Sensitive Detection Of Chloramphenicol Research Articles

Point-of-care monitoring of milk quality by rapid Immunofluorescence with mechanical deformation of the hydrogel microspheres

Point-of-care testing (POCT) of chloramphenicol (CAP) in fresh milk from private ranches is essential to ensure food safety. It’s still a great challenge to meet simultaneously rapid and accurate during POCT of CAP. Here, we present a POCT device integrating hydrogel microsphere immunoassay and smartphone Fourier analysis for fast and sensitive detection of CAP. Based on the excellent biocompatibility and outstanding mechanical properties of hydrogel microspheres (100 μm), the antibody activity can be maintained and the mechanical deformation of the hydrogel cross-linking lattice is induced by squeezing to accelerate the antigen-antibody reaction of CAP and anti-CAP antibodies. The signal-to-noise ratio of the detection result is optimized adaptively by a designed microsphere Fourier analysis algorithm for precise CAP concentration detection. The results show that the method decreases incubation time from 60 min to 25 min and meets detection limit requirements of industrial production (0.05 ng/mL, with a dynamic range of 0.05–8 ng/mL). This method not only achieves rapid and accurate on-site detection of CAP in milk but also applies to other low concentrations of harmful substances detection in food field.

Well-ordered Au@Ag NBPs/SiO2 nanoarray for sensitive detection of chloramphenicol via DNAzyme-assisted SERS sensing

Misuse of chloramphenicol (CAP) can lead to severe food safety issues. Therefore, the accurate and sensitive detection of CAP residues is important for public health. Herein, a convenient and reliable interfacial self-assembly technique was used to form a uniform Au@Ag nanobipyramids (NBPs) film on an ordered SiO2 nanosphere array (SiO2 NS), which served as a Raman-enhanced substrate. In conjunction with a deoxyribonucleic acid enzyme–induced signal amplification strategy, we developed a novel surface-enhanced Raman scattering (SERS) biosensor for the selective and sensitive detection of CAP. The biosensor exhibited a detection limit of 6.42 × 10−13 mol·L−1 and a detection range of 1.0 × 10−12–1.0 × 10−6 mol·L−1. The biosensor could detect CAP in spiked milk samples with a high accuracy, and its recovery rates ranged from 97.88% to 107.86%. The as-developed biosensor with the advantages of high sensitivity and high selectivity offers a new strategy for the rapid, reliable and sensitive detection of CAP, rendering it applicable to food safety control.

Carbon-dots encapsulated luminescent metal–organic frameworks@surface molecularly imprinted polymer: A facile fluorescent probe for the determination of chloramphenicol

In this study, carbon dots (CDs)-encapsulated luminescent metal–organic frameworks@surface molecularly imprinted polymer (CDs@MOF@SMIP) was facilely prepared and applied as fluorescent probe for specific identification and sensitive detection of chloramphenicol (CAP) in food. Fluorescent CDs, serving as signal tags, were encapsulated within metal–organic backbones (ZIF-8), yielding luminescent MOF materials (CDs@ZIF-8). The synthesized CDs, CDs@ZIF-8 and CDs@ZIF-8@SMIP were investigated by morphological and structural characterizations (UV–Vis, XRD, FT-IR, BET, TEM). The CDs@ZIF-8@SMIP probe was demonstrated to have remarkable selectivity and sensitivity towards CAP. Its fluorescence decreased linearly with CAP concentration from 0.323 μg L-1 (0.001 μM) to 8075.0 μg L-1 (25.0 μM), featuring a low detection limit of 0.08 μg L-1. The CDs@ZIF-8@SMIP-based fluorescence strategy achieved satisfactory recoveries (95.5 % − 101.0 %) in CAP-spiked commercial foods with RSD < 4.4 % (n = 3). These results indicate that this method can effectively detect trace CAP in food matrices and has broad application prospects.

