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Surface-enhanced Raman scattering method for the identification of methicillin-resistant Staphylococcus aureus using positively charged silver nanoparticles
摘要： The article describes a SERS-based method for diagnosis of bacterial infections. Positively charged silver nanoparticles (AgNPs+) were employed for identification of methicillin-resistant Staphylococcus aureus (MRSA). It is found that AgNPs+ undergo self-assembly on the surface of bacteria via electrostatic aggregation. The assembled AgNPs+ are excellent SERS substrates. To prove the capability of SERS to differentiate between S. aureus and other microorganisms, six standard strains including S. aureus 29213, S. aureus 25923, C. albicans, B. cereus, E. coli, and P. aeruginosa were tested. To further demonstrate its applicability for the identification of MRSA in clinical samples, 52 methicillin-sensitive S. aureus (MSSA) isolates and 215 MRSA isolates were detected by SERS. The total measurement time (include incubation) is 45 min when using a 3 μL sample. The method gives a strongly enhanced Raman signal (at 730 cm?1 and 1325 cm?1) with good reproducibility and repeatability. It was successfully applied to the discrimination of the six strain microorganisms. The typical Raman peaks of S. aureus at 730, 1154, 1325, and 1457 cm?1 were observed, which were assigned to the bacterial cell wall components (730 cm?1- adenine, glycosidic ring mode, 1154 cm?1- unsaturated fatty acid, 1325 cm?1- adenine, polyadenine, and 1457 cm?1 for -COO- stretching). S. aureus was completely separated from other species by partial least squares discriminant analysis (PLS-DA). Moreover, 52 MSSA isolates and 215 MRSA isolates from clinical samples were identified by PLS-DA. The accuracy was almost 100% when compared to the standard broth microdilution method. A classification based on latent structure discriminant analysis provided spectral variability directly. Conceivably, the method offers a potent tool for the identification of bacteria and antibiotics resistance, and for studies on antibiotic-resistance in general.
关键词： S. aureus,Nanoparticles,Methicillin resistance,Antibiotics,Latent structure discriminant analysis classification (OPLS-DA),SERS,Partial least squares discriminant analysis (PLS-DA),AgNPs,Discriminant analysis,Raman spectroscopy
更新于2025-09-23 15:22:29
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The surgical wound in infrared: thermographic profiles and early stage test-accuracy to predict surgical site infection in obese women during the first 30?days after caesarean section
摘要： Background: Prophylactic antibiotics are commonly prescribed intra-operatively after caesarean section birth, often at high doses. Even so, wound infections are not uncommon and obesity increases the risk. Currently, no independent wound assessment technology is available to stratify women to low or high risk of surgical site infection (SSI). Study Aim: to investigate the potential of non-invasive infrared thermography (IRT), performed at short times after surgery, to predict later SSI. Methods: IRT was undertaken in hospital on day 2 with community follow up (days 7, 15, 30) after surgery. Thermal maps of wound site and abdomen were accompanied by digital photographs, the latter used for wound assessment by six experienced healthcare professionals. Confirmatory diagnosis of SSI was made on the basis of antibiotic prescribing by the woman’s community physician with logistic regression models derived to model dichotomous outcomes. Results: Fifty-three women aged 21–44 years with BMI 30.1–43.9 Kg.m? 2 were recruited. SSI rate (within 30 days) was 28%. Inter-rater variability for ‘professional’ opinion of wound appearance showed poor levels of agreement. Two regions of interest were interrogated; wound site and abdomen. Wound site temperature was consistently elevated (1.5 °C) above abdominal temperature with similar values at days 2,7,15 in those who did and did not, develop SSI. Mean abdominal temperature was lower in women who subsequently developed SSI; significantly so at day 7. A unit (1 °C) reduction in abdominal temperature was associated with a 3-fold raised odds of infection. The difference between the sites (wound minus abdomen temperature) was significantly associated with odds of infection; with a 1 °C widening in temperature associated with an odds ratio for SSI of 2.25 (day 2) and 2.5 (day 7). Correct predictions for wound outcome using logistic regression models ranged from 70 to 79%; Conclusions: IRT imaging of wound and abdomen in obese women undergoing c-section improves upon visual (subjective) wound assessment. The proportion of cases correctly classified using the wound-abdominal temperature differences holds promise for precision and performance of IRT as an independent SSI prognostic tool and future technology to aid decision making in antibiotic prescribing.
