Selective Detection Of Uric Acid Research Articles

Photosensitized covalent organic framework as a light‐induced oxidase mimic for colorimetric detection of uric acid

AbstractAs large numbers of people are suffering from gout, an accurate, rapid, and sensitive method for the detection of gout biomarker, uric acid, is important for its effective control, diagnosis, and therapy. Although colorimetric detection methods based on uricase have been considered, they still have limitations as they produce toxic H2O2 and are expensive and not stable. Here, a novel uricase‐free colorimetric method was developed for the sensitive and selective detection of uric acid based on the light‐induced oxidase‐mimicking activity of a new photosensitized covalent organic framework (COF) (2,4,6‐trimethylpyridine‐3,5‐dicarbonitrile–4‐[2‐(4‐formylphenyl)ethynyl]benzaldehyde COF [DCTP–EDA COF]). DCTP–EDA COF has a strong ability to harvest visible light, and it could catalyze the oxidation of 1,4‐dioxane, 3,3′,5,5′‐tetramethylbenzidine under visible light irradiation to produce obvious color changes. With the addition of uric acid, however, the significant inhibition of the oxidase‐mimicking activity of DCTP–EDA COF remarkably faded the color, and thus uric acid could be colorimetrically detected in the range of 2.0–150 μM with a limit of detection of 0.62 μM (3σ/K). Moreover, the present colorimetric method exhibited high selectivity; uric acid level in serum samples was successfully determined, and the recoveries ranged from 96.5% to 105.64%, suggesting the high accuracy of the present colorimetric method, which demonstrates great promise in clinical analysis.

Ultraflexible polyvinylidene fluoride film based amperometric enzyme-free sensor for selective detection of uric acid in a trace level.

The present invention describes a novel flexible nanosensor for the electrochemical detection of uric acid (UA) present in urine. The synthesized graphite-boron nanocomposite with an average thickness of ∼32 nm was grown up on a flexible polyvinylidene fluoride film with an average thickness of ∼50 μm and it acts as a nonenzymatic sensor for UA. The developed flexible sensor showed a prominent reduction peak in cyclic voltammetry and amperometric response with the presence of different concentrations of aqueous UA solution. In the electrochemical study, the redox peak was generated near ∼-0.42 V with a detection limit of around ∼2.09 μM as the bottom level. The high robustness of the developed sensor originated from the polymeric film base and the rapid response time of ∼0.5 s for detecting UA present in human urine. The interference property of the sensor was confirmed in the presence of bilirubin and creatinine as an eventual reference toward selectivity. The phase and morphology of the sensor surface were extensively observed before and after sensing to comprehend the electrochemical interaction between the sensor and target molecules. The generated quantitative results of the integrated system were verified by testing known and unknown concentrations of UA solutions.

Nonenzymatic Sweat Wearable Uric Acid Sensor Based on N-Doped Reduced Graphene Oxide/Au Dual Aerogels.

Sweat wearable sensors enable noninvasive and real-time metabolite monitoring in human health management but lack accuracy and wearable applicability. The rational design of sensing electrode materials will be critical yet challenging. Herein, we report a dual aerogel-based nonenzymatic wearable sensor for the sensitive and selective detection of uric acid (UA) in human sweat. The three-dimensional porous dual-structural aerogels composed of Au nanowires and N-doped graphene nanosheets (noted as N-rGO/Au DAs) provide a large active surface, abundant access to the target, rapid electron transfer pathways, and a high intrinsic activity. Thus, a direct UA electro-oxidation is demonstrated at the N-rGO/Au DAs with a much higher activity than those at the individual gels (i.e., Au and N-rGO). Moreover, the resulting sensing chip displays high performance with a good anti-interfering ability, long-term stability, and excellent flexibility toward the UA detection. With the assistance of a wireless circuit, a wearable sensor is successfully applied in the real-time UA monitoring on human skin. The obtained result is comparable to that evaluated by high-performance liquid chromatography. This dual aerogel-based nonenzymatic biosensing platform not only holds considerable promise for the reliable sweat metabolite monitoring but also opens an avenue for metal-based aerogels as flexible electrodes in wearable sensing.

Cesium lead bromide as a colorimetric and fluorometric sensing platform for the selective detection of uric acid

In this work, a simple and sensitive colorimetric fluorescence sensing probe was designed for the detection of uric acid (UA).

