Application of SCQDs fluorescent probe in field of antibiotic detection
The application of SCQDs fluorescent probes has solved the problem of detecting antibiotic residues in water bodies, achieving high selectivity, low detection limit, and anti-interference ability for tetracycline and levofloxacin, ensuring the accuracy and environmental adaptability of the detection.
Patent Information
- Application Number
- CN202511087594.9
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-08-05
- Publication Date
- 2025-10-31
AI Technical Summary
The extensive use of antibiotics in aquaculture leaves residues in water bodies, leading to ecological pollution and health risks. Existing technologies are insufficient for the efficient and specific detection and monitoring of antibiotic levels in water.
Using SCQDs fluorescent probes, highly selective detection of tetracycline and levofloxacin is achieved through their specific reaction with antibiotics. The fluorescence quenching effect and the switching effect are used to detect these two antibiotics, respectively.
It achieves high sensitivity, low detection limit, and anti-interference ability for the detection of tetracycline and levofloxacin, ensuring the accuracy and environmental adaptability of the detection.
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Figure CN120870078A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of chemical application technology, specifically to the application of an SCQDs fluorescent probe in the field of antibiotic detection. Background Technology
[0002] In current aquaculture, antibiotics are used extensively to prevent bacterial diseases in aquatic animals. However, due to the high frequency of administration and inadequate management systems, antibiotics and their metabolites are often not fully absorbed by aquatic organisms, and some drugs are directly discharged into surrounding waters with aquaculture wastewater. This process results in large amounts of antibiotic residues in aquaculture areas and nearby sea areas, gradually leading to a series of ecological and environmental hazards.
[0003] The administration and accumulation of antibiotics can trigger a series of abnormal physicochemical parameters in water bodies, such as changes in pH, fluctuations in dissolved oxygen concentration, and disruptions in nutrient structure. These abnormalities, in turn, affect the transformation and cycling of substances in the water. As an exogenous selective pressure, antibiotics directly impact the microbial community structure in aquatic bodies. Their broad-spectrum antibacterial effects rapidly reduce or even eliminate some drug-sensitive bacterial species, leading to a decline in microbial diversity and disruption of the original ecological balance. These residues not only alter the physicochemical parameters and microecological structure of the water body but may also suppress sensitive bacterial communities, significantly reduce microbial diversity, and cause imbalances in the microbial community structure.
[0004] Antibiotics can migrate and transform in water bodies through adsorption in sediments and transport by suspended particulate matter, increasing their diffusion and accumulation in the aquatic environment. They can be absorbed by aquatic animals through the food chain and potentially transmitted to humans, posing a public health risk. When water bodies are disturbed by external factors such as tidal changes, antibiotics adsorbed in sediments may be released back into the water, causing "secondary pollution." These pollutants can accumulate at each level of the food chain in aquatic ecosystems. Aquatic animals such as fish and shellfish can absorb antibiotic residues from the water through ingestion or gill absorption, leading to their accumulation in their bodies. If these aquatic products enter the human food system, it may result in excessive antibiotic intake, causing various health problems. Summary of the Invention
[0005] To address the above problems, this invention provides an application of SCQDs fluorescent probes in the field of antibiotic detection.
[0006] In some embodiments, the antibiotics are tetracycline and levofloxacin, wherein tetracycline is detected using an SCQDs-quenched fluorescent probe, and levofloxacin is detected using an SCQDs-Fe... 3+ Switch-type fluorescent probe.
[0007] On the other hand, the present invention provides a method for detecting antibiotics using SCQDs fluorescent probes, wherein the antibiotic is tetracycline or levofloxacin.
[0008] In some embodiments, in the method for detecting antibiotics using SCQDs fluorescent probes of the present invention, the concentration of the SCQDs fluorescent probes is 0.05 mg / mL.
[0009] In some embodiments, in the method for detecting antibiotics using SCQDs fluorescent probes of the present invention, the detection limit of the SCQDs for tetracycline is 270 nM, and the detection limit for levofloxacin is 0.137 μM.
[0010] On the other hand, the present invention provides an SCQDs fluorescent probe detection kit, the kit comprising SCQDs fluorescent probes.
