Eu3+-functionalized covalent organic framework for ratiometric fluorescence detection and adsorption of tetracycline and information steganography.

Functional materials with organic/inorganic composites as the main matrix and rare earth ion complexes as the guest have shown a very broad application prospect for antibiotic sensors. However, Eu3+-complex often relies on a single fluorescence response signal, which is susceptible to changes in the detection environment and cannot simultaneously detect and remove tetracycline (TC). Herein, green fluorescent covalent two-dimensional organic framework (COF-TD) is synthesized, followed by modification of Eu3+ to synthesize COF-TD@Eu3+. In the ratiometric sensor, Eu3+ serves as the recognition site and specific response probe for TC, while COF-TD is the fluorescence reference and carrier for Eu3+. Due to the antenna effect, TC enhances the red fluorescence of Eu3+, while the green fluorescence of COF-TD remains almost stable. Based on the change of fluorescence intensity and fluorescence color from green to red, the efficient ratiometric sensing can be finished in 1 min. The developed method shows high sensitivity with a detection limit of 0.3 µM and high selectivity to TC which makes the method applicable to detect TC in traditional Chinese medicine preparations. In addition, due to the high specific surface area of COFs and specific adsorption sites, COF-TD@Eu3+ also shows good performance for TC removal. The findings show that the maximum adsorption capacity is 137.3 mg g-1 and the adsorption equilibrium is reached in 30 min. Smartphone assisted COF-TD@Eu3+ for both ratiometric fluorescence detection and detecting the absorption of TC is proposed for the first time. The molecular cryptosteganography that transforms the selective response of COF-TD@Eu3+ to binary strings is anticipated to advance utilization of nanomaterials in logic sensing and information safety.

Heterometallic Eu/Zn-MOF-based ratiometric sensing platform: Highly sensitive fluorescence / second-order scattering identification of tetracycline analogs and its molecular informatization applications.

The traditional preparation method of ratiometric probes faces challenges such as cumbersome preparation and low sensitivity. Thus, there is an urgent need to provide a simple method of preparing a highly sensitive ratiometric probe. Here, Eu3+-doped zinc-based organic framework (Eu/Zn-MOF) was prepared through hydrothermal method for the detection of tetracycline analogs (TCs). Under the same excitation conditions, the probe can simultaneously display valuable fluorescence and second-order scattering signals. The developed probe enabled specific identification and fast detection (1 min) of TCs, including tetracycline, oxytetracycline, doxycycline, and chlortetracycline. The linear detection ranges of tetracycline, oxytetracycline, doxycycline and chlortetracycline were respectively 100 nM - 200 µM, 100 nM - 200 µM, 98 nM - 195 µM, and 97 nM - 291 µM, and the corresponding detection limits were respectively 15.79 nM, 20.83 nM, 15.31 nM, and 28.30 nM. The developed sensor was successfully applied to detect TCs in real samples, and the recovery rate was from 92.54 % to 109.69 % and the relative standard deviation was from 0.04 % to 2.97 %. Moreover, the heterometallic Eu/Zn-MOF was designed as a ratiometric neuron for Boolean logic computing and information encryption based on the specific identification of TCs. As a proof of concept, molecular steganography was successfully employed to encode, store, and conceal information by transforming the specific identification patterns of Eu/Zn-MOF into binary strings. This study is anticipated to advance the application of metal-organic frameworks in logic detection and information security, and bridging the gap between molecular sensors and the realm of information.

Recent progress in lanthanide-based fluorescent nanomaterials for tetracycline detection and removal.

Tetracycline (TC) has been widely used in clinical medicine and animal growth promotion due to its broad-spectrum antibacterial properties and affordable prices. Unfortunately, the high toxicity and difficult degradation rate of TC molecules make them easy to accumulate in the environment, which breaks the ecological balance and seriously threatens human health. Rapid and accurate detection of TC residue levels is important for ensuring water quality and food safety. Recently, fluorescence detection technology of TC residues has developed rapidly. Lanthanide nanomaterials, based on the high luminescence properties of lanthanide ions and the high matching with TC energy levels, are favored in the real-time trace detection of TC due to their advantages of high sensitivity, rapidity, and high selectivity. Therefore, they are considered potential substitutes for traditional detection methods. This review summarizes the synthesis strategy, TC response mechanism, removal mechanism, and applications in intelligent sensing. Finally, the development of lanthanide nanomaterials for TC fluorescence detection and removal is reasonably summarized and prospected. This review provides a reference for the establishment of a method for the accurate determination of TC content in complex food matrices.