Spontaneous immobilization of thiocyanate onto Au surface for the detection of uric acid in basic medium

Uric acid (UA), a biologically important chemical, exhibits detrimental environmental impacts on farmland as well as groundwater following irrational usage and maintenance. It is well known that determining the concentration of pollutants is the first step to control environmental pollution. Concerning this fact, a compact thiocyanate (SCN) adlayer based Au electrode was fabricated by a spontaneous immobilization of SCN- ions on a polycrystalline Au surface pertaining to the selective detection of uric acid in a basic medium. The formed adlayer completely shielded the Au surface from routine passivation by uric acid species or its products, preventing electrode fouling. To verify the morphology of the electrode surface, cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS), X-ray photoelectron spectroscopy (XPS), and linear polarization techniques were used. Voltammetric diagnosis revealed that the UA oxidation reaction on the SCN-adlayer based Au electrode basically follows first-order kinetics with a stepped mechanistic approach where one electron transfer is engaged in the rate-determining steps. On top of that, the limit of detection and the sensitivity were estimated to be 0.25 µM and 0.199 mA cm−2 mM−1, respectively. Interference studies also ascertain the fact that the proposed electrode is reasonably selective in the presence of cohabiting ionic species. Therefore, the developed sensor can be used in the analytical detection of UA in real samples.

A cost-effective disposable graphene-based sensor for sensitive and selective detection of uric acid in human urine

A rapid and facile method has been developed for uric acid (UA) sensing in human urine. The graphite pencil electrode's (GPE) sensitivity and electrochemical activity for sensing uric acid in human urine were enhanced by the electrochemically reduced graphene oxide on GPE in acetate buffer (ac-dERGO-GPE). Acetate, medium-supported graphene oxide reduction, is more facile, fast, and sensitive than water-dispersed graphene oxide. The surface of the modified and bare electrode was thoroughly investigated using the Fourier transform-infrared (FTIR), Field emission-scanning electron microscopy (FE-SEM), cyclic voltammetry (CV), square wave voltammetry (SWV), and electrochemical impedance spectroscopy (EIS). The electroactive surface area of the modified electrode was significantly improved from 0.0686 cm2 to 0.3615 cm2. The graphene layers greatly enhanced the electroactive surface area and the sensitivity of the ac-dERGO/GPE. A linear response was observed for UA in the range of 0.200 μM–22.0 μM with a 0.996 regression coefficient and a low detection limit of 0.037 μM. The modified electrode retained its response intact in the presence of the potential interferences and successfully applied for UA sensing in human urine. The ac-dERGO/GPE sensor, due to its facile fabrication, low cost, excellent sensitivity, and high selectivity could be a potential candidate for trace level quantification of uric acid in human urine.

Liquid crystal-based sensitive and selective detection of uric acid and uricase in body fluids

The abnormal levels of uric acid (UA) in body fluids are associated with gout, type (II) diabetes, leukemia, Lesch-Nyhan syndrome, uremia, kidney damage, and cardiovascular diseases. Also, the presence of uricase (UOx) symbolizes genetic disorders and corresponding complications. Therefore, the detection of UA and UOx in the body fluids is significant for clinical diagnosis. 4-Cyano-4′-pentylbiphenyl (5CB, a nematic liquid crystal (LC)) was doped with octadecyl trimethylammonium bromide (OTAB, a cationic surfactant), which formed a self-assembled monolayer at the aqueous/5CB interface. The UOx-catalyzed oxidation of UA yielded H2O2, releasing the single-strand deoxyribonucleic acid (ssDNA) from the nanoceria/ssDNA complex. The interaction of the released ssDNA with OTAB disrupted the monolayer at the aqueous/5CB interface, which resulted in a dark to bright change when observed through a polarized optical microscope. The LC-based sensor allowed the detection of UA with a linear range of 0.01–10 μM and a limit of detection (LOD) of 0.001 μM. The UA detection was also performed in human urine samples and the results were comparable to that of a standard commercial colorimetric method. Similarly, the detection of UOx was performed, with a noted linear range of 20–140 μg/mL. The LOD was as low as 0.34 μg/mL. The detection of UOx was also demonstrated in human serum samples with excellent performance. This method provides a robust sensing platform for the detection of UA and UOx and has potential for applications in clinical analysis.

