Immobilization adjusted clock reaction in the urea–urease–H<sup>+</sup> reaction system

Yang, Dan; Fan, Junhe; Cao, Fengyi; Deng, Zuojun; Ji, Lin

doi:10.1039/c8ra09244c

Cited by 17 publications

(14 citation statements)

References 27 publications

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“…As previously mentioned, Zn 2+ itself is a strong inhibitor for the enzyme, in addition to this, when the enzyme is embedded in the precipitate, the diffusion of the substrate towards the active sites is strongly hindered. The net result would be that the real concentration of reactive urea is much lower than the theoretical one, as it happens when urease is loaded on resin particles [12]. In amino resin particles, the bell shape is shifted to lower pH values and the stability of the enzyme is increased.…”

Section: Resultsmentioning

confidence: 95%

“…1) and since stoichiometrically twice ammonia is produced than carbon dioxide, the pH continuously increases in an unbuffered medium [42]. In experiments, the initial pH of the reaction mixture was set to pH ~ 4 by acetic acid, and due to the bell-shaped activity dependence of the enzyme on pH (having a maximum at pH = 8.2 [12]) a sigmoidal kinetic curve (pH versus time) can be obtained. Figure 1a shows typical kinetic curves obtained in the urea-urease enzymatic reaction, it can be seen that the clock time ranges between ~ 30 and ~ 200 s in the excess substrate (urea) depending on the enzyme concentration.…”

Section: Resultsmentioning

confidence: 99%

“…Because of their bell-shaped activity dependence on pH, certain enzymatic reactions can produce chemical clock type behavior in unbuffered media, if one or more products of the reaction itself affect the pH. One of the simplest systems showing such behavior is the hydrolysis of urea mediated by the enzyme urease to yield ammonia and carbon dioxide [10][11][12]. Urea-urease set was successfully employed for time programming of self-regulating supramolecular hydrogels [13,14], spatiotemporal control of the gelation and polymerization fronts [15], layered compartmentalization [16] and vesicles self-division [17][18][19].…”

Section: Introductionmentioning

confidence: 99%

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Inhibition of the urea-urease reaction by the components of the zeolite imidazole frameworks-8 and the formation of urease-zinc-imidazole hybrid compound

Német

Miele

Schuszter

et al. 2022

Reac Kinet Mech Cat

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In the past decade, much effort has been devoted to using chemical clock-type reactions in material design and driving the self-assembly of various building blocks. Urea-urease enzymatic reaction has chemical pH clock behavior in an unbuffered medium, in which the induction time and the final pH can be programmed by the concentrations of the reagents. The urea-urease reaction can offer a new alternative in material synthesis, where the pH and its course in time are crucial factors in the synthesis. However, before using it in any synthesis method, it is important to investigate the possible effects of the reagents on the enzymatic reaction. Here we investigate the effect of the reagents of the zeolite imidazole framework-8 (zinc ions and 2-methylimidazole) on the urea-urease reaction. We have chosen the zeolite imidazole framework-8 because its formation serves as a model reaction for the formation of other metal–organic frameworks. We found that, besides the inhibition effect of the zinc ions which is well-known in the literature, 2-methylimidazole inhibits the enzymatic reaction as well. In addition to the observed inhibition effect, we report the formation of a hybrid urease-zinc-2-methylimidazole hybrid material. To support the inhibition effect, we developed a kinetic model which reproduced qualitatively the experimentally observed kinetic curves.

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Section: Resultsmentioning

confidence: 95%

Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Inhibition of the urea-urease reaction by the components of the zeolite imidazole frameworks-8 and the formation of urease-zinc-imidazole hybrid compound

Német

Miele

Schuszter

et al. 2022

Reac Kinet Mech Cat

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“…Urease activity was quantified by measuring the O.D. at 530 nm using a UV–Visible spectrophotometer [ 35 ].…”

