Oxytetracycline In Milk Research Articles

CRISPR/Cas12a-mediated fluorescent aptasensor based on DNA walker amplification for oxytetracycline detection

Nowadays, although most oxytetracycline (OTC) are used only in animals, their leaching into the environment and residues in food lead to noticeable health problems. Fortunately, by studying the molecular dynamics of OTC aptamers and the mutations of key bases, aptamer’s base fragments involved in identifying OTC was confirmed for the first time, which provided theoretical guidance for the ingenious design of aptamer detection. Thereafter, benefiting from the amplification impact by DNA walker, the disadvantage of low efficiency caused by CRISPR/Cas12a was effectively avoided. In the established delicate aptasensing platform, small quantity of OTC promoted DNA walker to produce a massive of activators, which stimulated the trans-cleavage activity of CRISPR/Cas12a. By implying nanoclusters (NCs) with covalent organic framework (COF), the sensitive fluorescence “turn-on” method for OTC detection was realized. Under the optimum conditions, the linear range of aptasensor was 0.05-50 μM, and the detection limit was 0.041 μM. In addition, the aptasensing method can be successfully used for the quantitative detection of OTC in milk and honey samples with a recovery rate of 95.67%-104.10% and 95.33%-109.70%, implying excellent analytical performance and practical application prospect.

A dual-response ratiometric fluorescent sensor for oxytetracycline determination in milk and mutton samples

Owing to the adverse effects of oxytetracycline (OTC) residues on human health, it is of great importance to construct a rapid and effective strategy for OTC detection. Herein, we developed a dual-response fluorescence sensing platform based on molybdenum sulfide quantum dots (MoS2 QDs) and europium ions (Eu3+) for ratiometric detection of OTC. The MoS2 QDs, synthesized through an uncomplicated one-step hydrothermal approach, upon OTC integration into the MoS2 QDs/Eu3+ sensing system, exhibit a significant quenching of blue fluorescence due to the inner filter effect (IFE), simultaneously enhancing the distinct red emission of Eu3+ at 624 nm, a phenomenon attributed to the antenna effect (AE). This sensor demonstrates exceptional selectivity and sensitivity towards OTC, characterized by a linear detection range of 0.2–10 μM and a notably low detection limit of 2.21 nM. Furthermore, we achieved a visual semi-quantitative assessment of OTC through the discernible fluorescence color transition from blue to red under a 365 nm ultraviolet lamp. The practical applicability of this sensor was validated through the successful detection of OTC in milk and mutton samples, underscoring its potential as a robust tool for OTC monitoring in foodstuffs to safeguard food safety.

Fluorimetric determination of tetracycline antibiotics in animal derived foods using boron and nitrogen co-doped ceria-based nanoparticles.

Aninnovative synthesis of boron and nitrogen co-doped ceria-based nanoparticles (B/N-CeFNPs) with bright blue fluorescence emission is reportedusing the hydrothermal method. Based on the aggregation-induced emission enhancement (AIEE) effect between B/N-CeFNPs and chlortetracycline (CTC), a rapid detection method for CTC through fluorescence enhancement was developed. In addition, through the electron transfer process (ET), fluorescence resonance energy transfer (FRET) effect and static quenching between B/N-CeFNPs and oxytetracycline (OTC), a ratio fluorescence strategy for detecting OTC was generated. The fluorescence of B/N-CeFNPs at 410nm can be effectively quenched by OTC, and new fluorescence emission appears at a wavelength of 500nm. B/N-CeFNPs showed good linear responses with CTC and OTC in the range 0.1-1 µM and 1-40 µM, respectively. This system was used to simultaneously detect the CTC and OTC in milk and honey, realizing multi-residues detection of TCs in actual samples by using the same ceria-based fluorescence nanomaterial.

Construction of a molecularly imprinted fluorescent sensor based on an amphiphilic block copolymer-metal-organic framework for the detection of oxytetracycline in milk.