[0011] In some embodiments, the concentration of SCQDs fluorescent probes in the SCQDs fluorescent probe detection kit is 0.05 mg / mL.
[0012] In some embodiments, the SCQDs fluorescent probe detection kit further comprises Fe 3+ The detection.
[0013] In another aspect, the present invention provides the application of the SCQDs fluorescent probe detection kit in the field of antibiotic detection, wherein the antibiotic is preferably tetracycline or levofloxacin.
[0014] The fluorescence intensity of the SCQDs fluorescent probes of this invention significantly decreased upon interaction with tetracycline, but recovered markedly upon interaction with levofloxacin. The addition of coexisting metal ions and antibiotics did not cause significant changes, demonstrating the excellent anti-interference ability of the SCQDs fluorescent probes of this invention. This invention constructed an SCQDs-TC fluorescent probe, utilizing the fluorescence quenching effect of TC on SCQDs to achieve highly selective recognition of TC. This invention constructed an SCQDs-Fe... 3+ -LEV fluorescent switch probe, utilizing LEV to switch Fe 3+ The induced fluorescence quenching recovery effect enables specific detection of LEVs. Attached Figure Description
[0015] Figure 1 The results show the selective detection of different antibiotics by the SCQDs fluorescent probes in Example 2.
[0016] Figure 2 This is the optimized result of the pH tolerance and response time of the SCQDs fluorescent probe in Example 3 during the detection of tetracycline.
[0017] (a) shows the effect of different pH environments on the detection effect of tetracycline, and (b) shows the response time of tetracycline detection.
[0018] Figure 3 The fluorescence response of SCQDs fluorescent probes to tetracycline at different concentrations is shown.
[0019] Figure 4 To detect the anti-interference ability of SCQDs fluorescent probes in the detection of tetracycline.
[0020] Figure 5 For SCQDs-Fe 3+ Results of selective detection of different antibiotics (SD, CEF, SMZ, TC, LEV) by a fluorescent switch.
[0021] Figure 6 For SCQDs-Fe 3+ Optimization results of fluorescent switches for LEV detection conditions.
[0022] (a) Different pH values; (b) Corresponding time.
[0023] Figure 7 For SCQDs-Fe 3+ The detection performance of fluorescent probes for different concentrations of LEV was tested.
[0024] Figure 8 For SCQDs-Fe 3+ Testing the anti-interference performance of fluorescent switch probes for LEV detection. Detailed Implementation
[0025] The present invention will now be described in detail with reference to specific embodiments, but the scope of protection of the present invention is not limited to the following embodiments.
[0026] The instruments and solvents used in this invention are all conventional reagents that can be commercially available.
[0027] Table 1
[0028]
[0029] Table 2
[0030]
[0031] Table 3 lists the experimental instruments and models used in this invention.
[0032] Table 3 Summary of Experimental Instruments
[0033]
[0034] Copper algae: sourced from the copper algae cultivation base in Changdao, Yantai, Shandong.
[0035] Example 1: Preparation of SCQDs Quenched Fluorescent Probes
[0036] (1) Pretreatment of copper algae: The copper algae were repeatedly washed with deionized water 3-4 times, while removing large impurities. The washed copper algae were placed in an oven and dried at 80℃ for 24 hours. After being intermittently pulverized 4 times by a pulverizer, the powder was obtained by sieving through a 100-mesh standard sieve. 0.5g of copper algae powder was placed in a beaker, 50mL of deionized water was added, and the mixture was ultrasonically broken up in an ice bath for 180min, with a 3s interval between ultrasonic treatments to obtain 50mL of copper algae homogenate.
[0037] (2) Preparation of copper diatom-based carbon quantum dots: The copper diatom homogenate (50 mL) prepared above was transferred to a 100 mL tetrafluoroethylene-lined container and placed in a high-pressure reactor for hydrothermal pyrolysis at 220 °C for 18 h. The resulting pyrolysis solution was centrifuged at 10000 r / min for 15 min, and the supernatant was filtered through a 0.22 μm needle filter. The filtrate was then transferred to a 1000 molecular weight dialysis bag and dialyzed for 24 h, with deionized water replaced every 8 h. After dialysis, carbon quantum dot solution (SCQDs) was obtained. The solution was freeze-dried for 48 h to obtain powder, which was then prepared into a 0.05 mg / mL solution with deionized water to obtain a 0.05 mg / mL SCQDs fluorescent probe.