Section: Methodsmentioning

confidence: 99%

Tryptone-stabilized silver nanoparticles’ potential to mitigate planktonic and biofilm growth forms of Serratia marcescens

et al. 2022

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Several microbial pathogens are capable of forming biofilms. These microbial communities pose a serious challenge to the healthcare sector as they are quite difficult to combat. Given the challenges associated with the antibiotic-based management of biofilms, the research focus has now been shifted towards finding alternate treatment strategies that can replace or complement the antibacterial properties of antibiotics. The field of nanotechnology offers several novel and revolutionary approaches to eradicate biofilm-forming microbes. In this study, we evaluated the antibacterial and antibiofilm efficacy of in-house synthesized, tryptone-stabilized silver nanoparticles (Ts-AgNPs) against the superbug Serratia marcescens . The nanoparticles were of spherical morphology with an average hydrodynamic diameter of 170 nm and considerable colloidal stability with a Zeta potential of − 24 ± 6.15 mV. Ts-AgNPs showed strong antibacterial activities with a minimum inhibitory concentration (MIC 50 ) of 2.5 µg/mL and minimum bactericidal concentration (MBC) of 12.5 µg/mL against S. marcescens . The nanoparticles altered the cell surface hydrophobicity and inhibited biofilm formation. The Ts-AgNPs were also effective in distorting pre-existing biofilms by degrading the extracellular DNA (eDNA) component of the extracellular polymeric substance (EPS) layer. Furthermore, reduction in quorum-sensing (QS)-induced virulence factors produced by S. marcescens indicated that Ts-AgNPs attenuated the QS pathway. Together, these findings suggest that Ts-AgNPs are an important anti-planktonic and antibiofilm agent that can be explored for both the prevention and treatment of infections caused by S. marcescens . Graphical abstract Supplementary Information The online version contains supplementary material available at 10.1007/s00775-022-01977-w.

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“…Therefore, the enzyme-immobilized associative polyelectrolyte has greater activity, reversibility, and stability. [11] Angewandte Chemie…”

Section: Angewandte Chemiementioning

confidence: 99%

Biocatalytic Feedback‐Controlled Non‐Newtonian Fluids

et al. 2020

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Non‐Newtonian fluids are ubiquitous in daily life and industrial applications. Herein, we report an intelligent fluidic system integrating two distinct non‐Newtonian rheological properties mediated by an autocatalytic enzyme reaction. Associative polyelectrolytes bearing a small amount of ionic and alkyl groups are engineered: by carefully balancing the charge density and the hydrophobic effect, the polymer solutions demonstrate a unique shear thickening property at low pH while shear thinning at high pH. The urea‐urease clock reaction is utilized to program a feedback‐induced pH change, leading to a strong upturn of the nonlinear viscoelastic properties. As long as the chemical fuel is supplied, two distinct non‐Newtonian states can be achieved with a tunable lifetime span. As a proof of concept, we demonstrate how the physical energy‐driven nonequilibrium properties can be manipulated by a chemical‐fueled process.

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Immobilization adjusted clock reaction in the urea–urease–H⁺ reaction system

Abstract: The reported immobilization shifts the bell-shaped reactivity-pH curve to lower pHs and enables the clock reaction to occur from a very low initial pH, where the free enzyme had already lost its activity.

Cited by 17 publications

References 27 publications

Inhibition of the urea-urease reaction by the components of the zeolite imidazole frameworks-8 and the formation of urease-zinc-imidazole hybrid compound

Inhibition of the urea-urease reaction by the components of the zeolite imidazole frameworks-8 and the formation of urease-zinc-imidazole hybrid compound

Tryptone-stabilized silver nanoparticles’ potential to mitigate planktonic and biofilm growth forms of Serratia marcescens

Biocatalytic Feedback‐Controlled Non‐Newtonian Fluids

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Immobilization adjusted clock reaction in the urea–urease–H+ reaction system

Abstract: The reported immobilization shifts the bell-shaped reactivity-pH curve to lower pHs and enables the clock reaction to occur from a very low initial pH, where the free enzyme had already lost its activity.

Cited by 17 publications

References 27 publications

Inhibition of the urea-urease reaction by the components of the zeolite imidazole frameworks-8 and the formation of urease-zinc-imidazole hybrid compound

Inhibition of the urea-urease reaction by the components of the zeolite imidazole frameworks-8 and the formation of urease-zinc-imidazole hybrid compound

Tryptone-stabilized silver nanoparticles’ potential to mitigate planktonic and biofilm growth forms of Serratia marcescens

Biocatalytic Feedback‐Controlled Non‐Newtonian Fluids

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Immobilization adjusted clock reaction in the urea–urease–H⁺ reaction system