A metal-organic framework (MOF) is a good carrier for molecular imprinting due to its high surface area and strong adsorption capacity, but its poor dispersibility in aqueous solution is one of the significant drawbacks, which can severely impede its effectiveness. Amphiphilic block copolymers are good hydrophilic materials and have the potential to overcome the shortcomings of MOFs. In order to improve the hydrophilicity of molecularly imprinted fluorescent materials, we have applied a combination of molecularly imprinted technology and amphiphilic block copolymers on MOFs for the first time. Amphiphilic PAVE copolymer is selected as the molecular imprinted functional monomer to improve the hydrophilicity of UiO-66-NH2. The synthesized PAVE-MOF-MIP has adequate water dispersion ability and fluorescence activity. When encountering oxytetracycline, PAVE-MOF-MIP will produce fluorescence quenching, it is used to construct a fluorescence detection platform for oxytetracycline detection. Compared with traditional MIP@MOF, PAVE-MOF-MIP has better water dispersion ability and detection accuracy. Under optimal conditions, the linear range of oxytetracycline detection is 10-100 μmol L-1, and the minimum limit of detection (LOD) is 86 nmol L-1. This paper proposes a novel approach to use amphiphilic block copolymers as molecularly imprinted monomers on MOFs, providing an innovative idea that has not been previously explored.

C-doped ZnO nanocomposites molecularly imprinted photoelectrochemical sensor for ultrasensitive and selective detection of oxytetracycline in milk.

Antibiotic monitoring remains vital to ensure human health and safety in the environment and foods. As the most popular detection method, photoelectrochemical (PEC) sensor can achieve rapid and accurate detection of antibiotics with the advantages of high sensitivity, easy-to-preparation process, as well as high selectivity. Herein, an extremely-efficient visible-light responsible ZnO/C nanocomposite was prepared and combined with acetylene black (as an enhanced conductive matrix), and the electron migration efficiency was greatly accelerated. Meanwhile, a molecularly imprinted polymer obtained by electrical agglomeration was conjugated as a specific recognizing site for target. Furthermore, the as-prepared rMIP-PEC sensor showed a low detection limit (8.75pmol L-1, S/N=3) in a wide linear detection range of 0.01-1000nmol L-1 for oxytetracycline (OTC), with excellent selectivity and long-term stability. Our work shed light on applying C-doped ZnO semiconductor and molecularly imprinted polymer as photoelectric active sensing materials for rapid and accurate analysis of antibiotics in foods and environment.

Detection of oxytetracycline in milk using a novel carbon dots-based fluorescence probe via facile pyrolysis synthesis.

Amphiphilic blue-fluorescence carbon dots (B-CDs) were synthesized via pyrolysis method with citric acid and oleamine as precursors. B-CDs are monodispersed in ethanol, toluene, and ultrapure water with the average particle sizes of 3.33nm, 2.05nm, and 4.12nm, respectively. The maximum emission wavelength of the B-CDs excitation at 370nm is located at 459nm. The B-CDs have good optical properties with excellent photostability. The fluorescence quantum yield (QY) of the as-prepared CDs is as high as 30.17%. The fluorescence of B-CDs is quenched because of static quenching by oxytetracycline. A high selective and sensitive fluorescence probe for detecting oxytetracycline was constructed with a linear range of 1.52-27.60µg/mL and the detection limit of 0.33µg/mL. The B-CDs-based fluorescence probe can be applied to analyze oxytetracycline in milk; the recoveries and relative standard are satisfactory. Furthermore, the B-CDs were exploited for imaging of SH-SY5Y cells. The results demonstrate that as-synthesized CDs can serve as a cellular imaging reagent owing to remarkable bioimaging performance. This work provides a new strategy for the detection of oxytetracycline in food.

A Turn-Off Fluorescent Biomimetic Sensor Based on a Molecularly Imprinted Polymer-Coated Amino-Functionalized Zirconium (IV) Metal-Organic Framework for the Ultrasensitive and Selective Detection of Trace Oxytetracycline in Milk.