Competitive immunoassay using enzyme-regulated Fe3O4@COF/Fe3+ fluorescence probe for natural chloramphenicol detection

Accurate and sensitive detection of chloramphenicol (CAP) in natural samples is essential for ensuring human health. Herein, an enzyme-regulated fluorescence sensor using Fe3O4@COF/Fe3+ probe, is developed for CAP determination. Fe3O4@COF, synthesized via hydrothermal method, exhibits dual functions as a magnetic carrier and signal probe. Bovine serum albumin conjugated-chloramphenicol, adsorbed on the surface of Fe3O4@COF, competes with CAP for antibody binding. The antibody interacts with alkaline phosphatase via the biotin-streptavidin system. Meanwhile, ascorbic acid, produced from the enzyme-catalyzed reaction dominated by alkaline phosphatase, effectively restores the fluorescence of Fe3O4@COF that is quenched by Fe3+. After experimental verification and gradual optimization, a logarithmic linear relationship between CAP concentration and fluorescence intensity is established in the range of 2 × 10−4∼10 μg mL−1, with a good limit of detection (9.2 × 10−5 μg mL−1). Proposed method exhibits excellent stability (15 days) and reusability (8 cycles), providing a sensitive and reliable method for accurate CAP detection. The readouts show good agreement with HPLC and recoveries during laboratory and natural CAP analysis.

Sensitive detection of chloramphenicol and efficient adsorbent for conge red of lanthanide complexes based on lactam carboxylic acid ligands

Two lanthanide metal complexes [M(H4L)Cl(OH) (H2O)2]n [M = La (1), Ce (2)] were constructed via lactam carboxylic acid ligand (2-(5-amino-2,5-dihydro-1H-imidazole-4-yl)-4-oxo-3,4-dihydroquinazoline-7-carboxylic acid) (H5L) under solvothermal condition. Complexes 1 and 2 could sensitively, selectively and repeatedly detect chloramphenicol (CAP) through the fluorescence quenching effect with a quenching constant (Ksv) of 1.87 × 103 and 1.52 × 104 Μ−1, respectively, and the detection limit (LOD) were 1.23 × 10−6 and 2.03 × 10−7 M, respectively. Density functional theory (DFT) calculations indicate that the LUMO energy level of the CAP quenched was lower than that of the ligand, so the photoelectron energy transfer (PET) between complexes and CAP leads to fluorescence quenching. Moreover, 1 and 2 exhibited excellent adsorption performance to Congo red (CR) and adsorption capacity were 3448.3 mg g−1 and 1886.5 mg g−1, respectively. Adsorption kinetics experiments showed that this kind of adsorption belonged to chemisorption, the hydrogen bonding and π-π interactions between the complex host and CR guest molecules resulted in high adsorption capacity.

Toward a comprehensive understanding of effect of cation distribution and M2+ constituent in spinel ferrite nanocrystals MFe2O4 (M = Co, Mn, and Ni) on the electrochemical response in sensitive detection of chloramphenicol

This paper focuses on investigating the effect of the (M2+) cation constituent and the inverse degree within the lattice structure of MFe2O4 (M = Co, Mn, and Ni) nanocrystals on their electrochemical characteristics and sensing performance under the same experimental condition. Using Rietveld refinement of powder X-ray diffraction (XRD), Raman, and scanning electron microscopy (SEM), physical characterizations of CoFe2O4 (CFO), MnFe2O4 (MFO), and NiFe2O4 (NFO) are observed and analyzed. In particular, a detailed study on current response and kinetic parameters for the electron transfer reactions in the presence of K3/K4 probes and chloramphenicol (CAP) analyte is carried out, respectively, highlighting the positive influence of the electrode modification and comparing the electrochemical characteristics and sensing performance. The ordering of their electrochemical performance is listed as follows: CFO/SPE> NFO/SPE> MFO/SPE. The reason for their electrochemical performance difference is discussed in detail. Namely, the CFO sample possessing high crystallization and phase purity, uniform primary particle size, and especially wholly inversed spinel structure possessing multiple valence states (Co2+ and Co3+) on the octahedral sites offered many unique features, which are beneficial for electrical conductivity, charge transferability, surface area, and electrocatalytic active sites. Despite also being the inversed spinel structure, the NFO with the existence of impurity phases and larger grain size, as well as a lower degree of inversion than the CFO sample showed a lower enhancement in electrochemical response. However, its electrochemical signal response still is higher than that of the normal spinel MFO structure, further confirming the critical role of (M2+) cation constituent and the inverse degree to the electrochemical characteristics and sensing performance.

