with 0.2M K2CO3, withphosphorous saturated ether. The large or small gold particles (1010 in 10 ml) were treated with 100μg of anti-alkaline phosphatase or anti-penicillinase antibodies; after thorough mixing unbound antibodies were removed by centrifugation.


2020 ◽  
Vol 31 (3) ◽  
pp. 1169-1180 ◽  
Author(s):  
Seraj Mohaghegh ◽  
Karim Osouli-Bostanabad ◽  
Hossein Nazemiyeh ◽  
Yousef Javadzadeh ◽  
Alireza Parvizpur ◽  
...  

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