Developing sensitive and effective methods to monitor oxytetracycline residues in food is of great significance for maintaining public health. Herein, a fluorescent sensor (NH2-UIO-66 (Zr)@MIP) based on a molecularly imprinted polymer-coated amino-functionalized zirconium (IV) metal-organic framework was successfully constructed and first used for the ultrasensitive determination of oxytetracycline. NH2-UIO-66 (Zr), with a maximum emission wavelength of 455 nm under 350 nm excitation, was prepared using a microwave-assisted heating method. The NH2-UIO-66 (Zr)@MIP sensor with specific recognition sites for oxytetracycline was then acquired by modifying a molecularly imprinted polymer on the surface of NH2-UIO-66 (Zr). The introduction of NH2-UIO-66 (Zr) as both a signal tag and supporter can strengthen the sensitivity of the fluorescence sensor. Thanks to the combination of the unique characteristics of the molecularly imprinted polymer and NH2-UIO-66 (Zr), the prepared sensor not only exhibited a sensitive fluorescence response, specific identification capabilities and a high selectivity for oxytetracycline, but also showed good fluorescence stability, satisfactory precision and reproducibility. The fabricated sensor displayed a fluorescent linear quenching in the OTC concentration range of 0.05-40 μg mL-1, with a detection limit of 0.012 μg mL-1. More importantly, the fluorescence sensor was finally applied for the detection of oxytetracycline in milk, and the results were comparable to those obtained using the HPLC approach. Hence, the NH2-UIO-66 (Zr)@MIP sensor possesses great application potential for the accurate evaluation of trace oxytetracycline in dairy products.

Voltammetric determination of oxytetracycline in milk and pharmaceuticals samples using polyurea modified glassy carbon electrode

Oxytetracycline (OTC) is one of the most commonly utilized broad spectrum antibiotic for the therapy of humans and animals. The present work describes the establishment of a simple, new and sensitive sensor based on elelctropolymerized polyurea modified glassy carbon electrode (EPPU/GCE) for OTC determination, which is one of the most frequently used antibiotics to treat certain diseases. Though urea is a simple, inexpensive and nontoxic, its use in the development of modified electrodes for electrochemical determination of pharmaceuticals has not been studied. The fabricated sensor (EPPU/GCE) was characterized via cyclic voltammetry and electrochemical impedance spectroscopy using Fe(CN)63-/4- solution as a probe. The electrochemical activity of poly(EPPU)/GCE for oxytetracycline oxidation was examined with phosphate buffer solution (PBS) of pH 7.5. A well-resolved and more enhanced two oxidative peaks for OTC solution in phosphate buffer solution (PBS) of pH 7.5 were observed at EPPU/GCE. The SWV measurement demonstrated a good linear range (1–200 µM) and detection limit (Ipa1 =1.01 ×10−1 µM and Ipa2 = 9.83 ×10−2 µM) for OTC. Electrochemical response of OTC at EPPU/GCE was not influenced by the presence of paracetamol, uric acid and glucose, showing good selectivity. The fabricated sensor has been effectively applied for detecting OTC in milk and four brands of veterinary injection samples, and the detected percentage recovery of OTC in each injection sample was above 99.25% of the labeled value and above 96% for milk sample. Thus, the developed sensor could potentially be used for electrochemical determination of OTC in other pharmaceuticals, biological, environmental and food samples.

Novel Electrochemical Aptasensor Based on Floral Zinc Oxide/Reduced Graphene Oxide/Colloidal Gold Composite for the Detection of Tetracycline, Doxycycline and Oxytetracycline in Milk

In this research, an electrochemical aptamer sensor based on the specific recognition of tetracycline, doxycycline and oxytetracycline was developed through flower-like zinc oxide/reduced graphene oxide/nano-gold composites. Firstly, floral zinc oxide had a large contact area, which bound more gold nanoparticles, and bound more adapters through Au–S bonds. Next, due to the poor conductivity of floral zinc oxide, the combination of floral zinc oxide and rGO was able to improve the conductivity. Finally, the rGO–ZnO–AuNPs composite was used as a platform to improve the electron transport rate on the glassy carbon electrode surface, enhance the electrochemical strength, and provide enough active sites for the capture of aptamers. After condition optimization, the lowest detection concentrations for tetracycline, doxycycline and oxytetracycline were 0.33, 0.28 and 0.3 ng·ml−1 respectively. In addition, this aptasensor had good stability, selectivity, anti-interference and reproducibility. It would be further applied to the detection of antibiotics in milk.