[0038] Example 2: Selective Detection of SCQDs
[0039] Comparative experiments were conducted using cefoxitin (CEF), enrofloxacin (ENR), ciprofloxacin (CIP), levofloxacin (LEV), tetracycline (TC), sulfadiazine (SD), and sulfamethoxazole (SMZ). 1 mL of each of the different antibiotics (500 μmol / L dissolved in deionized water) was added to 1 mL of the SCQDs solution prepared in Example 1. After thorough mixing, the fluorescence intensity was measured. By calculating the fluorescence intensity ratio, the fluorescence response of the SCQDs to different antibiotics was investigated to determine their selectivity.
[0040] Figure 1 The selective detection results of SCQDs fluorescent probes for different antibiotics, including tetracycline, cefoxitin, enrofloxacin, ciprofloxacin, levofloxacin, sulfamethoxazole, and sulfadiazine, were presented. The results showed that SCQDs produced a significant fluorescence quenching effect on tetracycline (significantly decreased F / F0), while exhibiting enhanced fluorescence (significantly increased F / F0) on levofloxacin. The other antibiotics did not cause significant fluorescence changes. This indicates that SCQDs possess a high selective response to tetracycline and levofloxacin, enabling specific recognition in complex environments and demonstrating good application potential.
[0041] Example 3 investigated the effect of pH on the SCQDs fluorescent probe's response to tetracycline (TC).
[0042] The SCQDs prepared in Example 1 and 1 mL of 500 μmol / L tetracycline solution were added sequentially. The effect of pH on the detection system was evaluated by monitoring the changes in fluorescence intensity under different pH conditions (pH of hydrochloric acid or sodium hydroxide solution), thereby determining the optimal pH environment for SCQDs to detect tetracycline. Under the determined optimal pH conditions, 1 mL of 500 μmol / L tetracycline solution was added to 1 mL of SCQDs solution, and the changes in fluorescence intensity were monitored in real time. The fluorescence intensity ratio (F / F0) at different time points was recorded until the signal stabilized, thus determining the optimal response time of the SCQDs fluorescent probe for tetracycline detection.
[0043] Figure 2 This study presents the pH dependence and optimized response time of SCQDs fluorescent probes in tetracycline detection. The results show that the fluorescence quenching ratio (F / F0) of SCQDs varies little under different pH conditions, indicating good pH stability and tolerance for tetracycline detection. Upon addition of tetracycline, the fluorescence intensity of SCQDs decreases rapidly, reaching a steady state within approximately 0.5 seconds, demonstrating its excellent response speed.
[0044] Example 3: Determination of Detection Limit
[0045] Tetracycline standard solutions ranging from 0.01 to 500 μmol / L were prepared. 1 mL of each concentration solution was added sequentially to 1 mL of the SCQDs solution prepared in Example 1. Under 360 nm excitation, the changes in fluorescence intensity were recorded, and the fluorescence intensity ratio (F / F0) was calculated. A working curve was plotted with (F0-F) / F0 as the ordinate and tetracycline concentration as the abscissa. The linear equation and correlation coefficient (R²) were obtained by fitting the curve. 2 Furthermore, the lowest detection limit of SCQDs for tetracycline was estimated based on the formula LOD = 3σ / k (where σ is the standard deviation of the blank sample and k is the slope of the curve).
[0046] Figure 3 The fluorescence response of SCQDs fluorescent probes to tetracycline at different concentrations was demonstrated. As the tetracycline concentration increased from 5 μM to 450 μM, the fluorescence intensity of the SCQDs gradually decreased, exhibiting a significant concentration-dependent quenching effect. Within the low concentration range of 5-100 μM, the fluorescence intensity change was highly linearly correlated with the TC concentration (R0). 2 =0.981), and SCQDs have a detection limit as low as 270 nM for TC, demonstrating excellent trace detection capabilities.
