A new method for detection ofToxoplasma gondiivia DNA sensing technology was developed in this study. It was based on the mechanism of fluorescence resonance energy transfer (FRET) in which multifunctional and magnetic-fluorescent CdTe@Ni quantum dots (mQDs) were utilized as energy donor and a commercial BHQ2as acceptor. The sensing probe was fabricated by labeling a stem-loopToxoplasma gondiiDNA oligonucleotide with CdTe@Ni mQDs at the 5′ end and BHQ2at 3′ end, respectively. The surface assembly of CdTe on Ni core and the formation of CdTe@Ni were confirmed by XRD analysis. The sizes of CdTe, Ni nanoparticles, and CdTe@Ni were measured via TEM and XRD methods and estimated to be~3 nm,~15 nm, and~20 nm, respectively. The sensing ability was investigated by the fluorescence spectrum (FS). An obvious fluorescence recovery was observed when the complete complimentary targetToxoplasma gondiiDNA was introduced, which did not happen in the case of the target DNA with one-base pair mismatch. Our research indicates that the current sensing probe is sensitive and specific in detection ofToxoplasma gondiiDNA and has great potential in Toxoplasmosis diagnosis.
The core-shell CdTe/ZnS quantum dots were prepared with an improved process in aqueous phase. CdTe QDs were synthesized under conditions of pH 9.1, 96 °C, refluxing for 5h, and which was used as core material; ZnS was formed as shell material to enhance the optical properties. Optical properties were characterized with fluorescence spectrum (FS), and morphology of QDs was investigated via transmission electron microscopy (TEM) method. Moreover, composition and formation of CdTe/ZnS core-shell QDs was characterized via x-ray diffraction (XRD) method. Optimum conditions were investigated to obtain the qualified CdTe/ZnS core-shell QDs, the results indicated QDs with high quantum yields and fluorescence intensity were achieved under conditions of pH 9.0, 45 °C, refluxing for 1h, and v/v/v ratio of CdTe/Na2S/ZnSO4 is 4/1/1. The TEM data indicated that average size of 5 nm CdTe core was prepared, and CdTe/ZnS core-shell QDs with average size of 11 nm were achieved under the optimum conditions. ca 30nm of red shift of a maximum emission wavelength from ca 530 nm (CdTe) to 560 nm (CdTe/ZnS) was observed via FS under the optimum conditions, which inferred the growth of QDs and formation of ZnS shells. Furthermore, the enhanced fluorescence intensity of CdTe/ZnS core-shell QDs was detected and over two times of fluorescence intensity was increased after formation of ZnS shell. The obtained QDs will have great potential application in biological researches and biosensing system based on fluorescence resonance energy transition (FRET).
Hydrotalcites known as anionic clays are found in nature. Hydrotalcites, hydrotalcite-like compounds, and calcined hydrotalcites (as mixed or complex oxides) as highly active, selective catalysts play an important role in many base/catalyzed reactions. Mg/Al hydrotalcite (MAH) as precursor was used to prepare Mg/Al metal complex oxides (MAO), used as epoxidation catalysts in the current research. In this paper, some primary physical and catalytic properties of MAH and MAO were investigated. The results indicated that the qualified MAH (Mg/Al mol ratio of 3) can be achieved when the suspension was crystallized under 80°C for 16h, and after being filtered, dried at 100 °C for 5h in a oven. MAO was prepared by calcining MAH for 4h in a muffle furnace, and calcination temperature was determined to be 500 °C by a differential scanning calorimeter (DSC). Crystal structure and parameters of MAH and MAO were characterized by X/ray diffraction (XRD), good crystal structure was observed and typical peaks of MAH were detected when 2θ was at 11.5 (003), 23.0 (006), 35.0 (009), and 61.0 (110), respectively. The morphology of calcined precursor, i.e. MAO, was investigated with scanning electron microscopy (SEM); the finer lamellar structure and smaller average size of 3μm was observed. Molding research was performed and confirmed by SEM, the results indicated that the surface bulge and cavity with size of several micrometers were increased, which simultaneously suggested the increasing of specific surface area. The catalytic activity of molding MAO was finally examined by using octanol as starting reagent and ethylene oxide as reactant, and narrower molecular distribution was observed comparing with the traditional catalyst-KOH
Quantum dots (QDs) are normally based on the semiconductor materials and widely used in biosensing, bioimaging, biolabeling, and biotreatment for their excellent properties. The ecotoxicity research of QDs correspondingly kept in rising in recent years. CdTe and CdTe/ZnS QDs were prepared via an improved process in aqueous phase, morphology of QDs was characterized with transmission electron microscopy, and optical properties were investigated via fluorescence spectrum. Ecotoxicity of CdTe and CdTe/ZnS were assayed by measuring the inhibitory growth of Rhodococcus sp. strain C1 when QDs existed in broth culture, which was screened from sewage, and its morphology was characterized with optical microscope and scanning electron microscope. CdTe QDs showed strong inhibitory effect against growth of Rhodococcus sp. strain C1, and little growth was observed after 72h cultivation. CdTe/ZnS QDs showed prophasic inhibition before 36h, and growth recovery was observed after 48h of cultivation. Enhanced optical properties and decreasing ecotoxicity were validated after ZnS shell formation, these results indicated that CdTe/ZnS QDs with core-shell structure has great potential in bio-applications.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
customersupport@researchsolutions.com
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.