Ultrasensitive, rapid and inexpensive detection of DNA using paper based lateral flow assay

Sensitive, specific, rapid, inexpensive and easy-to-use nucleic acid tests for use at the point-of-need are critical for the emerging field of personalised medicine for which companion diagnostics are essential, as well as for application in low resource settings. Here we report on the development of a point-of-care nucleic acid lateral flow test for the direct detection of isothermally amplified DNA. The recombinase polymerase amplification method is modified slightly to use tailed primers, resulting in an amplicon with a duplex flanked by two single stranded DNA tails. This tailed amplicon facilitates detection via hybridisation to a surface immobilised oligonucleotide capture probe and a gold nanoparticle labelled reporter probe. A detection limit of 1 7 10−11 M (190 amol), equivalent to 8.67 7 105 copies of DNA was achieved, with the entire assay, both amplification and detection, being completed in less than 15 minutes at a constant temperature of 37 \ub0C. The use of the tailed primers obviates the need for hapten labelling and consequent use of capture and reporter antibodies, whilst also avoiding the need for any post-amplification processing for the generation of single stranded DNA, thus presenting an assay that can facilely find application at the point of need

The separation-preconcentration and determination of ultra-trace gold in water and solid samples by dispersive liquid-liquid microextraction using 4-ethyl-1(2-(4-(4-nitrophenyl)piperazin-1-yl)acetyl)thiosemicarbazide) as chelating agent and flame atomic absorption spectrometry

Soylak, Mustafa/0000-0002-1017-0244WOS: 000431928200014A selective separation and preconcentration method for the determination of gold ions in water and ore samples has been developed using dispersive liquid-liquid microextraction, followed by flame atomic absorption spectrometry. 4-Ethyl-1(2-(4-(4-nitrophenyl)piperazin-1-yl)acetyl)thiosemicarbazide) (NPPTSC) has been used for the first time as new chelating reagent. A mixture of ethanol (dispersive solvent) and carbon tetrachloride (extraction solvent) was used. Some parameters affecting the extraction procedure including the type and volume of the extracting and dispersive solvents, HNO3 concentration, the chelating agent amount, volume of sample, and foreign ions have optimized. Also, the complex formation between gold ions and the ligand has been investigated in a methanol-water solution (1:1) using UV-visible spectrometry. The spectrophotometric titration data showed that of Au-NPPTSC complex composition was found to be 3:2. After optimizing the instrumental and experimental parameters, we achieved a detection limit of 1.5 mu g L-1, a preconcentration factor of 50, and a linear dynamic range of 10.0-400.0 mu g L-1. The relative standard deviation obtained 2.1% at 50 mu g L-1 for gold ions (n = 10). The proposed method was successfully performed for the determination of gold in certified reference material, environmental water, and ore samples.Scientific Research Projects of Giresun University [101016-131]The financial support of the unit of the Scientific Research Projects of Giresun University (Project No.: 101016-131) (Giresun Turkey) is gratefully acknowledged and also gratitude to Karadeniz Technical University (Trabzon, Turkey) for laboratory facilities