[0047] Example 4 Anti-interference experiment
[0048] To evaluate the interference effect of coexisting substances on the detection of TC by SCQDs fluorescent probes, 1 mL of different coexisting ions (Cd) were taken. 2 +、Hg 2+ Cr 3+ Pb 2 +、Ni 2 +、Co 2+ Cu 2+ Mn 2+ SMZ, CEF, and SD (all at a final concentration of 500 μM / L) and common antibiotics (SMZ, CEF, and SD, each at a concentration of 500 μM / L) were added sequentially to a mixed solution of 1 mL SCQDs and 1 mL 500 μM / L tetracycline. After thorough mixing, the fluorescence intensity was measured, and the fluorescence intensity ratio (F / F0) was calculated to systematically analyze the potential interference of coexisting substances on the detection of tetracycline by the SCQDs probe.
[0049] Figure 4 The study demonstrated the anti-interference ability of SCQDs fluorescent probes in the detection of tetracycline. Results showed that the fluorescence intensity of SCQDs decreased significantly upon the addition of tetracycline, while it remained relatively stable in the presence of multiple metal ions (Hg). 2+ Cr 3+ Pb 2 +、Ni 2 +、Co 2 + Cu 2+ Mn 2+ Under conditions of coexisting substances and other antibiotics (SMZ, CEF, SD), the fluorescence intensity remained stable without significant changes. This indicates that the coexisting substances did not significantly interfere with the specific fluorescence quenching process between SCQDs and tetracycline. This result demonstrates that SCQDs possess excellent anti-interference capabilities and can achieve highly selective detection of tetracycline in complex environments, further validating their reliability and application potential in actual water sample analysis (Blank group had an equal volume of water added).
[0050] Example 5: Selective Detection of Levofloxacin (LEV)
[0051] Prepare 500 μmol / L solutions of LEV and other control antibiotics (SD, CEF, SMZ, and TC, each with a concentration of 500 μmol / L). Add 2 mL of SCQDs-Fe... 3+ Probe solution (1 mL of SCQDs prepared in Example 1, Fe) 3+Add 1 mL of 500 μmol / L antibiotic solution to each of the 1 mL solutions (500 μmol / L), mix well, and react at room temperature for 1 h. Record the ratio of fluorescence intensity change (F / F0). The selectivity of the probe is evaluated by comparing the fluorescence recovery effect of LEV with that of other antibiotics.
[0052] Figure 5 SCQDs-Fe were demonstrated 3+ The fluorescence switch selectively detected different antibiotics (SD, CEF, SMZ, TC, LEV). Only after the addition of LEV did the fluorescence intensity (F / F0) increase significantly, while other antibiotics showed no significant effect, indicating that the probe has high specificity for LEV and achieves an "OFF-ON" switching effect.
[0053] Example 6
[0054] Optimal pH Study
[0055] Phosphate-buffered saline (PBS) solutions with pH ranges of 4–10 were prepared, and SCQDs-Fe were measured under different pH conditions (4, 5, 6, 7, 8, 9, 10). 3+ Probe (1 mL of SCQDs prepared in Example 1, Fe) 3+ The fluorescence change of 500 μmol / L (1 mL) against 500 μmol / L LEV was recorded. The fluorescence intensity recovery ratio (F / F0) was recorded to determine the optimal pH conditions for the probe.
[0056] Response time
[0057] Add 2 mL of SCQDs-Fe 3+ Probe solution (SCQDs 1mL, Fe) 3+ Add 1 mL of 500 μmol / L LEV to 1 mL of 500 μmol / L solution, record the fluorescence intensity changes from 0 to 60 min, and determine the optimal response time of the probe.
[0058] Figure 6 The text describes SCQDs-Fe. 3+ The results of optimizing the conditions for LEV detection using a fluorescence switch were presented. pH effects experiments showed that the probe exhibited the most significant fluorescence enhancement within the pH range of 7-8, with the optimal pH being 8. After the addition of LEV, the fluorescence intensity recovered within 30 seconds and stabilized within approximately 30 minutes. Therefore, this probe demonstrates optimal detection performance under neutral conditions, exhibiting good sensitivity and stability, and can be used for efficient LEV detection.