[Antibiotic Contamination Characteristics and Ecological Risk Assessment in Soils of Large-scaled Culturing Farms].

The soils of different land use types in large-scaled culturing farms were collected for detecting the contents of antibiotics in these soils by applying high-performance liquid chromatography, analyzing the relationship between antibiotics and physicochemical properties of soils, as well as performing the ecological risk assessment of antibiotics in the soils of culturing farms by using the risk quotient method. The results showed that the surrounding soils of the culturing farm were contaminated by antibiotics to varying degrees, in which tetracycline had the highest detection rate and average content. Among the soils of different land use types, the average contents of antibiotics were ranked as corn field （1.48 µg·kg-1）>0.5 meters outside the farm fence （1.27 µg·kg-1）>yam field （1.03 µg·kg-1）>pasture （0.69 µg·kg-1）>woodland （0.18 µg·kg-1）. According to the redundancy analysis results, the total nitrogen, total phosphorus, and cellulase had a great impact on the antibiotic content in soil samples. It can be concluded from the ecological risk assessment that oxytetracycline （OTC）, chlortetracycline （CTC）, doxycycline （DOC）, ciprofloxacin （CIP）, and tetracycline （TC） were categorized in the low risk level. Sulfadiazine （SM） and sulfadimidine （SM2） were categorized in the medium and high risk levels. It is of the upmost importance to control the antibiotic contamination in surrounding soils of culturing farms and to strengthen the management of veterinary antibiotics.

Sensitive and High-Throughput Time-Resolved Luminescence Detection of Tetracycline in Milk for Eliminating Background Fluorescence on a Miniaturized Apparatus.

Fluorescence detection has always suffered from high background fluorescence from real samples such as milk. Therefore, cumbersome pretreatments of samples were necessary to remove the fluorescent substances but led to long processing times and low efficiency. Time-resolved luminescence detection is a powerful technique for eliminating short-lived background fluorescence without additional pretreatments. However, the related instruments are usually equipped with high-speed excitation sources and detectors, which are always bulky and expensive. Herein, we developed a low-cost and miniaturized imaging system for high-throughput time-gated luminescence detection. An UV LED array was used to excite multiple samples, the luminescence of which could be detected by a smartphone simultaneously. An analog circuit was designed to synchronize the LED to the mechanical chopper to eliminate the background signals resulting from scattering and short-lived autofluorescence. Compared to other synchronous circuits based on FPGAs and microcontrollers, this analog circuit required no programming and memory. For the first time, high-throughput time-resolved luminescence detection of tetracycline in milk without any separation or enrichment was achieved by utilizing a smartphone as a camera, and the scattered signals and the background fluorescence were eliminated efficiently. The limit of detection reached as low as 53 nM (∼0.024 ppm), lower than the residue limit set by the European Union. This high-throughput time-gated luminescence detection method can be used for quantitative analysis of many real samples with high background fluorescence.

Highly efficient and sensitive detection of tetracycline in environmental water: Insights into the synergistic mechanism of biomass-derived carbon dots and N-methyl pyrrolidone solvent.

The tetracycline (TC) residue in water environment has caused serious public safety issue. Thus, efficient sensing of TC is highly desirable for environmental protection. Herein, biomass-derived nitrogen-doped carbon dots (N-CDs) synthesized from natural Ophiopogon japonicus f. nanus (O. japonicus) were used for TC detection. The unique solvent synergism efficiently enhanced detection sensitivity, and the detailed sensing mechanism was deeply investigated. The blue fluorescence of N-CDs was quenched by TC via static quenching and inner filter effect. Moreover, the enhancement of green fluorescence from deprotonated TC was firstly proposed and sufficiently verified. The solvent effect of N-methyl pyrrolidone (NMP) and the fluorescence resonance energy transfer (FRET) with N-CDs achieved an instantaneous enhancement of the green emission by 64-fold. Accordingly, a ratiometric fluorescence method was constructed for rapid and sensitive sensing of TC with a low detection limit of 6.3 nM within 60 s. The synergistic effect of N-CDs and solvent assistance significantly improved the sensitivity by 7-fold compared to that in water. Remarkably, the biomass-derived N-CDs displayed low cost, good solubility, and desired stability. The deep insights into the synergism with solvent can provide prospects for the utilization of biomass-based materials and broaden the development of advanced sensors with promising applications.

