RESUMO
Herein, a novel bimodal ratiometric probe for sensitive and selective detection of biothiols (including glutathione (GSH), cysteine (Cys) and homocysteine (Hcys)) was constructed, which was based on the redox reaction between manganese dioxide nanoflakes (MnO2 NFs) and rhodamine (RhB) and biothiols. When MnO2 NFs was added into RhB solution, RhB was oxidized to a series of derivatives, accompanying with the colorimetric color changing from purple to light pink and fluorescence changing from red to green. In the presence of GSH, Cys or Hcys, they could reduce MnO2 NFs to Mn2+, thereby preventing the following oxidization of RhB and the corresponding color and fluorescence changes. The absorption intensity ratio and fluorescence intensity ratio showed good linear relationships with the concentrations of biothiols. The colorimetric detection limits for GSH, Cys and Hcys were 0.057 µM, 0.140 µM and 0.087 µM, respectively. And the fluorescence detection limits were 0.177 µM, 0.282 µM and 0.161 µM. More importantly, this probe was successfully applied to monitor the concentration of GSH/Cys/Hcys in human serum samples, with satisfactory recovery. Thus, this MnO2 NFs-RhB platform can potentially be a candidate for the detection of biothiols.
Assuntos
Colorimetria , Compostos de Manganês , Cisteína , Corantes Fluorescentes , Glutationa , Homocisteína , Humanos , Óxidos , Rodaminas , Espectrometria de FluorescênciaRESUMO
Three-dimensional carbon-based porous materials have proven to be quite useful for tailoring material properties in the energy conservation and environmental protection applications. In view of the three-dimensional and well-defined structure of metal-organic frameworks (MOFs), a novel carbon-based magnetic porous material (HKUST-Fe3O4) has been designed and constructed by MOF-guest interactions of high-temperature pyrolysis. The obtained HKUST-Fe3O4 exhibited the unique features of superparamagnetism, a macro/mesoporous structure, environmental protection (inexistence of toxic heavy metal ions), and physicochemical stability and has shown high adsorption capacity and rapid adsorption for carcinogenic organic pollutants (for example, rhodamine B) with an environmentally friendly character and excellent reusability. We demonstrate that the unique/superior advantages of HKUST-Fe3O4 could meet the requirements of environment cleaning, especially for removing the targeted organic pollutant from water. Moreover, the specific HKUST-Fe3O4 and organic pollutant interaction mechanism has been analyzed in detail via parameter-free calculations. This study proposes a promising strategy for constructing novel carbon-based magnetic nanomaterials for various applications, not limitated to pollutant removal.
RESUMO
Mercury (II) ions (Hg2+), as one of the most toxic heavy metals, can cause irreversible damage to human health even at very low concentration due to its high toxicity and bioaccumulation. Herein, a facile ratiometric fluorescence nanomixture based on carbon dotsgold nanoclusters (CDs-Au NCs) was constructed for quantitative detection of Hg2+. Lysine functionalized carbon dots (CDs) were prepared by one-pot hydrothermal method, while gold nanoclusters (Au NCs) were synthesized via using chicken egg white (CEW) as reducer and stabilizer. The novel nanomixture exhibited two strong emission peaks at 450â¯nm and 665â¯nm under 390â¯nm excitation, and showed pink fluorescence under UV light. Interestingly, the fluorescence of the CDs-Au NCs nanomixture was selectively response to Hg2+. The fluorescence of Au NCs at 665â¯nm was decreased when Hg2+ was presented in the solution, while the fluorescence of CDs at 450â¯nm stayed constant. The fluorescence color changed from pink to blue obviously with increasing the concentration of Hg2+, which indicated that CDs-Au NCs could be used for visual detection Hg2+ by the naked eye. Under optimal conditions, this ratiometric fluorescent sensor could detect Hg2+ accurately and possess a great sensitivity with a detection limit of 63â¯nM. In addition, this method was applied to detect Hg2+ in real water samples with great recoveries, suggesting its potential in practical application with simplicity, environmentally friendly and low cost.
RESUMO
The wide use of tetracyclines (TCs) for prevention and therapy of animal diseases may result in excessive residues in animal products, which could pose serious risks to human health. A novel molybdenum disulfide nanoplates (MoS2 NPs)-based fluorescent sensor for tetracycline (TET) is reported. The MoS2 NPs, synthesized via a facile bottom-up hydrothermal route, showed blue fluorescence at 430â¯nm in aqueous solution. Interestingly, its fluorescence was quenched significantly upon addition of TET, which is mainly due to a combination of the inner filter effect and electron transfer. Thus, the MoS2 NPs based fluorescence sensor was delineated for the detection of TET. The methodology here presented showed a low detection limit of 0.032⯵M and satisfied recoveries from 88.46% to 108.62% in spiked milk, milk powder and bovine muscle samples.