Fluorescent Nanoprobes Confined in a Drop as a novel Sensing Platform for Detection of Metal Species at Trace Level
Poster Mar 11, 2015
Carlos Bendicho, Isabel Costas-Mora, Vanesa Romero, Isela Lavilla
In this work, fluorescent quantum dots (QDs) and gold nanoclusters (Au NCs) are confined in a drop to develop a novel sensing platform for metal ions and organometals at trace level (detection limits in the range of micro-to-nano molar). A portable micro-fluorospectrometer was employed for fluorescence measurement.
CdSe and core-shell CdSe/ZnS QDs were stabilized with hexadecylamine (HDA) and dispersed in an organic drop (n-octane, decane). Metal species were incorporated into the sensing drop following headspace single-drop microextraction. This integrated system allows the isolation of the target analyte, its preconcentration and recognition in a smart way. Advantages of the novel approach include increased selectivity (phase separation removes potential matrix effects) and sensitivity as well as low consumption of nanoprobes. Consequently, the generation of toxic wastes due to elements contained in the QD composition (e.g. Cd, Se) is kept to a minimum. In addition, no functionalization of the nanoprobes is required, their dispersion in the organic solvent together with a stabilizing agent being enough for sensing.
Several metal species such as selenite, methylmercury, methylcyclopentadienyl-manganese tricarbonyl, etc. quenched the QD fluorescence following the Stern-Volmer equation. Significant quenching was also observed for non-metal compounds such as hydrogen sulphide. Au NCs stabilized in an aqueous drop with sodium dodecyl sulfate (SDS) and following the same approach as above have proved to be sensitive for the detection of inorganic mercury.
The novel sensing platforms may open the door to on-site trace metal analysis and speciation, with a performance similar or even better in comparison with analytical techniques typically used in central labs.
Acknowledgements: Financial support from the Spanish Ministry of Economy and Competitiveness and the European Commission (FEDER) (Project CTQ2012-32788) is gratefully acknowledged.
Plasmodium falciparum is evolving resistance to Artemisinin Combination Therapy. The gene with the strongest association with resistance is K13. K13 is an ortholog of the well characterized transcriptional regulator Keap1. In this work we transcriptionally characterized a mutant with a transposon inserted in the K13 promoter region which results in dysregulation of K13 at 2 points of the intraerythrocytic cycle of the life-cycle to identify the processes regulated by K13.READ MORE
PfABCk2 gene is ligated into pET21a+ vector with His-tag at C-terminus and transformed into BL-21 (DE3) competent cells that are verified through Miniprep and DNA sequencing. Furthermore, this gene construct is utilized to heterologous express this protein with IPTG and afterwards purified the recombinant protein kinase using nickel affinity chromatography as shown on 10% SDS-PAGE with the expected 36 kDa protein band.READ MORE
Studies have shown that IFI16 acts as an antiviral restriction factor against a number of DNA viruses, by inhibiting viral replication or transcription through epigenetic modifications. However, till date, no specific epigenetic function of IFI16 has been identified. Here, we have discovered that IFI16 recruits two histone methyltransferases on the KSHV episome leading to altered Histone H3K9 methylation, thus regulating its lifecycle.READ MORE