ANALYTICA CHIMICA ACTA
·
2016
·
IF 4.712
Hao-Hua Deng,Guo-Lin Hong,Feng-Lin Lin,Ai-Lin Liu,Xing-Hua Xia,Wei Chen
Herein, we reported for the first time that gold nanoparticles-catalyzed 3,3′,5,5′-tetramethylbenzidine-H 2 O 2 system can serve as an ultrasensitive colorimetric pH indicator. Gold nanoparticles acted as a catalyst and imitated the function of horseradish peroxidase . The absorbance at 450 nm of the yellow-color product in the catalytic reaction exhibited a linear fashion over the pH range of 6.40–6.60. On the basis of this property, we constructed a novel sensing platform for the determination of urea, urease , and urease inhibitor. The limit of detection for urea and urease was 5 μM and 1.8 U/L, respectively. The half-maximal inhibition value IC 50 of acetohydroxamic acid was found to be 0.05 mM. Urea in human urine and urease in soil were detected with satisfied results.
研究领域:
生物化学
·
分析化学
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产品关联
DOI
PubMed
高影响因子
COLLOIDS AND SURFACES A-PHYSICOCHEMICAL AND ENGINEERING ASPECTS
·
2025
·
IF 5.4
Aleksandr L. Kim,Egor V. Musin,Sergey A. Tikhonenko
Enzymatic analysis methods are widely used for the determination of low-molecular-weight substances in various fields; however, they have several limitations. One promising approach to addressing these limitations is the encapsulation of enzymes in polyelectrolyte microcapsules (PMCs). In this study, the development of a bienzymatic diagnostic system based on two separately encapsulated enzymes—urease and glucose oxidase (GO)—is proposed for the first time, enabling the simultaneous determination of urea and glucose concentrations in a single sample. To achieve this, the influence of reaction products and substrates of urease on the activity of GO, and vice versa, was investigated. It was demonstrated that ammonia reduces the activity of glucose oxidase, while gluconic acid and hydrogen peroxide decrease the activity of urease, with the PMC shell exhibiting protective properties for the encapsulated form of urease. Other reaction components did not affect the enzyme activities. The linear range, coefficient of variation, and reusability of this diagnostic system were determined: the linear range for urea concentration detection was found to be between 10 and 50 mM (coefficient of variation 2 %) with 7 reuses of same PMC-urease; the linear range for glucose concentration detection was between 30 and 100 mM (coefficient of variation 8 %) with 13 reuses of same PMC-GO. This diagnostic system is suitable for determining urea and glucose concentrations in industrial biofuel production and in industrial fermenters using urea as a nitrogen source.
研究领域:
生物化学
·
诊断学
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产品关联
DOI
高影响因子
JOURNAL OF HAZARDOUS MATERIALS
·
2025
·
IF 11.3
Yonghui Xing,Wenjing He,Changshui Cai,Song Liu,Yi Jiang,Shuxin Tan,Chenchen Qu,Xiuli Hao,Peng Cai,Qiaoyun Huang,Wenli Chen
Soil mineral properties significantly influence the mobility of Cd(II) within the soil matrix. However, the limited understanding of how microbial metabolism affects mineral structure at the microscale poses challenges for in situ remediation. Here, we designed a model calcium-phosphate system in a urea-rich environment to explore the impact of different microbial activation levels on Cd(II) fixation at mineral interfaces. Findings indicate that bacteria affected the morphological structure of the minerals and the amount of carbonate incorporation (average 5.4 %), thereby enhancing Cd(II) immobilization capacity (up to 9.6 times). This process is influenced by the intensity of bacterial activation, as reflected in their urease activity. Extracellular substances secreted by bacteria are also essential for activating minerals, contributing to a sustained decrease in their surface potential. The introduction of activated minerals in potting experiments markedly stimulated the soil urease activity, promoting the enrichment of functional bacteria and facilitating Cd(II) passivation, thereby reducing Cd(II) uptake by vegetables. An extensive soil survey further corroborated a linkage between soil total phosphorus and urease activity, indirectly emphasizing the universality of phosphate mineral-urease microbial interactions and their critical role in the morphological transformation of Cd(II). Our findings highlight the functional dynamics of urease microorganisms in shaping soil mineral landscapes and regulating heavy metal mobility, with broad implications for soil microscale remediation strategies.