A Cost-Effective Disposable Graphene-Based Sensor for Sensitive and Selective Detection of Uric Acid in Human Urine

A Cost-Effective Disposable Graphene-Based Sensor for Sensitive and Selective Detection of Uric Acid in Human Urine

Molecularly imprinted electrochemical sensor based on electrode modified by functionalized carbon nanotube for selective detection of uric acid

In this study, we have developed a novel biomimetic electrochemical sensor sensitized with functionalized carbon nanotubes using a molecularly imprinted film as a recognition element for the rapid detection of uric acid. Using K 3 [Fe(CN) 6 ] as a probe, uric acid imprinted films on electrodes are characterized by voltammetry measurements and electrochemical impedance spectroscopy. The optimizations of experimental steps are conducted by cyclic voltammetry and differential pulse voltammetry. When the imprinted sensor is immersed in the solution containing a certain concentration of uric acid and incubated for a period of time, the oxidation peak current of K 3 [Fe(CN) 6 ] decreases with the increase of uric acid concentration. Under optimal conditions, the peak current of K 3 [Fe(CN) 6 ] has a good linear relationship with uric acid concentration at range from 0.1 μM to 3.3 μM with the detection limit of 0.03 μM. The proposed sensor shows high selectivity for rapid detection of uric acid in human serum samples.

Electrochemical synthesis of composite materials based on titanium carbide and titanium dioxide with poly(N-phenyl-o-phenylenediamine) for selective detection of uric acid

• TiC/TiO 2 -polymer composites synthesis by electrochemical methods in one step. • Tunable electrocatalytic activity towards ascorbic and uric oxidation. • Selective detection of uric acid in presence of ascorbic acid with no interference effects. Synthesis of electrode materials for accurate detection and quantification of uric acid without the interference effect of ascorbic acid is still considered an important field for health monitoring in human beings. As we present here, a methodology of composite materials synthesis have been developed to obtain electroactive materials, employing electrochemical methods in a single step based on titanium carbide and titanium dioxide entrapped into a polymer matrix of poly( N -phenyl- o -phenylenediamine). The presence of the TiC and TiO 2 nanoparticles entrapped into the polymer matrix has provided enhancement in the conductivity, electron transfer kinetics and electrochemical activity towards uric acid oxidation. The electrochemical behavior of the composite materials towards ascorbic and uric acid oxidation demonstrated that electrochemical oxidation of uric acid has not been affected by the presence of ascorbic acid in solution, being a suitable platform for non-invasive detection and quantification of uric acid concentration in physiological samples without the interference of ascorbic acid.

Heteroatom-Doped Carbon Nanoparticle–Ionic Liquid Composites as Electrochemical Sensors for Uric Acid

We reported the fabrication of an electrochemical sensor for uric acid (UA) monitoring using metal-free electrode based on heteroatoms (S, N, P, and O) doped carbon (HADC) nanoparticles, derived from polyphosphazene, synthesized via precipitation polymerization reaction between hexachlorocyclotriphosphazene (HCCP) and 1,4-dithiane-2,5-diol (DD) under sonication irradiations at 40 °C, following its modification with benzimidazolium-1-acetate ionic liquid (BIL). The developed HADC-BIL electrode showed a highly sensitive and selective response toward UA even in the presence of highly electroactive interferences such as ascorbic acid (AA), dopamine (DA), glucose (Glu), and hydrogen peroxide (H2O2). Our results demonstrated that the as-fabricated HADC-BIL electrode allows us to detect UA over a linear range of 2–1050 μM with a detection limit of 1.27 μM. Further, we were able to monitor the amount of UA level in the blood of a gout patient using the developed HADC-BIL electrode, which ensures the effectiveness of the developed sensor for the sensitive and selective detection of UA from real samples.

Non-Enzymatic Electrochemical Detection for Uric Acid Based on a Glassy Carbon Electrode Modified With MOF-71

The development of non-noble-metal sensing material for sensitive and selective detection of uric acid with a simple material synthesis technique has not been frequently reported in recent years. Taking advantage of the unique properties of highly porous materials of Metal-Organic Frameworks, which incomparable in their structural diversity and tunability as well as their range of chemical and physical properties, open up a chance for developing novel nanomaterial for electrochemical sensor applications. In this article, we evaluated MOF-71 as a sensing material on a glassy carbon electrode (GCE) in a three-electrode system for electrochemical detection of uric acid. The MOF-71 was synthesized by a simple solvothermal method. Its structural characteristics that are examined by scanning electron microscopy and X-ray diffraction confirmed the successful formation of MOF-71. Cyclic voltammetry (CV) and differential pulse voltammetry DPV) analysis showed the successful uric acid detection in a phosphate buffer solution and showed good electrochemicalcatalytic activity toward uric acid. DPV was selected for the determination of uric acid with a sensitivity of 0.4811 mA.mM <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">-1.</sup> cm <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">-2</sup> , the detection range of 50.0-1000 μM, and detection limit of 15.61 μM at an S/N = 3.