Magnetic Immunoassay Based on Au Pt Bimetallic Nanoparticles/Carbon Nanotube Hybrids for Sensitive Detection of Tetracycline Antibiotics.

Misusage of tetracycline (TC) antibiotics residue in animal food has posed a significant threat to human health. Therefore, there is an urgent need to develop highly sensitive and robust assays for detecting TC. In the current study, gold and platinum nanoparticles were deposited on carbon nanotubes (CNTs) through the superposition method (Au@Pt/CNTs-s) and one-pot method (Au@Pt/CNTs-o). Au@Pt/CNTs-s displayed higher enzyme-like activity than Au@Pt/CNTs-o, which were utilized for the development of sensitive magnetic immunoassays. Under the optimized conditions, the limits of detection (LODs) of magnetic immunoassays assisted by Au@Pt/CNTs-s and Au@Pt/CNTs-o against TCs could reach 0.74 ng/mL and 1.74 ng/m, respectively, which were improved 6-fold and 2.5-fold in comparison with conventional magnetic immunoassay. In addition, the measurement of TC-family antibiotics was implemented by this assay, and ascribed to the antibody used that could recognize TC, oxytetracycline, chlortetracycline, and doxycycline with high cross-reactivity. Furthermore, the method showed good accuracy (recoveries, 92.1-114.5% for milk; 88.6-92.4% for pork samples), which also were applied for determination of the targets in real samples. This study provides novel insights into the rapid detection of targets based on high-performance nanocatalysts.

Microwave-assisted preparation of yellow fluorescent graphitic carbon nitride quantum dots for trace tetracycline-specific detection.

Tetracycline (TC) is extensively utilized in livestock breeding, aquaculture, and medical industry. TC residues seriously harm food security, the environment, and human health. There is an urgent need to exploit a highly efficient and sensitive testing method to monitor TC residue levels in aquatic environments. In this study, graphitic carbon nitride quantum dots (g-CNQDs) were successfully synthesized by a one-step microwave-assisted method using citric acid and urea as precursors. The as-prepared g-CNQDs with size of 1.25-3.75 nm exhibited bright yellow fluorescence at 523 nm when excited at 397 nm. Interestingly, this characteristic fluorescence emission of g-CNQDs could be selectively and efficiently quenched by TC. Based on this phenomenon, for TC detection was successfully explored and applied in real water samples. Wide linear scope of 7-100 µM, low detection limit (LOD) of 0.48 µM, satisfactory recovery of 97.77%-103.4%, and good relative standard deviation (RSD) of 1.05-5.87% were obtained. Mechanism investigations revealed that the static quenching and the inner filter effect (IFE) were responsible for this fluorescence quenching between g-CNQDs and TC. This work not only provided a facile approach for g-CNQDs synthesis but also constructed a g-CNQDs-based fluorescent sensor platform for the highly sensitive and selective detection of TC in aquatic environments.

Novel Schiff's base-assisted synthesis of metal-ligand nanostructures for multi-functional applications: Detection of catecholamines/antibiotics, removal of tetracycline, and antifungal treatment against plant pathogens.