Mesoporous silica-based molecularly imprinted fluorescence sensor for the ultrafast and sensitive recognition of oxytetracycline

Molecularly imprinted sensor has been a common chemical sensor for the selective detection of target. Yet, the rapid detection of target was one of the remaining problems, which needs to be diligently improved. Herein, a molecularly imprinted mesoporous silicon material (N-CDs@mMIPs) was successfully prepared for the rapid, sensitive and selective detection of oxytetracycline (OTC). Non-toxic nitrogen-doped carbon quantum dots (N-CDs) with high fluorescence performance was chosen as a detectable fluorescence signal, OTC was the target analysis, 3-Aminopropyltriethoxysilane (APTES) as the functional monomer, tetraethyl silicate (TEOS) as the crossing link agent and cetyl trimethyl ammonium bromide (CTAB) as the pore-foaming agent. N-CDs@mMIPs was synthesized by the removal of CTAB and OTC. Under the optimal test conditions, the resultant N-CDs@mMIPs showed a faster response time within 0.5 min (30 s) and a lower detection limit of 0.035 μmol·L−1 compared with molecularly imprinted sensor without mesoporous structure (N-CDs@MIPs) and other molecularly imprinted sensors. Consequently, N-CDs@mMIPs was applied for the detection of OTC in milk and honey, satisfied recovery rates of 99.80 %–100.60 % and 99.75 %–102.10 % were obtained respectively. In general, the pore structure in mesoporous silicon accelerated the mass transfer rate between target and fluorescent substance, which greatly shortened the detection time of N-CDs@mMIPs to OTC. Furthermore, the pore structure in mesoporous silicon could effectively avoid the self-aggregation of N-CDs, thus improved the sensitivity of N-CDs@mMIPs.

Detection of Antibiotic Residues of Penicillin and Oxytetracycline in Milk

Detection of Antibiotic Residues of Penicillin and Oxytetracycline in Milk

A Novel Fluorescent Aptasensor for Sensitive Detection of Oxytetracycline Based on Gold Nanoparticles and OTC-Eu

We developed a simple and selective fluorescent aptasensor for the detection of oxytetracycline (OTC) using aptamer-conjugated gold nanoparticles (AuNPs) and a complex formed between oxytetracycline and a europium cation. In this study, AuNPs were modified with an OTC aptamer using two methods (Tween and NaCl methods). In the absence of OTC, an OTC-Eu3+ complex binds to the aptamer in the aptamer-conjugated AuNPs to give weak fluorescence emission. However, in the presence of OTC, the aptamer interacts with its target, causing a strong fluorescence emission. Under optimum conditions, the designed method showed high selectivity for OTC and a good linear range to OTC concentration from 15 to 500 nM with a limit of detection (LOD) of 10.6 nM for the NaCl method and linear range over 15–500 nM with an LOD of 8.8 nM for the Tween method. This biosensor was successfully employed to quantify OTC in milk and tablet samples.

A fluorescent sensing strategy for ultrasensitive detection of oxytetracycline in milk based on aptamer-magnetic bead conjugate, complementary strand of aptamer and PicoGreen.

Misuse of antibiotics in animal husbandry and presence of their residues in animal foods is a serious crisis worldwide and thus, monitoring the level of them in food samples is vital for human health. Herein, a fluorescent aptasensor was developed for highly sensitive quantification of oxytetracycline (OTC) in food samples. This method is based on OTC aptamer conjugated to magnetic beads, functioned as recognition element, complementary strand of OTC aptamer, and PicoGreen (PG) as a sensitive double-stranded DNA (dsDNA) fluorescent dye. Formation of OTC aptamer-magnetic bead conjugate provides the opportunity of sample condensation and separation technology. Additionally, the presence of complementary strand leads to significant fluorescence signal alteration of aptasensor in the presence or absence of target and a noteworthy improvement of the aptasensor sensitivity. In the absence of target, complementary strand could bind to aptamer and form dsDNA on the surface of magnetic bead. As a consequence, adding PG to the sample leads to observation of high fluorescence signal from sample. In contrast, once OTC is added to the sample, it binds to OTC aptamer-magnetic bead complex and prevents hybridization of OTC aptamer and its complementary strand. Hence, after addition of PG to the sample, a weak fluorescence intensity is measured. Under optimized conditions, the linear ranges for OTC detection were 0.2-2nM and 2-800nM. The detection limit was calculated to be as low as 0.15nM for the fabricated aptasensor. Besides the great sensitivity, proposed method demonstrated superior specificity towards OTC once it was used against several antibiotics. More significantly, the recovery rates of OTC in milk ranged from 96.46% to 101.5%, implying the great feasibility of designed sensor as well as its potential to be employed for analysis of OTC in real samples.