Polydopamine-mediated quantity-based magnetic relaxation sensing for the rapid and sensitive detection of chloramphenicol in fish samples

Chloramphenicol is an antibiotic that cause adverse effects in humans. In this work, a novel quantity-based magnetic relaxation switching (sMRS) sensor using polydopamine (PDA) for signal amplification was successfully developed for the rapid and sensitive detection of chloramphenicol in fish samples. We first prepared the conjugation of large magnetic nanoparticles (MNPs) and CAP antigen (MNP-antigen), which performed a competitive immune reaction with chloramphenicol and chloramphenicol antibody. Horseradish peroxidase, that can bind to antibody at the surface of large MNPs, was employed to catalyze the rapid polymerization of dopamine to PDA, which was easily deposited onto the surface of large MNPs. The concentration of chloramphenicol is inversely proportional to the content of HRP after reaction, in other words, it is inversely proportional to the content of PDA. PDA then reacted with 30 nm-diameter amine-functionalized MNPs (NH2-MNP30), the consumption of which resulted in a decrease in the concentration of free NH2-MNP30 particles in solution. After magnetic separation, the remaining free NH2-MNP30 served as the magnetic probe for signal readout. The limit of detection of the sMRS assay for detecting chloramphenicol was 16.6 pg/mL, which was 49-fold lower than MRS sensor without signal amplification. This quantity-based MRS sensor can provide a powerful platform for enabling the rapid and sensitive detection of chloramphenicol in food samples.

A visual on-site biosensor for low-cost detection of chloramphenicol based on aptamer and split DNAzyme.

Chloramphenicol (CAP) is a kind of broad-spectrum antibiotic, which has been forbidden in food by most countries because of its side effects. In this study, a simple and low-cost biosensor for CAP detection in food was developed. The biosensor consisted of an aptamer specific to CAP and a pair of split probes that could self-assemble as DNAzyme. The detection result could be identified by the naked eye and the visual limit was 10nM CAP. The absorbance of final reaction products at 417nm had a linear relationship with the logarithm of the CAP concentration in a range from 10 to 200nM, and the limit of detection was 87.3pM. The visual analysis by imageJ also showed a linear detection range between 25 and 200nM. The entire detection procedure could be completed in about 1.5h at a cost of about 0.16 dollars per reaction. We believe that the biosensor shows great potential in the rapid and sensitive detection of CAP in food.

Toward a Comprehensive Understanding of Effect of Cation Distribution and M2+ Constituent in Spinel Ferrite Nanocrystals Mfe2o4 (M = Co, Mn, and Ni) on the Electrochemical Response in Sensitive Detection of Chloramphenicol

Toward a Comprehensive Understanding of Effect of Cation Distribution and M2+ Constituent in Spinel Ferrite Nanocrystals Mfe2o4 (M = Co, Mn, and Ni) on the Electrochemical Response in Sensitive Detection of Chloramphenicol

Label free structure-switching fluorescence polarization detection of chloramphenicol with truncated aptamer

In this study, the original chloramphenicol aptamer containing 80 bases was truncated to 30 bases with high affinity by the SYBR Green I assay. It was found that the ionic strength and type affect the recognition of aptamers, especially magnesium ion played a vital role in the binding process. Furthermore, the binding performance of aptamer, including binding mode, key binding sites and conformational changes were further investigated by circular dichroism spectroscopy, UV–vis absorption spectrum and molecular docking. Based on these research data, we inferred that chloramphenicol bound to the minor groove region in the aptamer double helix. Finally, the optimized aptamer LLR10 was used to develop a novel label free fluorescence polarization assay to detect chloramphenicol within SYBR Green I as the source of fluorescence polarization signal. Under optimal conditions, the designed method showed a linear detection range of 0.1–10 nM with a detection limit of 0.06 nM. Additionally, the aptasensor exhibited a high accuracy to the detection of chloramphenicol in milk samples with a recovery rate from 93.7% to 98.4%. Therefore, the developed label free fluorescence polarization aptasensor provides a new idea for the rapid, reliable and sensitive detection of chloramphenicol, which can be applied to food safety control.

Improved conductivity of flower-like MnWO4 on defect engineered graphitic carbon nitride as an efficient electrocatalyst for ultrasensitive sensing of chloramphenicol

Environmental hazards caused by chloramphenicol has attained special attention. Fast, accurate and reliable detection of chloramphenicol in foodstuffs and water samples is of utmost importance. Herein, we developed a g-C3N4/MnWO4 composite for the selective and sensitive detection of chloramphenicol. Successful fabrication of g-C3N4/MnWO4 composite was verified by using scanning electron microscopy (SEM), transmission electron microscopy (TEM), Raman spectroscopy, Fourier transform infrared spectroscopy (FT-IR), x-ray diffraction (XRD) and x-ray photo electron spectroscopy (XPS) techniques. Electrochemical characteristics were evaluated by using cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS) and differential pulse voltammetry (DPV). The g-C3N4/MnWO4 modified glassy carbon electrode has shown the highest electrocatalytic activity towards chloramphenicol with a decreased reduction potential of -0.547 V and increased cathodic peak current. The developed sensor has shown excellent performance for the detection of chloramphenicol with a sensitivity of 0.9986 μA nM−1 cm−2 and LOD of 1.03 nM in a broad linear range of 4.0–71 nM. In addition, the fabricated sensor has achieved anti-interference ability, good stability, excellent repeatability and remarkable reproducibility for the detection of chloramphenicol. The fabricated sensor applied for the determination of chloramphenicol in milk, human blood serum and sewage samples, in which significant and satisfactory results were achieved.