[0059] Example 7: Determination of Detection Limit
[0060] Take 2 mL of SCQDs-Fe 3+Probe solution (1 mL of SCQDs prepared in Example 1, Fe) 3+ Different concentrations of LEV (0.01-500 μmol / L) were added to the probe at 500 μmol / L per mL. The fluorescence spectra were recorded after reacting at room temperature for 1 h. The fluorescence intensity change (F-F0) was calculated, and a standard curve of fluorescence intensity change versus LEV concentration was plotted. The LOD of the probe was determined using the 3σ / k calculation method to quantify its detection sensitivity.
[0061] Figure 7 SCQDs-Fe were demonstrated 3+ The detection performance of the fluorescent probe for different concentrations of LEV was evaluated. As the LEV concentration increased from 10 μmol / L to 500 μmol / L, the fluorescence intensity significantly increased, exhibiting a concentration-dependent fluorescence recovery phenomenon. Linear fitting results showed that within the range of 0.01–100 μM, the change in fluorescence intensity (F–F0) had a good linear relationship with the LEV concentration (R0). 2 =0.997). The calculated limit of detection is 0.137 μM, which is far superior to traditional detection methods, indicating that the probe has high sensitivity and excellent linear response.
[0062] Example 8 Anti-interference performance test
[0063] Five metal ions (Hg) were selected 2+ K + Pb 2 +、Mn 2+ Cr 3+ SCQDs-Fe (each substance at a concentration of 500 μmol / L) and three antibiotics (SD, CEF, and SMZ, each at a concentration of 500 μmol / L) were identified as potential interfering agents. 3+ In the probe solution (500 μmol / L), each coexisting substance was added at equal concentrations and the fluorescence changes were recorded.
[0064] Figure 8 SCQDs-Fe were demonstrated 3+ The anti-interference performance of the fluorescent switch probe for LEV detection. Addition of other coexisting metal ions (Hg) 2+ K + Pb 2 +、Mn 2+ Cr 3+ After adding antibiotics (SMZ, CEF, SD), the fluorescence recovery efficiency (F / F0) of the probe remained almost unchanged compared to adding only LEV (Blank, which is an equal volume of water), maintaining a high level. This indicates that SCQDs-Fe 3+ The fluorescent switch probe exhibits good selectivity for LEVs and excellent anti-interference capabilities.
Claims
1. Application of an SCQD fluorescent probe in the field of antibiotic detection.
2. The application of the SCQDs fluorescent probe according to claim 1 in the field of antibiotic detection, characterized in that, The antibiotic is tetracycline or levofloxacin, wherein the detection of tetracycline is performed using an SCQDs quenching fluorescent probe, and the detection of levofloxacin is performed using a switch-type SCQDs fluorescent probe.
3. A method for detecting antibiotics using SCQDs fluorescent probes, characterized in that, The antibiotic is tetracycline or levofloxacin.
4. The method for detecting antibiotics using SCQDs fluorescent probes according to claim 3, characterized in that, The concentration of the SCQDs fluorescent probe is 0.05 mg / mL.
5. The method for detecting antibiotics using SCQDs fluorescent probes according to claim 3, characterized in that, The SCQDs have a detection limit of 270 nM for tetracycline and a detection limit of 0.137 μM for levofloxacin.
6. A fluorescent probe detection kit for SCQDs, characterized in that, The kit includes SCQD fluorescent probes.
7. The SCQDs fluorescent probe detection kit according to claim 6, characterized in that, The concentration of the SCQDs fluorescent probe is 0.05 mg / mL.
8. The SCQDs fluorescent probe detection kit according to claim 6, characterized in that, The kit further includes Fe 3+ .
9. The application of the SCQDs fluorescent probe detection kit according to any one of claims 6-8 in the field of antibiotic detection, wherein the antibiotic is preferably tetracycline or levofloxacin.