研究领域:
环境科学
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微生物学
·
土壤学
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产品关联
DOI
PubMed
高影响因子
TALANTA
·
2021
·
IF 6.057
Jinying Liu,Jiabao Zhang,Yue Zhang,Yan Wang,Mengke Wang,Ziwen Li,Guannan Wang,Xingguang Su
In this paper, we proposed a dual-signal fluorometric and colorimetric system based on silicon quantum dots (SiQDs) and 4-nitrophenol (4-NP) for pH and urease sensing. SiQDs with fluorescence emission of 460 nm were prepared via aqueous-phase synthesis. As the pH of the system gradually increased, the absorption band of 4-NP at 400 nm increased and a color reaction from colorless to yellow occurred. The absorption of 4-NP overlapped quiet well with the fluorescence excitation spectrum of SiQDs, which can effectively quench the fluorescence of SiQDs. Therefore, the change of fluorescence and absorption intensities could be used to quantify pH value. The fluorometric and colorimetric pH-sensing systems both exhibited a linear respond to pH ranging from 6.0 to 7.8 with an interval of 0.2 pH unit. Urease could specifically hydrolyze urea to generate carbon dioxide and ammonia, causing an obvious increase of the pH value. Thus, urease could also be detected quantitatively by the above dual-signal pH sensing system. The linear ranges of the fluorometric and colorimetric methods for urease detection were both 2–40 U L-1. The limits of detection were 1.67 and 1.07 U L-1, respectively. More importantly, this established dual-signal system has been successfully exploited in the detection of urease in real samples with satisfactory recoveries. Compared with other traditional single-signal assay strategies, the results obtained by dual-signal methods are more accurate and reliable.
研究领域:
分析化学
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生物化学
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纳米技术
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产品关联
DOI
PubMed
高影响因子
POWDER TECHNOLOGY
·
2021
·
IF 5.134
Yijin Fan,Yanyun Zhao,Xiangming Hu,Weimin Cheng,Xiaoling Tang,Shucang Zhu,Chunyu Song
In this study, bacterial urease activity was optimized by response surface methodology (RSM), based on carbon source, nitrogen source, inorganic salt, pH, and other conditions required for bacterial growth. This resulted in improvement of coal dust suppression ability of bacterial mineralization. RSM showed that when the concentration of sucrose, sodium chloride, and yeast extract was optimized to 8.99, 11.27, and 8.83 g·L −1 , respectively, bacterial urease activity increased by 2.60 times compared to its original activity. Microscopic scanning indicated that the optimized dust suppressant showed larger mineral size (~40 μm diameter). X-ray diffraction results showed that contained calcite and vaterite crystals exhibited larger size (639 and 454 Å) and higher crystallinity (90.30 and 94.96%). The dust suppression effect test results indicated that the sample's wind resistance was 8.88% higher than that before optimization. This study indicates that material optimization of microbial dust suppressants contributes significantly to the field of dust suppression.
研究领域:
环境科学
·
微生物学
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产品关联
DOI
高影响因子
COLLOIDS AND SURFACES B-BIOINTERFACES
·
2019
·
IF 3.973
Jun Zhao,Chun-Liu Yu,Wei Fang,Ji-Duan Lin,Guo Chen,Xiao-Qin Wang
Self-assembled polypseudorotaxanes (PPRXs) fabricated with α -cyclodextrin and poly(ethylene glycol) (PEG) or its thiolated derivatives were candidate functional materials for enzyme soft-immobilization, encapsulation and controlled-release. The study of their interaction with Jack bean urease (JBU) indicated that they inconspicuously influenced the activity and stability of JBU during long storage, up to 30 days. The macro-species were inaccessible to JBU’s active site and the steric effect might play a significant role in the stabilization of JBU, when compared with the small-molecular sulfhydryl inhibitor thioglycolic acid. Circular dichroism and fluorescence spectra analyses revealed that thiolated PEG 400 -(SH) 2 and its assembly PPRX 400 (SH) brought in perturbations to certain α -helical or β -sheet domains of JBU, making JBU’s conformation more flexible. The resulting partial unfolding of domains exposed several hydrophobic clusters and varied JBU’s surface hydrophobicity. It also rendered the chromophores more hydrophilic and more bared to the polar environment, leading to the typical bathochromic-shift and quenching in intrinsic and synchronous fluorescence spectra. Moreover, the surface hydrophobicity profile of JBU was depicted by fluorescent probe monitoring and the unique “hydrophobic cave” motif was proposed by analyzing JBU’s structural data from the Protein Data Bank. It should be pointed out that conformational variations mainly occurred at the surface region of JBU, while the buried active bi-nickel center was not markedly influenced by the macro-species. The results demonstrated that the PPRXs might act as a proper carrier for JBU encapsulation or soft-immobilization.