关键词： Antibiotics,Caesarean section,Obesity,Surgical site infection,Infrared thermography,Prognosis,Thermal mapping
更新于2025-09-23 15:22:29
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White-Light-Emitting Decoding Sensing for Eight Frequently-Used Antibiotics Based on a Lanthanide Metal-Organic Framework
摘要： Developing multi-selective luminescence sensing technology to differentiate serial compounds is very important but challenging. White-light-emitting decoding sensing based on lanthanide metal-organic frameworks (Ln-MOFs) is a promising candidate for multi-selective luminescence sensing application. In this work, three isomorphic Ln-MOFs based on H3dcpcpt (3-(3,5-dicarboxylphenyl)-5-(4-carboxylphenl)-1H-1,2,4-triazole) ligand, exhibiting red, blue, and green emission, respectively, have been synthesized by solvothermal reactions. The isostructural mixed Eu/Gd/Tb-dcpcpt is fabricated via the in-situ doping of different Ln3+ ions into the host framework, which can emit white light upon the excitation at 320 nm. It is noteworthy that this white-light-emitting complex could serve as a convenient luminescent platform for distinguishing eight frequently-used antibiotics: five through luminescence-color-changing processes (tetracycline hydrochloride, yellow; nitrofurazone, orange; nitrofurantoin, orange; sulfadiazine, blue; carbamazepine, blue) and three through luminescence quenching processes (metronidazole, dimetridazole, and ornidazole). Moreover, a novel method, 3D decoding map, has been proposed to realize multi-selective luminescence sensing applications. This triple-readout map features unique characteristics on luminescence color and mechanism. The mechanism has been systematically interpreted on the basis of the structural analysis, energy transfer and allocation process, and peak fitting analysis for photoluminescence spectra. This approach presents a promising strategy to explore luminescent platforms capable of effectively sensing serial compounds.
关键词： lanthanide,metal-organic framework,multi-selective luminescence sensing,decoding sensing,white light,antibiotics
更新于2025-09-23 15:22:29
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Binary-phase TiO2 modified Bi2MoO6 crystal for effective removal of antibiotics under visible light illumination
摘要： A series of binary-phase TiO2 modified Bi2MoO6 nanocrystals have been prepared via a solvothermal-calcination process. Trace TiO2 modification can effectively enhance the visible light catalytic activity of Bi2MoO6 to remove the antibiotics in aqueous solution. The obtained TiO2/Bi2MoO6 composites were investigated by some physicochemical techniques like XRD, N2 adsorption, SEM, TEM, UV–vis DRS, Raman, XPS, PL and Photo-electrochemical measurement. The presence of TiO2 nanoparticles (NPs) influenced the crystal growth of Bi2MoO6, decreasing the crystal size of Bi2MoO6 and effectively promoting its specific surface area. Moreover, the conduction band of TiO2 can serve as the electron transfer platform, which largely boosts the effective separation of photocarriers at TiO2/Bi2MoO6 heterojunction interface. With optimal TiO2 content (0.41 wt%), TiO2/Bi2MoO6 exhibited the best photocatalytic performance for different antibiotics degradation, e.g. ciprofloxacin, tetracycline and oxytetracyline hydrochloride under visible light irradiation. Moreover, the mechanism for enhanced photocatalytic performance in ciprofloxacin degradation was illuminated.
关键词： Mechanism,Binary-phase TiO2,Antibiotics,Photocatalytic degradation,Bi2MoO6
更新于2025-09-23 15:22:29
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Multi-dimensional fluorescence spectroscopy coupled with chemometrics in rapid antibiotic detection and discrimination
摘要： Antibiotic residues in animal-derived foods pose risk to human health including chemical poisoning and antimicrobial resistance, and therefore, constant monitoring throughout the food supply chain is important. In the present study multi-dimensional fluorescence spectroscopy (3D and 2D) coupled with chemometric tools were tested for potential application to detect, discriminate and quantify penicillin G (PG), sulfadiazine (SF) and tetracycline (TC) in milk by direct measurement. Qualitative and quantitative calibration models were developed for prediction of antibiotic residues. Results demonstrated optimal discrimination of milk samples on the basis of antibiotic type and concentration with close to 100% of accuracy. Negative correlation between antibiotic concentration and fluorescence peak height was displayed (r ≥ 0.963 and p ≤ 0.002). A great potential for quantitative antibiotic determination was established with R2 > 0.9 and low standard errors of estimation indicating acceptable precision for the developed technique. Fluorescence spectroscopy demonstrated high specificity and sensitivity with detection limit below the maximum residue limit of PG, SF and TC in milk. Therefore, fluorescence spectroscopy can be used as an alternative method for rapid screening of antibiotic residues in milk at collection centers and processing plants to ensure product quality and safety.
关键词： Rapid detection,Antibiotics,Discrimination,Fluorescence spectroscopy,Milk
更新于2025-09-23 15:19:57
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Rapidly detecting antibiotics with magnetic nanoparticle coated CdTe quantum dots
摘要： A reusable magnetic-quantum dot material (MNP–SiO2–QD) with good magnetic properties and high ?uorescence retention was successfully fabricated from linked magnetic nanoparticles and quantum dots. The resulting material can qualitatively and quantitatively detect four kinds of antibiotics and maintain high recovery rates.
