ABSTRACT
Objective@#The effect and mechanism of cadmium telluride quantum dots (CdTe QDs) on cytochrome P450 (CYP450) in the liver of rat were investigated.@*Methods@#CdTe QDs (Ex 350 nm, Em 600 nm) were incubated with microsomes in final concentrations (0.5, 5, 50 μmol/L) using rat liver. And the content of CYP450 was determined by mixed incubation system as time (15, 30, 45 min) went on. Relationship also was detected between particle sizes (Em 620, 580, 540 nm; CdTe QDs-2, CdTe QDs-3, CdTe QDs-4) and expression of CYP450. Twenty male Wistar rats were randomly divided into exposed groups at various concentrations (0.25, 2.5 and 12.5 μmol/kg) of CdTe QDs via tail vein injection, the control group was injected with PBS.@*Results@#In vitro, CdTe QDs(0.5, 5, 50 μmol/L) could significantly increase the content of CYP450 in rat liver microsomes(P<0.05), which increased first and then decreased with the dose adding. Moreover, the trend along with the exposure time (15, 30, 45 min) was the same as that in dosages at certain concentration (P<0.01). For different particle sizes, the smaller CdTe QDs were, the higher content increased, the content of CYP450 in group CdTe QDs-4 was the highest (P<0.05). In vivo, experiment proved that CdTe QDs (0.25, 2.5 and 12.5 μmol/kg) could obviously induce the expression of CYP450 (P<0.01). The content level showed a tendency to rise and then fall.@*Conclusion@#CdTe QDs could promote the content of CYP450 in rat liver microsomes, it indicated that CdTe QDs had dose-effect relationship both in vivo and vitro. There was a certain relationship in time-effect. In addition, the smaller particle size was, the greater impact had.
ABSTRACT
Mycobacterium tuberculosis, the causing agent of tuberculosis, comes second only after HIV on the list of infectious agents slaughtering many worldwide. Due to the limitations behind the conventional detection methods, it is therefore critical to develop new sensitive sensing systems capable of quick detection of the infectious agent. In the present study, the surface modified cadmium-telluride quantum dots and gold nanoparticles conjunct with two specific oligonucleotides against early secretory antigenic target 6 were used to develop a sandwich-form fluorescence resonance energy transfer-based biosensor to detect M. tuberculosis complex and differentiate M. tuberculosis and M. bovis Bacille Calmette–Guerin simultaneously. The sensitivity and specificity of the newly developed biosensor were 94.2% and 86.6%, respectively, while the sensitivity and specificity of polymerase chain reaction and nested polymerase chain reaction were considerably lower, 74.2%, 73.3% and 82.8%, 80%, respectively. The detection limits of the sandwich-form fluorescence resonance energy transfer-based biosensor were far lower (10 fg) than those of the polymerase chain reaction and nested polymerase chain reaction (100 fg). Although the cost of the developed nanobiosensor was slightly higher than those of the polymerase chain reaction-based techniques, its unique advantages in terms of turnaround time, higher sensitivity and specificity, as well as a 10-fold lower detection limit would clearly recommend this test as a more appropriate and cost-effective tool for large scale operations.
Subject(s)
Humans , Biosensing Techniques/methods , Mycobacterium bovis/isolation & purification , Mycobacterium tuberculosis/isolation & purification , Sputum/microbiology , Tuberculosis, Pulmonary/diagnosis , Cadmium Compounds , Fluorescence Resonance Energy Transfer/instrumentation , Fluorescence Resonance Energy Transfer/methods , Gold , Metal Nanoparticles , Polymerase Chain Reaction , Reproducibility of Results , Sensitivity and Specificity , TelluriumABSTRACT
A novel method for the detection of moroxydine ( ABOB) residue in tomatoes was developed based on the enhancement of the fluorescence intensity of CdTe quantum dots( QDs) in the presence of ABOB. The factors influencing the performance of the QDs fluorescent probes were investigated, and the optimum conditions were determined:the concentration of mercaptoacidic acid ( TGA) capped-CdTe quantum dot was 1×10-4 mol/L, and the reaction time was 20 min at pH=5. 6. Under the optimum conditions, the relative fluorescence intensity increases linearly proportional to the ABOB concentration in the range of 1. 0×10-12-5. 0×10-10 mol/L with a limit of detection of 5. 2×10-13 mol/L, R=0. 9981, the recovery was 97%-106%, without obvious interference on the determinations of moroxydine from the common coexisting ions, antibiotics, and vitamins. The proposed method has been successfully applied in the detection of trace moroxydine hydrochloride residue in tomatoes.