The development of nanozymes (NZ) for the simultaneous detection of multiple target chemicals is gaining paramount attention in the field of food and health sciences, and waste management industries. Nanozymes (NZ) effectively compensate for the environmental vulnerability of natural enzymes. Considering the development gap of NZ with diverse applications, we synthesized versatile Schiff's base ligands following a facile route and readily available starting reagents (glutaraldehyde, aminopyridines). DPDI, one of the synthesized ligands, readily reacted with transition metal ions (Cu+2, Ag+1, Zn+2 in specific) under ambient conditions, yielding the corresponding nanoparticles/MOF. The structures of ligands and their products were confirmed using various analytical techniques. The enzymatic efficacy of DPDI-Cu (km 0.25 mM=, Vmax = 10.75 µM/sec) surpassed Tremetese versicolor laccase efficacy (km 0. 5 mM=, Vmax = 2.15 µM/sec). Additionally, DPDI-Cu proved resilient to changing pH, temperature, ionic strength, organic solvent, and storage time compared to laccase and provided reusability. DPDI-Cu proved promising for colorimetric detection of dopamine, epinephrine, catechol, tetracycline, and quercetin. The mechanism of oxidative detection of TC was studied through LC/MS analysis. DPDI-Cu-bentonite composite efficiently adsorbed tetracycline with maximum Langmuir adsorption of 208 mg/g. Moreover, DPDI/Cu and DPDI-Ag nanoparticles possessed antifungal activity exhibiting a minimum inhibitory concentration of 400 µg/mL and 3.12 µg/mL against Aspergillus flavus. Florescent dye tracking and SEM/TEM analysis confirmed that DPDI-Ag caused disruption of the plasma membrane and triggered ROS generation and apoptosis-like death in fungal cells. The DPDI-Ag coating treatment of wheat seeds confirmed the non-phytotoxicity of Ag-NPs.

A thorough investigation into the adsorption behavior of sophorolipid-modified fly ash towards compound pollution of lead and tetracycline.

Heavy metal ions and antibiotics were simultaneously detected in authentic water systems. This research, for the first time, employed synthesized sophorolipid-modified fly ash(SFA) to eliminate tetracycline(TC) and lead(Pb2+) from wastewater. Various characterization techniques, including SEM-EDS, FTIR, XPS, BET, and Zeta, were employed to investigate the properties of the SFA. The results showed that the sophorolipid modification significantly improved the fly ash's adsorption capacities for the target pollutants. The static adsorption experiments elucidated the adsorption behaviors of SFA towards TC and Pb2+ in single and binary systems, highlighting the effects of different Environmental factors on the adsorption behavior in both types of systems. In single systems, SFA exhibited a maximum adsorption capacity of 128.96 mg/g for Pb2+ and 55.57 mg/g for TC. The adsorption of Pb2+ and TC followed pseudo-second-order kinetics and Freundlich isotherm models. The adsorption reactions are endothermic and occur spontaneously. SFA demonstrates varying adsorption mechanisms for two different types of pollutants. In the case of Pb2+, the primary mechanisms include ion exchange, electrostatic interaction, cation-π interaction, and complexation, while TC primarily engages in hydrogen bonding, π-π interaction, and complexation. The interaction between Pb2+ and TC has been shown to improve adsorption efficiency at low concentrations. Additionally, adsorption-desorption experiments confirm the reliable cycling performance of modified fly ash, highlighting its potential as a cost-effective and efficient adsorbent for antibiotics and heavy metals.

An investigation into the aging mechanism of disposable face masks and the interaction between different influencing factors.

In the natural environment, a symphony of environmental factors including sunlight exposure, current fluctuations, sodium chloride concentrations, and sediment dynamics intertwine, potentially magnifying the impacts on the aging process of disposable face masks (DFMs), thus escalating environmental risks. Employing Regular Two-Level Factorial Design, the study scrutinized interactive impacts of ultraviolet radiation, sand abrasion, acetic acid exposure, sodium chloride levels, and mechanical agitation on mask aging. Aging mechanisms and environmental risks linked with DFMs were elucidated through two-dimensional correlation analyses and risk index method. Following a simulated aging duration of three months, a single mask exhibited the propensity to release a substantial quantity of microplastics, ranging from 38,800 ± 360 to 938,400 ± 529 particles, and heavy metals, with concentrations from 0.06 ± 0.02 µg/g (Pb) to 29.01 ± 1.83 µg/g (Zn). Besides, specific contaminants such as zinc ions (24.24 µg/g), chromium (VI) (4.20 µg/g), thallium (I) (0.92 µg/g), tetracycline (0.51 µg/g), and acenaphthene (1.73 µg/g) can be adsorbed significantly by aged masks. The study elucidates pivotal role of interactions between ultraviolet radiation and acetic acid exposure in exacerbating the environmental risks associated with masks, while emphasizing the pronounced influence of many other interactions. The research provides a comprehensive understanding of the intricate aging processes and ensuing environmental risks posed by DFMs, offering valuable insights essential for developing sustainable management strategies in aquatic ecosystems.