关键词： reusability,antibiotics detection,fluorescence,magnetic nanoparticles,quantum dots
更新于2025-09-23 15:19:57
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Fiberoptic-Coupled Spectrofluorometer with Array Detection as a Process Analytical Chemistry Tool for Continuous Flow Monitoring of Fluoroquinolone Antibiotics
摘要： Nowadays, there is an increasing need for sensitive real-time measurements of various analytes and monitoring of industrial products and environmental processes. Herein, we describe a ?uorescence spectrometer in continuous ?ow mode in which the sample is fed to the ?ow cell using a peristaltic pump. The excitation beam is introduced to the sample chamber by an optical ?ber. The ?uorescence emitted upon excitation is collected at the right angle using another optical ?ber and then transmitted to the ?uorescence spectrometer which utilizes an array detector. The array detection, as a key factor in process analytical chemistry, made the ?uorescence spectrometer suited for multiwavelength detection of the ?uorescence spectrum of the analytes. After optimization of the experimental parameters, the system has been successfully employed for sensitive determination of four ?uoroquinolone antibiotics such as cipro?oxacin, o?oxacin, levo?oxacin, and moxi?oxacin. The linear dynamic ranges of four ?uoroquinolones were between 0.25 and 20 μg·mL? 1, and the detection limit of the method for cipro?oxacin, o?oxacin, levo?oxacin, and moxi?oxacin were 81, 36, 35, and 93 ng·mL? 1, respectively. Finally, the proposed system is carried out for determination of ?uoroquinolones in some pharmaceutical formulations.
关键词： Fluoroquinolone antibiotics,Fiberoptic-coupled spectrofluorometer,Process Analytical Chemistry,Continuous flow monitoring,Array detection
更新于2025-09-19 17:13:59
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Rapid screening and quantification of multi-class antibiotic pollutants in water using a planar waveguide immunosensor
摘要： Rapid screening and quantification of multi-class antibiotic pollutants in water using a planar waveguide immunosensor
关键词： immunosensor,antibiotics,planar waveguide,detection,water
更新于2025-09-16 10:30:52
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Enhanced photocatalytic degradation of antibiotics in water over functionalized N,S-doped carbon quantum dots embedded ZnO nanoflowers under sunlight irradiation
摘要： ZnO is widely used as a photocatalyst in industry, however, it is still a challenge to degrade refractory antibiotics in water. In this study, a novel surface-functionalized N,S-doped carbon quantum dot (N,S-CQD) was synthesized and embedded into ZnO for the formation of a new ZnO/N,S-CQDs hybrid nanoflower via one-pot hydrothermal process. The as-prepared ZnO/N,S-CQDs showed significantly enhanced photocatalytic activity under visible and near-infrared (NIR) light irradiation, in which 72.8% of MG was decomposed after 180 min under NIR light. In addition, approximately 92.9% and 85.8% of ciprofloxacin (CIP) were degraded by ZnO/N,S-CQDs under simulated sunlight for 20 min and natural sunlight for 50 min, respectively. Furthermore, the mechanism was investigated and the results show that the surface functionalization, electron transfer, up-converted luminescence properties of N,S-CQDs, together with the highly reactive facets of ZnO nanoflowers, made great contributions to the enhanced photocatalytic activity of ZnO/N,S-CQDs. Additionally, the results of active species trapping experiments indicated that the hydroxide free radicals, holes and superoxide radical anions all played certain roles in the photocatalytic reaction. Finally, ZnO/N,S-CQDs was employed for photodegradation of antibiotics in actual water, the degradation efficiency of antibiotics still remained above 60% after 120 min. We believe that the ZnO/N,S-CQDs nanoflower is a promising photocatalyst for the degradation of refractory antibiotics under sunlight irradiation. The relatively low cost and excellent photocatalytic performance of ZnO/N,S-CQDs is beneficial for industrial applications.
关键词： antibiotics,carbon quantum dots,ZnO nanoflowers,photocatalysis,sunlight irradiation
更新于2025-09-16 10:30:52
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Core-shell hollow spheres of type C@MoS2 for use in surface-assisted laser desorption/ionization time of flight mass spectrometry of small molecules
摘要： Mesoporous carbon hollow spheres coated with MoS2 (C@MoS2) were synthesized to obtain a material with large specific surface area, fast electron transfer efficiency and good water dispersibility. The composite material was applied as a matrix for the analysis of small molecules by surface-assisted laser desorption/ionization time-of-flight mass spectrometry (SALDI-TOF MS). The use of a core-shell C@MoS2 matrix strongly reduces matrix background interferences and increases signal intensity in the analysis of sulfonamides antibiotics (SAs), cationic dyes, emodin, as well as estrogen and amino acids. The composite material was applied to the SALDI-TOF MS analysis of selected molecules in (spiked) real samples. The ionization mechanism of the core-shell C@MoS2 as a matrix is discussed. The method exhibits low fragmentation interference, excellent ionization efficiency, high reproducibility and satisfactory salt tolerance.
关键词： Ionization mechanism,Core-shell C@MoS2,Emodin,Estrogen,Amino acids,Cationic dyes,Sulfonamides antibiotics,SALDI-TOF MS,Salt tolerance
更新于2025-09-12 10:27:22