One-step hydrothermal synthesis of silver-doped carbon quantum dots for highly selective detection of uric acid

In this paper, a simple and convenient fluorescence method for detection of uric acid (UA) based on Ag–doped carbon quantum dots (Ag–CQDs) is developed. The Ag–CQDs contain Ag species could bond with UA, which promoted the electron and/or energy transfer and produced high quenching extent. Thus, the fluorescence intensity of Ag–CQDs decreased in the presence of UA. Under the optimal condition, the UA sensor exhibited a linear response in the range of 0.005–100 μM with a detection limit of 0.35 nM (S/N = 3). Ag–CQDs demonstrated high sensitivity and rapid response to UA over a wide range of concentration indicating their great potential as a fluorescent probe for chemical sensing. Moreover, this method has successfully applied to detect UA in human urine samples.

Uricase grafted nanoconducting matrix based electrochemical biosensor for ultrafast uric acid detection in human serum samples.

Gold nanoparticles decorated graphene oxide (Au-rGO) nanocomposite thin films with enhanced electro-active characteristics were prepared and covalently immobilized with uricase (UOx) enzyme for sensitive and selective detection of uric acid (UA). Differential pulse voltammetry (DPV) studies revealed rapid response of fabricated electrode towards UA at low potential (0.228 V) in a wide concentration range of 50-800 μM with a sensitivity of 86.62 ± 0.19 μA mM-1 and very low detection limit of 7.32 ± 0.21 μM. The obtained Michaelis-Menten constant (km) value of 51.75 μM signifies high enzyme kinetics at electrode surface with UA. The developed biosensor was successfully applied to detect UA in human serum samples. Interferences due to components present in the real matrix were evaluated and UA determination in mixed sample was also performed. The fabricated UOx/Au-rGO/ITO biosensor demonstrated high reproducibility and a shelf-life of 6 months indicating the promising future of Au-rGO nanocomposite as an efficient transducer matrix for biosensing applications. The fast response time (1.0 ± 0.6 s) and improved sensor performance is attributed to the synergistic electronic properties of Au-nanoparticles and rGO that provided enhanced electron transfer and high electro-active species surface coverage at Au-rGO nanocomposite.

Voltammetric Determination of Uric Acid in Clinical Serum Samples Using DMF Modified Screen Printed Carbon Electrodes

Screen printed carbon electrodes (SPCEs) provide attractive opportunity for sensitive and selective determination target analytes in clinical samples. The aim of the current work was to develop SPCEs based sensor for the determination of uric acid in clinical serum samples. The electrodes were pretreated by soaking in N,N-dimethylformamide for 5 minutes followed by drying in an oven at 100°C for 20 mins. The effect of surface pretreatment was characterized using cyclic voltammetry. The current response of uric acid detection was improved by a factor of 3.5 in differential pulse voltammetric measurement compared to unmodified electrode. Under the optimized conditions, the sensor displayed two dynamic linear ranges 5-100 μM and 100-500 μM with correlation coefficient, R2, values of 0.98782 and 0.97876, respectively. The limit of detection and limit of quantification calculated using the dynamic linear range 5-100 μM were 1.9 x 10−7 M and 6.33 x 10−7 M, respectively. The developed sensor displayed well separated and discerned peaks for UA in presence of the potential interferent (ascorbic acid and citric acid). The electrode was successfully applied for the detection of very low level of UA in clinical serum samples in a phosphate buffer solution (pH = 7). The proposed sensor showed a very high reproducibility and repeatability with the relative standard deviation of 0.9%. In conclusion, a simple and low cost sensor based on SPCEs is developed for sensitive and selective detection of uric acid in clinical samples.

A luminescent terbium metal-organic framework for highly sensitive and selective detection of uric acid in aqueous media

As the final product of purine metabolism, uric acid (UA) existing in urine and serum plays an important role in the body's metabolism, immunity and other functions. However, it is still difficult to sense UA in practice. Herein, a new terbium metal–organic framework (Me2NH2)2[Tb2(L)2]·(H2O)6 (ZJU-158-Tb, ZJU = Zhejiang University, L = 1-(3,5-dicarboxylatobenzyl)−3,5-pyrazole dicarboxylic acid)for luminescent sensing of UA was designed and synthesized. It exhibits highly sensitive and selective detection to UA in aqueous solutions with a quite low detection limit of 7 nM by a luminescence turn-down phenomenon. Furthermore, the practical test papers made by ZJU-158-Tb possess fast monitoring ability for abnormal UA levels in artificial urine and serum through distinct colour change, which could be even distinguished by the naked eye.

