Recent developments in urea biosensors

Dhawan, Gunjan; Sumana, Gajjala; Malhotra, Bansi D.

doi:10.1016/j.bej.2008.07.004

Cited by 189 publications

(122 citation statements)

References 137 publications

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“…The PPy-Urs-SCD film has superior sensitivity over the other films studied, Fig. 5(b), and has better detection limits than other sensors reported in the literature, which range from 1.0 × 10 −5 to 3.0 × 10 −1 M urea [21,22]. This is highlighted in Table 1, where the linear range, detection limit and response times are compared for different sensors.…”

Section: Sensing Studies Of the Polymer Filmsmentioning

confidence: 66%

The development of a highly sensitive urea sensor due to the formation of an inclusion complex between urea and sulfonated-β-cyclodextrin

Hamilton¹,

Breslin²

2014

Electrochimica Acta

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a b s t r a c tA highly sensitive urea sensor was developed by incorporating the urease enzyme (Urs) into a polypyrrole film (PPy) in one simple electropolymerisation step, using a sulfonated-␤-cyclodextrin dopant. This PPyUrs-SCD film has a superior sensitivity of 5.79 C M −1 and detection in the region of 1.0 × 10 −10 M urea, which is greater than other urea sensors reported in the literature. This is due to the formation of an inclusion complex between urea and a sulfonated-␤-cyclodextrin host in an aqueous solution, which was established using electrochemical techniques. Cyclic voltammetry was used to investigate the effect of an excess concentration of the sulfonated-␤-cyclodextrin on the currents recorded for urea. A clear reduction in the current was observed upon the addition of the sulfonated-␤-cyclodextrin. The formation constant, K f , was computed as 2745 ± 300 M −1 , indicating the formation of a relatively strong inclusion complex. In addition, a 1:1 stoichiometry for the inclusion complex was deduced from a Job's plot analysis.

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Section: Sensing Studies Of the Polymer Filmsmentioning

confidence: 66%

The development of a highly sensitive urea sensor due to the formation of an inclusion complex between urea and sulfonated-β-cyclodextrin

Hamilton¹,

Breslin²

2014

Electrochimica Acta

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“…This paper is focused on the development of a novel urea sensor formed by the entrapment of the urease enzyme within a polypyrrole matrix. This has been carried out previously [1,21], however, poor detection limits were obtained. To further enhance the detection of urea in solution, while repelling common interferants, such as uric acid and ascorbic acid, an anionic cyclodextrin was incorporated into the polypyrrole matrix together with the urease enzyme.…”

Section: Introductionmentioning

confidence: 99%

“…If this excess nitrogen is not excreted, ammonia can build up in the body to high levels which leads to cell toxicity and eventually to death [1]. The normal blood levels of urea range from 2.5 to 7.5 mM, depending on the build and relative health of the body [1]. Above 7.5 mM, the patient is said to be suffering from renal deficiency, and the kidneys fail to excrete the excess nitrogen successfully.…”

Section: Introductionmentioning

confidence: 99%

“…In addition, a small amount of urea is also excreted via sweat/perspiration, along with salts and water. If this excess nitrogen is not excreted, ammonia can build up in the body to high levels which leads to cell toxicity and eventually to death [1]. The normal blood levels of urea range from 2.5 to 7.5 mM, depending on the build and relative health of the body [1].…”

Section: Introductionmentioning

confidence: 99%

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The development of a novel urea sensor using polypyrrole

Hamilton

Breslin

2014

Electrochimica Acta

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a b s t r a c tThe urease enzyme (Urs) was successfully incorporated into a polypyrrole film (PPy) in one simple electropolymerisation step. The films were formed using different dopant anions. The polypyrrole-urease-chloride film (PPy-Urs-Cl) was deposited from a simple chloride dopant, and the polypyrrole-urease-sulfonated-␤-cyclodextrin (PPy-Urs-SCD) was formed using a sulfonated-␤-cyclodextrin (SCD) dopant. The presence of the Urs within the polymer film was evident from the fibrous morphology, observed in the SEM micrographs, and the presence of nickel, arising from the active site of the urease enzyme. The sensing ability of the films and their enzyme-free counterparts (i.e., PPy-Cl and PPy-SCD) towards urea was investigated. The dopant anion plays an important role in the sensitivity of the polymer films towards urea. The PPy-Urs-SCD film has a superior sensitivity of 5.79 C M −1 compared to 0.76 C M −1 for the PPy-Urs-Cl polymer film. Furthermore, the negative groups on the SCD eliminate interference from common interfering compounds, such as ascorbic acid.

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“…Keywords: urea; derivatization; liquid chromatography; milk; blood plasma; urine tant and frequently requested task in clinical laboratories (Czauderna and Kowalczyk, 2009;Dhawan et al, 2009). Moreover, milk urea nitrogen can be a practical bioindicator of protein utilization by lactating cows in dairy cattle nutrition programs (Petersom et al, 2004).…”

mentioning

confidence: 99%

Simple, selective, and sensitive measurement of urea in body fluids of mammals by reversed-phase ultra-fast liquid chromatography

Czauderna¹,

Kowalczyk²

2012

CZECH J ANIM SCI

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Ultra-fast liquid chromatography with a photodiode array detector for simple and rapid determination of urea in body fluids of farm animals is described. Blood plasma, milk, and urine samples are treated with trichloroacetic acid and then centrifuged. Supernatants are derivatized at room temperature using p-dimethylaminobenzaldehyde. Samples are separated using a ternary gradient of methanol in buffer and water. Derivatized urea in standards and biological samples is analyzed using a Phenomenex C18-column (Synergi 2.5 µm, Hydro-RP, 100Å, 100 × 2 mm). The photodiode detector is set to 370 and/or 254 nm for detection. Temperature is maintained at 27°C by a column heater. Clear separation of derivatized urea from the endogenous species present in assayed biological samples was achieved in less than 6 min. The urea adduct peak eluted at 4.36 ± 0.05 min. Average recoveries of the urea standards added to assayed biological materials were satisfactory (i.e. 100.2 ± 4.1%). Our chromatographic method with photodiode detection at 370 nm and at 254 nm, in particular, offers low detection (LD) and quantification limits (LQ) (370nmLD = 0.47 ng, 254nmLD = 0.027 ng and 370nmLQ = 1.41 ng, 254nmLQ = 0.080 ng, respectively). Our liquid chromato-graphy based on detection at 370 nm is the most versatile analytical tool that assures sensitive, accurate, and precise analysis of urea in urine, milk, and plasma samples, and selected diets for mammals. The presented chromatographic procedure is especially suitable for preparation of reference sample sets, very accurate and precise research purposes or rapid clinical diagnostic with smaller sample sets. Urea in urine can be also determined using our liquid chromatography with detection at 254 nm. Detection of urine urea at 254 nm is more sensitive and precise compared with monitoring at 370 nm. Our chromatographic method based on photodiode detection at 370 nm and especially at 254 nm is suitable for the non-invasive analysis of urea in only urine of humans and animals.

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Recent developments in urea biosensors

Cited by 189 publications

References 137 publications

The development of a highly sensitive urea sensor due to the formation of an inclusion complex between urea and sulfonated-β-cyclodextrin

The development of a highly sensitive urea sensor due to the formation of an inclusion complex between urea and sulfonated-β-cyclodextrin

The development of a novel urea sensor using polypyrrole

Simple, selective, and sensitive measurement of urea in body fluids of mammals by reversed-phase ultra-fast liquid chromatography

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