Construction of colorimetric sensor arrays using steel slag-based composites for highly sensitive detection of tetracycline antibiotics.

Sensor array methods have received much attention in recent years. In this study, a colorimetric sensor array consisting of three kinds of steel slag-based composites (including porphyrin-functionalized non-magnetic steel slag (NMSS-Por), alkali-excited steel slag (A-SS), and platinum modified steel slag (ALANH-Pt)) was developed for the detection and recognition of tetracycline antibiotics (TCs) such as tetracycline (TC), oxytetracycline (OTC) and doxycycline (DOX). Linear discriminant analysis (LDA) and hierarchical cluster analysis (HCA) showed that the colorimetric sensor array has excellent recognition ability for TCs. The detection limits of this sensor array for TC, OTC, and DOX were 0.059 µM, 0.111 µM and 0.118 µM, respectively, which provided higher sensitivity compared to the colorimetric sensors composed of a single steel slag-based composite material. At the same time, the array sensor has anti-interference ability, and this study provides a new application route for steel slag.

Sensitive and rapid determination of tetracycline antibiotic by carrot juice-derived carbon dots as a fluorescent probe.

The antibiotic tetracycline can be efficiently used as medicine for the deterrence of bacterial infections in humans, animals, and plants. However, the unprecedented use of tetracycline is of great concern owing to its low biodegradability, extensive usage, and adverse impacts on the environment and water quality. In this study, a sensitive spectrofluorometric method was proposed for the direct determination of tetracycline, based on biocompatible fluorescent carbon dots (CDs). The synthesis of CDs was performed by adopting a green hydrothermal procedure from carrot juice without requiring surface passivation or outflowing any environmentally hazardous waste. X-ray diffraction analysis and transmission electron microscopy revealed amorphous spherical-shaped CDs that exhibited blue emission under blue illumination. The fabricated fluorescent probe directly detected tetracycline in the concentration range of 4.00 × 10-6 to 1.55 × 10-5 mol L-1 with an LOD of 1.33 × 10-6 mol L-1. The performance of the probe was assessed in a tap water sample, with recovery values between 80.70 and 103.60%. The method's greenness was evaluated using the Analytical Green metric approach (AGREE) and confirmed to be within the green range. The developed method is facile, rapid, cost-effective, and offers a wide linear range and satisfactory selectivity, making it potentially suitable for determining tetracycline in water applications.

Performance test and analysis of tetracycline degradation using a Micro-Nano Bubble system.

Antibiotics and organic residues from Tetracycline (TC) and other pharmaceuticals administered to aquatic living organism have negative impacts on aquatic environment by killing-off non-target living organisms and developing antibiotic-resistant bacteria. In this study, Micro-Nano Bubble (MNB) system was used to remove TC residues. MNB system demonstrated good level of degradation efficiency, as resulted in experiment where in time of 100 min, the TC degraded at rate of 82.66% from its initial concentration of TC when the initial concentration was 1 mg/L. When the initial concentration was increased to 10 mg/L, MNB system degraded TC at 64.35% of their initial, this means MNB system demonstrated good level of efficiency for TC removal and indicated that it is more efficient in TC degradation under the conditions of low initial TC concentration and high availability of dissolved oxygen (DO). In the system as the temperature increased there was a significant decrease in DO saturation which was related to the TC complex structure that contain multiple function groups such as amino groups, hydroxyl and carboxyl which possess high strong affinity with oxygen that leads to their adsorption onto bubble surface. This study provides significant insights into the application of MNB system for the removal of organic residues within aquatic ecosystem and underscores the need for further exploration of MNB technology for environmental remediation.

Integrated Eu3+ loaded covalent organic framework with smartphone for ratiometric fluorescence detection of tetracycline.

