A highly sensitive dual-read assay using nitrogen-doped carbon dots for the quantitation of uric acid in human serum and urine samples

Abstract

Graphical abstract A simple dual-read assay for uric acid (UA) was developed based on a combined ratiometric fluorescent and colorimetric strategy using nitrogen-doped carbon dots (N-CDs). The biosensor relies on the oxidation of UA by uricase to produce H 2 O 2 , which was then converted to • OH radicals by I - , resulting in the oxidation of o -phenylenediamine (OPD) to 2,3-diaminophenazine (DAP). In the presence of UA, the colorless biosensor system changed to yellow. Furthermore, the presence of DAP quenched the fluorescence emission of the N-CDs at 427 nm based on the inner filter effect (IFE). With increasing UA concentrations, the fluorescence intensity of the biosensor at 427 nm decreased but increased at 580 nm, demonstrating the ratiometric response. A strong linearity was observed between the fluorescence intensity ratio of DAP to N-CDs ( I 580 / I 427 ) and the corresponding UA concentration over the range 0.5−150 μM, and a limit of detection (S/N ratio of 3) of 0.06 μM was calculated. The dual-read assay was successfully employed in the quantitation of UA in human serum and urine samples, revealing its potential for measuring UA in clinical samples. Supplementary Information The online version contains supplementary material available at 10.1007/s00604-021-04971-2.

Silver Nanoparticle-Functionalised Nitrogen-Doped Carbon Quantum Dots for the Highly Efficient Determination of Uric Acid

“…where C UA is the UA concentration, and I and I 0 (see Figure 6D) denote the fluorescence intensity of the AgNPs/N-CQDs in the presence and absence of UA, respectively. Thus, a good correlation coefficient (R 2 ) of 0.9971 was obtained in addition to a UA detection limit of 0.53 µmol/L, and the relative standard deviation (RSD, n = 5) was <1.2% at a UA concentration of 10.0 µmol/L, which is comparable with the response ranges and UA limits of detection (LODs) detected reported for previous fluorescence methods [30][31][32][33][34][35][36][37] (Table 1), thereby revealing that our probe based on AgNPs/N-CQDs exhibits an outstanding performance.…”

A facile, low-cost bimetallic iron–nickel MOF nanozyme-propelled ratiometric fluorescent sensor for highly sensitive and selective uric acid detection and its smartphone application

“…5C shows that the FI 430 /FI 565 ratio values were proportional to the logarithmic concentration of UA in the range from 0.2 μM to 200 μM and the LOD was calculated to be 24 nM, which is lower than those in most previously reported works, and the lowest among nanozyme-based ratiometric fluorescent UA sensors reported to date (Table 1). [32][33][34][45][46][47][48] The superior sensitivity can be ascribed to the synergistic effect of the highly efficient fluorescence of the MOF nanozyme and elaborate design of the tandem catalytic system. In contrast, previous works showed UA detection performed solely based on the POD-like activity of nanozymes.…”

Dual emission and its λ-ratiometric detection in analytical fluorimetry Pt. II. Exploration in sensing and imaging

“…Determination of hydrogen peroxide H 2 O 2 is of its own value as an indicator of oxidative stress, and its role can be extended as an output mediator in the essays of different metabolites being the product of their oxidation by correspondent enzymes. One of these reactions catalyzed by enzyme uricase was used for the determination of uric acid [99,100]. Selective quenching of fluorescence in designed nanocomposites provides λ-ratiometric signal.…”