MoS2 based ultra-low-cost, flexible, non-enzymatic and non-invasive electrochemical sensor for highly selective detection of Uric acid in human urine samples

While all reports on electrochemical uric acid (UA) sensors are on rigid electrodes and based on either complex fabrication procedures or multiple steps based synthesis techniques, this paper is the first demonstration of a single step hydrothermally grown MoS2 on aluminium foil (Al) based flexible electrochemical sensor for non-enzymatic detection of UA. FESEM images revealed MoS2 micro-flower like structure comprising of interlaced nanosheets while chemical characterization data confirmed the successful growth of few layered (>4 layers) MoS2 on Al foil. The as-fabricated flexible sensor exhibited a limit of detection of 1.169 μM, a response time of <3 s, excellent reproducibility, selectivity towards UA over glucose, ascorbic acid and urea with a sensitivity of 98.3 ± 1 nA μM−1 (R2 = 0.999) in the dynamic range of 10–400 μM. This enhanced sensing ability can be attributed to high surface area of MoS2, more numbers of active sites resulting from large numbers of defects and edges and higher proportion of metallic 1 T phase than semiconducting 2H phase. The proposed sensor was also successfully evaluated for the detection of UA in a non-invasive sample like human urine and the data corroborates well with the UA concentration obtained from conventional biochemical tests performed in clinical laboratory. This highly sensitive, ultra-low-cost MoS2 based flexible electrochemical sensor paves way for the development of affordable lab on chip devices for a wide range of bioanalytical applications.

A novel ratiometric fluorescent probe for the detection of uric acid in human blood based on H2O2-mediated fluorescence quenching of gold/silver nanoclusters

In this work, a ratiometric fluorescent probe (RF-probe) for highly sensitive and selective detection of uric acid was reported for the first time toward H2O2 based on inner filter effect (IFE) between bimetallic gold/silver nanoclusters (Au/Ag NCs) and 2,3-diaminophenazine (DAP). For this RF-probe, uric acid was degraded to allantoin and H2O2. Upon the addition of HRP, o-phenylenediamine (OPD) could be catalytically oxidized to DAP in the presence of H2O2, then the fluorescence intensity corresponding to DAP at 580 nm increased dramatically with a fluorescence quenching of BSA-Au/Ag NCs at 690 nm, resulting in a RF-probe toward uric acid. This RF-probe allowed for the sensitive detection of uric acid in range of 5.0 × 10−6 M to 5.0 × 10−5 M with a detection limit (S/N = 3) as low as 5.1 × 10−6 M. At the same time, it has been successfully used for uric acid levels detection in human serum, and the results are consistent with those of the hospital. RF-probe built may provide a ratiometric fluorescence universal platform for detection of various species involving in the production of H2O2 in other biological systems.

Trace-level and selective detection of uric acid by a luminescent Zn (II) based 1D coordination polymer in aqueous medium

A water soluble luminescent 1D metal organic coordination polymer of Zn(II) [Zn(FDA)(2,2′-bpy)(H2O)]·2H2O (2,2′-bpy = 2,2′-bipyridine and FDA = 2,5-furandicarboxylate), 1 was successfully synthesized by solvothermal method. This crystalline compound 1 showed strong luminescence emission at 325 nm upon excitation at 290 nm in aqueous medium. The luminescence intensity was highly sensitive towards a bio-metabolized purine derivative, uric acid (UA). However, it did not show any considerable response towards structurally similar other purine derivatives like adenine (Adn), guanine (Gua) and theobromine (Tbr). The compound 1 was found to be highly selective and sensitive towards uric acid (UA) with a detection limit of 300 ppb. The sensitivity and selectivity of 1 towards UA was also investigated in the presence of several metal ions, anions and organic bio-molecules which are commonly found in human urine. The results indicated that 1 could be a potential probe for selective detection and estimation of UA in urine. The mechanism of the sensing was explained successfully and it was also supported by DFT calculation.

A CoOOH nanoflake-based light scattering probe for the simple and selective detection of uric acid in human serum

In the presence of uricase, uric acid generated H2O2, which further decomposed CoOOH nanoflakes to release Co2+, resulting in smaller nanoparticles with lower light scattering. Based on the relationship between the reduced light scattering and uric acid concentration, the simple strategy was applicable to uric acid sensing in human serum samples.