Developing rapid tetracycline sensing system is of great significance to monitor the illegal addition to drugs and pollution to food and ecosystem. By loading covalent organic frameworks (COFs) with Eu3+, a new hybridized material (COF@Eu3+) was prepared for tetracycline determination. Based on the Schiff base reaction, the COFs were by synthesized through solvent evaporation in 30 min at room temperature. Thereafter, Eu3+ was modified into COFs to develop the COF@Eu3+ sensing platform by adsorption and coordination. In presence of tetracycline, tetracycline can displace water molecules and coordinate with Eu3+ through the antenna effect. As a result, the red fluorescence of Eu3+ was enhanced by tetracycline with green fluorescence of COF as a reference. The developed ratiometric fluorescence sensor exhibits a linear range of 0.1-20 µM for detecting tetracycline with a detection limit of 30 nM. Integrated with a smartphone, the rapid tetracycline detection can be realized in situ, which is potential for high-throughput screening of tetracycline contaminated samples. Furthermore, the COF@Eu3+ fluorescence sensor has been successfully applied to the detection of tetracycline in traditional Chinese medicine compound preparation with satisfied recoveries. Therefore, a smartphone-assisted device was successfully developed based on Eu3+-functionalized COF, which is an attractive candidate for further applications of fluorescence sensing and visual detection.

A dual-response ratiometric fluorescent sensor by europium-doped silicon nanoparticles for fluorescent and smartphone imaging detection of tetracycline.

Given the threat to human health posed by the abuse of tetracycline (TC), the development of a portable, on-site methods for highly sensitive and rapid TC detection is crucial. In this work, we initially synthesized europium-doped silicon nanoparticles (SiEuNPs) through a facile one-pot microwave-assisted method. Due to its blue-red dual fluorescence emission (465 nm/621 nm), which was respectively attributed to the silicon nanoparticles and Eu3+, SiEuNPs were designed as a ratiometric fluorescent sensor for TC detection. For the dual-signal reverse response mechanism: TC quenched the blue emission from silicon nanoparticles through inner filter effect (IFE), and enhanced the red emission through "antenna effect" (AE) between TC and Eu3+, the nanoprobe was able to detect TC within a range of 0.2-10 µM with a limit of detection (LOD) of 10.7 nM. Notably, the equilibrium detection time was only 1 min, achieving rapid TC detection. Furthermore, TC was also measured in real samples (tap water, milk and honey) with recoveries ranging from 95.7 % to 117.0 %. More importantly, a portable smartphone-assisted on-site detection platform was developed, enabling real-time qualitative identification and semi-quantitative analysis of TC based on fluorescence color changes. This work not only provided a novel doped silicon nanoparticles strategy, but also constructed a ratiometric sensing platform with dual-signal reverse response for intuitive and real-time TC detection.

Detection of Tetracycline with a CRISPR/Cas12a Aptasensor Using a Highly Efficient Fluorescent Polystyrene Microsphere Reporter System.

CRISPR-based diagnostics use the CRISPR-Cas system trans-cleavage activity to identify specific target sequences. When activated, this activity cleaves surrounding reporter molecules, producing a detectable signal. This technique has great specificity, sensitivity, and rapid detection, making it an important molecular diagnostic tool for medical and infectious disease applications. Despite its potential, the present CRISPR/Cas system has challenges with its single-stranded DNA reporters, characterized by low stability and limited sensitivity, restricting effective application in complex biological settings. In this work, we investigate the trans-cleavage activity of CRISPR/Cas12a on substrates utilizing fluorescent polystyrene microspheres to detect tetracycline. This innovative discovery led to the development of microsphere probes addressing the stability and sensitivity issues associated with CRISPR/Cas biosensing. By attaching the ssDNA reporter to polystyrene microspheres, we discovered that the Cas12a system exhibits robust and sensitive trans-cleavage activity. Further work revealed that the trans-cleavage activity of Cas12a on the microsphere surface is significantly dependent on the concentration of the ssDNA reporters. Building on these intriguing discoveries, we developed microsphere-based fluorescent probes for CRISPR/Cas aptasensors, which showed stability and sensitivity in tetracycline biosensing. We demonstrated a highly sensitive detection of tetracycline with a detection limit of 0.1 µM. Finally, the practical use of a microsphere-based CRISPR/Cas aptasensor in spiked food samples was proven successful. These findings highlighted the remarkable potential of microsphere-based CRISPR/Cas aptasensors for biological research and medical diagnosis.

Acoustofluidic one-step production of plasmonic Ag nanoparticles for portable paper-based ultrasensitive SERS detection of bactericides.