研究领域:
生物化学
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材料科学
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酶学
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产品关联
DOI
PubMed
高影响因子
Analytical Methods
·
2017
·Vol. 9
·期 47
·6669-6674
·
IF 1.9
Hui Huang,Jiao Li,Mengxian Liu,Zizhun Wang,Bingdi Wang,Meini Li,Yongxin Li
A novel multifunctional semiconducting polymer dot (Pdots)/pyrogallic acid (PA) system was successfully established for fluorescence sensing of urea, urease, and pesticides. The Pdots/PA system was pH controllable, emitting strong fluorescence at pH 6.0. However, in an alkaline environment, PA transformed into its quinone structure, which is an efficient fluorescence quencher, resulting in fluorescence quenching of the Pdots/PA system. Furthermore, urea was hydrolyzed in the presence of urease, releasing hydroxyl groups that transformed PA into its quinone structure, resulting in fluorescence quenching of the Pdots/PA system. Therefore, a sensitive detection method for urea and urease was developed. The limits of detection for urea and urease were 0.02 mM and 0.08 U L−1, respectively. Pesticides, such as dimethoate, were able to inhibit the urease activity, resulting in recovery of the fluorescence intensity of the Pdots/PA system. Therefore, the fluorescence turn-on detection of pesticides could be also achieved. A satisfactory result was obtained when using the system to detect pesticides in fruit and vegetable samples.
研究领域:
分析化学
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生物传感器
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环境监测
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食品安全
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分子探针
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酶学
✓ 已验证
DOI
高影响因子
Nanomaterials
·
2022
·Vol. 12
·期 22
·4023
·
IF 5.719
Yan Li,Aowei Zhao,Jieqiong Wang,Jieyu Yu,Fei Xiao,Hongcheng Sun
In this work, highly fluorescent gold nanowire arrays (Au NWs) are successfully synthesized by assembling Zn2+ions and non-emissive oligomeric gold-thiolate clusters using mercaptopropionic acid both as a reducing agent and a growth ligand. The synthesized Au NWs exhibited strong bluish green fluorescence with an absolute quantum yield up to 32% and possessed ultrasensitive pH stimuli-responsive performance in the range of 7.0–7.8. Based on the excellent properties of the as-prepared nanowire arrays, we developed a facile, sensitive, and selective fluorescent method for quantitative detection of urea and urease. The fabricated nanoprobe showed superior biosensing response characteristics with good linearities in the range of 0–100 μM for urea concentration and 0–12 U/L for urease activity. In addition, this fluorescent probe afforded relatively high sensitivity with the detection limit as low as 2.1 μM and 0.13 U/L for urea and urease, respectively. Urea in human urine and urease in human serum were detected with satisfied results, exhibiting a promising potential for biomedical application.Keywords:gold nanowire arrays;self-assembly;enhanced fluorescence;assembly induced emission;urea and urease
研究领域:
生物传感
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纳米材料
·
医学检测
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产品关联
DOI
PubMed
高影响因子
Journal of Cleaner Production
·
2021
·
IF 9.297
Huan Wang,Hui Zhang,Dagan Zhang,Jie Wang,Hui Tan,Tiantian Kong
Excessive urea causes poor stress resistance in plants as well as severe environmental issues . In this work, novel structural color hydrogel particles that can degrade and detect urea simultaneously were developed. Inverse opal hydrogel particles (IOHPs) with abundant carboxyl groups and immobilized urease were used. The particles could hydrolyze urea in a solution to determine the concentration of urea. Moreover, because the detection and elimination relied on specific enzyme catalysis and the pH responsiveness of the sensors, the particles displayed high specificity and sensitivity. When the proper ratio of crosslinker and monomer was chosen, the IOHP sensors responded to the urea solution with a concentration range of 0–30 mM and exhibited a linear range of 1–5 mM with a detection limit of 0.48 mM, which matched the actual demands. The IOHP sensors were applied to practical samples, and it was demonstrated that the recoveries reached ideal percentages of 94.7%–102%. All the results indicate that IOHP sensors are promising for opening a new route for the detection and elimination of urea.
研究领域:
生物技术
·
环境科学
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产品关联
DOI
高影响因子
JOURNAL OF INORGANIC BIOCHEMISTRY
·
2016
·
IF 3.205
Hu Wang,Tianxiang Lan,Xia Zhang,Dongmei Zhang,Caifeng Bi,Yuhua Fan
Three Ni(II) complexes with a sexidentate N 2 O 4 -donor bis-Schiff base ligand, namely Ni(C 36 H 34 N 2 O 8 )·2CH 3 OH ( 1 ), Ni(C 28 H 34 N 2 O 8 S 2 )·H 2 O ( 2 ) and Ni(C 40 H 36 N 4 O 8 )·3CH 3 OH ( 3 ) (C 36 H 34 N 2 O 8 = 1,2-bis(2-methoxy-6-formylphenoxy)ethane- l -phenylalanine; C 28 H 34 N 2 O 8 S 2 = 1,2-bis(2-methoxy-6-formylphenoxy)ethane- l -methionine; C 40 H 36 N 4 O 8 = 1,2-bis(2-methoxy-6-formylphenoxy)ethane- l -tryptophan) were synthesized and structurally characterized. Theoretical studies of the three complexes were carried out by density functional theory (DFT) Becke's three-parameter hybrid (B3LYP) method employing the 6-31G basis set. Moreover, the inhibitory activities were tested in vitro against jack bean urease . At the same time, molecular docking was investigated to determine the probable binding mode by inserting the complexes into the active site of jack bean urease. The experimental values and docking simulation exhibited that complex 3 showed strong inhibitory activity (IC 50 = 11.27 ± 2.08 μM) compared with the positive reference acetohydroxamic acid . Their structure-activity relationships were further discussed.