Sensitive and rapid aptasensing of chloramphenicol by colorimetric signal transduction with a DNAzyme-functionalized gold nanoprobe

By combination of the aptamer biorecognition with the colorimetric signal transduction of a DNAzyme-functionalized nanoprobe, a new biosensing method was developed for the rapid and sensitive detection of chloramphenicol (CAP). The nanoprobe was prepared through the functionalization of gold nanoparticles with the complementary oligonucleotide against aptamer and high-content hemin/G-quadruplex DNAzyme. When one-step incubating the nanoprobe and CAP at a constructed aptamer-magnetic bead (MB) biosensing platform, due to the competitive biorecognition reaction, the nanoprobes related with CAP amounts were quantitative captured onto the MB surface. Based on the catalytic reaction of the peroxidase-mimicking DNAzyme, a colored substance was produced for the colorimetric signal transduction of the method. Due to the great signal amplification of the nanoprobe, a very low detection limit down to 0.13 pg/mL was obtained. Considering the excellent performance of the aptasensing method and satisfactory results for milk sample experiments, it indicates good reliability for practical applications.

Quantitative and Sensitive Detection of Chloramphenicol by Surface-Enhanced Raman Scattering.

We used surface-enhanced Raman scattering (SERS) for the quantitative and sensitive detection of chloramphenicol (CAP). Using 30 nm colloidal Au nanoparticles (NPs), a low detection limit for CAP of 10−8 M was obtained. The characteristic Raman peak of CAP centered at 1344 cm−1 was used for the rapid quantitative detection of CAP in three different types of CAP eye drops, and the accuracy of the measurement result was verified by high-performance liquid chromatography (HPLC). The experimental results reveal that the SERS technique based on colloidal Au NPs is accurate and sensitive, and can be used for the rapid detection of various antibiotics.

A novel biosensor based on competitive SERS immunoassay and magnetic separation for accurate and sensitive detection of chloramphenicol

The accurate and sensitive detection of chloramphenicol (CAP) is particularly imperative to public health and safety. Here, we present a novel sensor for residual CAP detection based on competitive surface-enhanced Raman scattering (SERS) immunoassay and magnetic separation. In this nanosensor, functionalized Au nanoparticles (AuNPs) were labeled with the Raman reporter molecule (e.g. 4,4′-dipyridyl). With the addition of free CAP, a competitive immune reaction was initiated between free CAP and above AuNPs for conjugating with CAP antibody-modified magnetic nanoparticles (MNPs). Instead of the solid substrate, the antibody conjugated-magnetic beads were used as supporting materials and separation tools in the present sensor. With the aid of a magnet, the mixture was removed from the supernatant for concentration effects. This caused obvious change of SERS signal intensity obtained from supernatant. The SERS signals were collected from the supernatant directly, which made the SERS measurements more stable, repeatable and reliable. The proposed SERS-based magnetic immunosensor allows us to detect CAP in a fast, selective and sensitive (1.0pg/mL) manner over a wide concentration range ( 1–1×104pg/mL). In addition, these results demonstrate that this immunosensor holds great potential for the detection of antibiotics in real aquatic environment, which is crucial to our life.

Surface plasmon resonance assay for chloramphenicol without surface regeneration

A surface plasmon resonance (SPR) assay without surface regeneration was developed for rapid and sensitive detection of chloramphenicol (CAP). A CAP–amine derivative was synthesized using a polyethylene glycol chain attached to the CAP through a carbamate linkage and immobilized onto a Biacore dextran surface. This chemically modified surface significantly changed the binding behavior between antibody and CAP, shown by both fast association and fast dissociation rates, and created a rapid and sensitive SPR immunoassay of the CAP without any regeneration. The limits of detection achieved for CAP were 32.2 pg/ml in aqueous buffer and 42.4 pg/ml in honey-spiked samples.