SERS measurements for monitoring bactericides in dairy products are highly desired for food safety problems. However, the complicated preparation process of SERS substrates greatly impedes the promotion of SERS. Here, we propose acoustofluidic one-step synthesis of Ag nanoparticles on paper substrates for SERS detection. Our method is economical, fast, simple, and eco-friendly. We adopted laser cutting to cut out appropriate paper shapes, and aldehydes were simultaneously produced at the cutting edge in the pyrolysis of cellulose by laser which were leveraged as the reducing reagent. In the synthesis, only 5 µL of Ag precursor was added to complete the reaction, and no reducing agent was used. Our recently developed acoustofluidic device was employed to intensely mix Ag+ ions and aldehydes and spread the reduced Ag nanoparticles over the substrate. The SERS substrate was fabricated in 1 step and 3 min. The standard R6G solution measurement demonstrated the excellent signal and prominent uniformity of the fabricated SERS substrates. SERS detection of the safe concentration of three bactericides, including tetracycline hydrochloride, thiabendazole, and malachite green, from food samples can be achieved using fabricated substrates. We take the least cost, time, reagents, and steps to fabricate the SERS substrate with satisfying performance. Our work has an extraodinary meaning for the green preparation and large-scale application of SERS.

Luminol-Eu3+-Gd3+-functionalized mesoporous silica for ultrasensitive detection of tetracycline antibiotics and smartphone-assisted sensing analysis.

An organic-inorganic hybrid nanoprobe, namely LML-D-SBA@Eu3+-Gd3+, was constructed, with SBA-15 acting as the carrier material, and luminol and Eu3+ acting as fluorescence channels to achieve ratiometric signals that eliminate external interference (accurate detection). Gd3+ was used as a sensitizer to amplify the red emission of Eu3+ (ultrasensitive detection). In TCs detection, the luminol emission at 428 nm was quenched due to the photoinduced electron transfer mechanism, and the Eu3+ emission at 617 nm was sensitized due to the synergistic energy transfer from TCs and Gd3+ to Eu3+. The fluorescence intensity at 617 and 428 nm showed ratiometric changes as indicated by notable color changes from blue to red. The detection limits for TC and OTC were 0.21 and 0.08 ng/mL, respectively. To realize a facile, rapid, and cost-effective detection, we constructed a portable intelligent sensing platform based on smartphones, and it demonstrated great potential for on-site detection of TCs.

Tetracycline and fluoroquinolone antibiotics contamination in agricultural soils fertilized long-term with chicken litter: Trends and ravages.

We investigated the potential accumulation of tetracyclines (TCs) such as chlortetracycline (CTC), oxytetracycline (OTC) and doxycycline (DC), and fluoroquinolones (FQs) like enrofloxacin (ENR) and ciprofloxacin (CIP) in chicken litter and agricultural soils fertilized over short-term to long-term (<1-30 yrs) with chicken litter in a poultry hub for the first time from Tamil Nadu, India. CTC, OTC, DC, CIP, and ENR were detected in 46-92 % of the selected chicken litter samples, with mean levels ranging from 2.90 to 23.30 µg kg-1. Higher concentrations of TCs and FQs were observed in freshly collected chicken litter from poultry sheds than in those stockpiled in cultivated lands. CTC was the prevalent antibiotic in chicken litter. The overall occurrence, as well as the ecological risks of TCs and FQs, changed over a 30-yr period. The accumulation of veterinary antibiotics (VAs) (in µg kg-1) in short-term (>1 yr) to medium-term (1-3 yrs) chicken litter-fertilized soils reached a maximum of 11.60 for CTC, 6.50 for OTC, 0.80 for DC, 3.70 for CIP, and 3.60 for ENR, but decreased in long-term (10-30 yrs) fertilized soils. Ecological risk assessment revealed a Risk Quotient (RQ) of ≤0.10 for CTC, OTC, and DC in all soils, while an average risk (RQ >0.10-<1.0) was evident with CIP and ENR in short-term and medium-term fertilized soils. Antibiotic resistance genes (ARGs), including tetA, tetB, qnrA, qnrB and qnrS were detected in most of the chicken litter samples and litter-fertilized soils. Thus, it is critical to develop and adopt effective mitigation strategies before applying chicken litter in farmlands to decrease VAs and ARGs, reducing their associated risks to public health and ecosystems in India considering 'One Health' approach. Future investigations on the occurrence of other VAs and ARGs in soils fertilized with poultry litter at regional scale are required for effective risk mitigation of the widely used VAs.