Efficient fabrication of ratiometric fluorescence imprinting sensors based on organic-inorganic composite materials and highly sensitive detection of oxytetracycline in milk

Ratiometric fluorescence imprinting sensors (GQDs/CdTe@MIPs) were successfully constructed by precipitation polymerization method for the recognition and detection of oxytetracycline (OTC) in milk samples. GQDs/CdTe@MIPs were characterized by scanning electron microscope (SEM), transmission electron microscope (TEM), fourier transform infrared (FT-IR), thermal gravity analysis (TGA), UV–visible spectroscopy (UV–vis) and X-ray photoelectron spectroscopy (XPS) techniques. A satisfying linear relationship under 0–80 μM OTC concentration (R2 = 0.99699) was exhibited. High sensitivity was showed with the limit of detection of 3.5 nM and high recovery ranged from 99.93% to 100.20%. In addition, the selectivity of GQDs/CdTe@MIPs to OTC was well comparing with other antibiotics. With the injection of different concentrations of OTC, the fluorescent color change of GQDs/CdTe@MIPs under the 365 nm UV lamp further verified that GQDs/CdTe@MIPs were used successfully for the visual detection to OTC in milk samples.

Electrochemical Sensing Fabricated with Ta2O5 Nanoparticle-Electrochemically Reduced Graphene Oxide Nanocomposite for the Detection of Oxytetracycline.

A novel tantalum pentoxide nanoparticle-electrochemically reduced graphene oxide nanocomposite-modified glassy carbon electrode (Ta2O5-ErGO/GCE) was developed for the detection of oxytetracycline in milk. The composition, structure and morphology of GO, Ta2O5, and Ta2O5-ErGO were characterized by X-ray diffraction (XRD) and scanning electron microscopy (SEM). Oxytetracycline electrochemical behavior on the bare GCE, GO/GCE, ErGO/GCE, and Ta2O5-ErGO/GCE was studied by cyclic voltammetry. The voltammetric conditions (including scan rate, pH, deposition potential, and deposition time) were systematically optimized. With the spacious electrochemical active area, the Ta2O5-ErGO/GCE showed a great magnification of the oxidation signal of oxytetracycline, while that of the other electrodes (GCE, GO/GCE, ErGO/GCE) could not reach the same level. Under the optimum conditions, the currents were proportional to the oxytetracycline concentration in the range from 0.2 to 10 μM, and a low detection limit of 0.095 μM (S/N = 3) was detectable. Moreover, the proposed Ta2O5-ErGO/GCE performed practically with satisfactory results. The preparation of Ta2O5-ErGO/GCE in the current work provides a minor outlook of detecting trace oxytetracycline in milk.

Impact of the presence of oxytetracycline residues in milk destined for the elaboration of dairy products: The specific case of mature goat cheese

This study evaluated instrumental parameters (chemical composition, colour, texture and microstructure) and sensory characteristics of goat cheese (60-day maturation) made with milk spiked with oxytetracycline at different levels: 0, 50, 100 (maximum residue limit; MRL) and 200 μg kg−1. Additionally, the influence of this antibiotic on the cheese making process was evaluated and proved that the presence of oxytetracycline in milk significantly delayed the total time of manufacture in proportion to its concentration. The presence of this antibiotic in raw milk, even at a concentration of up to double the MRL, affected some of the parameters only slightly (pH, FFA concentration, luminosity, springiness and chewiness) in the ripened cheeses, without being perceptible by the sensory panel. Consequently, cheese made from milk containing oxytetracycline would go unnoticed by consumers.