研究领域:
配位化学
·
计算化学
·
酶学
✓ 已验证
DOI
高影响因子
MICROCHIMICA ACTA
·
2018
·Vol. 185
·期 3
·1-8
·
IF 5.705
He Liuying,Lu Yuexiang,Wang Feiyang,Gao Xinxin,Chen Ying,Liu Yueying
The authors describe a colorimetric method for the determination of Hg 2+ ions based on the inhibition of the activity of the enzyme urease. The pH value of solution increases when urease hydrolyzes urea, which can be visualized by adding a pH indicator such as Phenol Red (PhR). Mercaptoethanol as a typical thiol is added to the system to improve selectivity because it binds metal ions and then - unlike the Hg 2+ mercaptoethanol complex - does not inhibit urease. Hence, the color of the pH indicator PhR turns from yellow to pink as the solution becomes alkaline. The Hg 2+ mercaptoethanol complex, in contrast, strongly inhibits urease and the color of the solution remains yellow. The findings were used to design a photometric assay based on the measurement of the ratio of absorptions of PhR at 558 nm and 430 nm. It has a linear response over the 25 to 40 nM Hg 2+ concentration range and a 5 nM detection limit. This is well below the guideline values of Hg 2+ specified by the US Environmental Protection Agency and the World Health Organization for drinking water (10 nM and 30 nM, respectively). The method was employed to the determination of Hg 2+ in water samples spiked with 10 nM levels of Hg 2+ where color changes still can be observed visually.
Schematic presentation of a colorimetric method for the ultrasensitive detection of Hg 2+ based on the inhibition of urease activity. Mercaptoethanol is used to improve the selectivity. Even at Hg 2+ concentrations as low as 5 nM, the color change still can be easily observed by bare eyes.
研究领域:
分析化学
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环境科学
·
生物化学
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DOI
PubMed
高影响因子
MICROCHEMICAL JOURNAL
·
2025
·
IF 5.1
Rong Wang,Yunqian Qin,Dan Zhao,Xinyu Yang,Xincai Xiao
Fluorescent colorimetric dual-mode pH-sensitive probes based on functional carbon dots (CDs) have significant potential in biological enzyme sensing and pathogen detection. Herein, we report the synthesis of pH-sensitive functional carbon dots (Cu-CDs) via a one-step hydrothermal method using 2,5-diaminobenzenesulfonic acid, 2,4-dihydroxybenzoic acid, and CuCl₂ as precursors. Under acidic conditions, the Cu-CDs exhibit optimal excitation and emission wavelengths at 400 nm and 540 nm, respectively. In alkaline environments, these wavelengths shift to 510 nm and 589 nm. Within the pH range of 5–8, the fluorescence color transitions from yellow to red, with the fluorescence intensity ratio (F₅₈₉/F₅₄₀) displaying a strong linear correlation. At higher concentrations, the solution undergoes a visible color change from yellow to red, accompanied by a red shift in UV–Vis absorption from 360 nm to 490 nm. Leveraging urease's ability to hydrolyze urea into CO₂ and NH₃—thereby increasing the solution's pH—a simple, rapid, and visual method for urease detection was developed using Cu-CDs as a fluorescent colorimetric probe. The method demonstrated a detection range of 1–80 U/L with a limit of detection (LOD) of 0.27 U/L. Furthermore, as Proteus bacteria naturally produce urease, Cu-CDs were successfully applied for their specific detection, achieving a detection range of 5.6 × 10 2 –1.6 × 10 5 CFU/mL and an LOD of 5.6 × 10 2 CFU/mL. This work presents a novel strategy for the rapid, direct, and visual detection of urease and Proteus bacteria.
研究领域:
分析化学
·
生物传感
·
纳米技术
·
荧光光谱学
·
细菌检测
✓ 已验证
产品关联
DOI
高影响因子
危险品化学品经营许可证（带存储）