A colorimetric aptasensor for selective detection of oxytetracycline in milk, using gold nanoparticles and oxytetracline-short aptamer

Objective (s): In light of misuse of antibiotics in animal husbandry and their side effects on human health, there is an argent need to develop simple and rapid methods for determining the quantification of antibiotics in biological systems. Materials and Methods: In this work a facile and ultrasensitive colorimetric aptasensor was reported for detection of oxytetracycline (OTC) in water and milk samples employing OTC-short aptamer and gold nanoparticles (AuNPs). Results: In the presence of OTC, the interaction between OTC and its aptamer leads to the separation of OTC aptamer from the surface of AuNPs which is followed by the aggregation of AuNPs by salt, showing an evident color change from red to blue. On the contrary, in the absence of OTC, the attachment of aptamer on the surface of AuNPs can protect AuNPs against salt-induced aggregation with a wine-red color. The proposed aptasensor exhibits excellent sensitivity for detection of OTC with linear range between 20 to 2000 nM with limit of detection (LOD) as low as 10 nM. Furthermore, this strategy was applied to detect OTC in spiked milk samples and presented satisfying linear range from 25 to 1500 nM with the LOD of 20 nM. Conclusion: Owing to demonstrating appropriate sensitivity and selectivity, the designed biosensor can be considered as a promising tool to be applied in the field of biomedicine and food safety.

Transfer of oxytetracycline from ovine spiked milk to whey and cheese

Cheese-making trials with ovine milk spiked with oxytetracycline (OTC) at maximum residue limit (MRL) level were performed to study the OTC distribution between whey and cheese, and assess its effect in cheese-making process and cheese composition. An in-house validated method, based on liquid chromatography-tandem mass spectrometry, was adopted to detect OTC in milk, whey and cheeses. The MRL OTC spike induced a delay in the pH lowering causing a higher moisture content in 1-day OTC cheese compared with the control cheese. No effects of OTC were observed on the mass balance of the process, on the recovery of fat and protein and, in general, on physico-chemical parameters and gross composition of obtained cheeses. OTC was mainly recovered in the 1-day cheeses (61 ± 5%). Despite a 17 ± 8% OTC reduction observed during cheese ripening, probably due to partial degradation, remaining residues were not negligible and could contribute to reach the acceptable daily intake.

Applicability of Screening Tests for Oxytetracycline in the Milk of Three Breeds of Goats

Antibiotics are widely used in animal husbandry, and the presence of antibiotic residues in milk is a health hazard. The objectives of this study were to determine residual amounts of oxytetracycline in the milk of three breeds of goats using high-pressure liquid chromatography (HPLC) analysis and screening tests. It was also essential to explore the safe withdrawal period of oxytetracycline in lactating goats and examine the applicability of Charm ROSA and SNAP screening tests. The qualitative results of these tests were compared with the quantitative results of the HPLC method. Fifteen milking does, five each from the Alpine, LaMancha, and Nubian breeds, were selected from the herd at Prairie View A&M University. Milk samples containing antibiotic residues were deproteinized by HCl and acetonitrile, and then oxytetracycline was extracted from the supernatant. The residues of oxytetracycline in goat's milk up to 110 h after injection were qualitatively detected using the Charm ROSA test. Similarly, the SNAP test detected the antibiotic residues in milk up to 110 h after treatment. The HPLC results indicated that oxytetracycline residues in milk from Alpine goats were below the tolerance level (300 ng/ml) 82 h after drug treatment (72 h for LaManchas, 58 h for Nubians); however, the results of the screening tests would indicate longer withdrawal periods for milk from the breeds of goats studied, which would result in economic losses to goat's milk producers. The results of this study also indicated that oxytetracycline was not stable in raw goat's milk at refrigeration temperature or during pasteurization and that the concentrations decreased significantly. Commercial goat's milk is usually exposed to several hours of refrigeration and then to pasteurization. The results of this study indicated that, if oxytetracycline was present in raw goat's milk, the concentration would decrease significantly before it was marketed.

First report on a BODIPY-based fluorescent probe for sensitive detection of oxytetracycline: application for the rapid determination of oxytetracycline in milk, honey and pork

An effective solution for oxytetracycline detection in actual food samples by a novel BODIPY-based fluorescent probe.