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The development of a gold nanoparticle aptamer assay is persued for rapid and sensitive determination of histamine in foodstuffs, which could be deployed for on-site use. The assay is based on a histamine-specific aptamer and gold nanoparticles and the salt-induced aggregation of the particles in the presence of histamine indicated by the color change from red to blue. Gold nanoparticle size, salt type, and concentration as well as aptamer concentration were optimized, and using optimum conditions, a limit of detection of 8 nM (~ 0.05 mg/kg) was obtained. Finally, the aptamer AuNP assay was applied to the determination of histamine in quality control fish samples. The histamine levels of these samples had previously been determined using HPLC and commercial ELISA kits by numerous independent laboratories and a good correlation was obtained. The developed AuNP assay is rapid, sensitive, and reproducible. [ABSTRACT FROM AUTHOR]

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 × 10−11 M (190 amol), equivalent to 8.67 × 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 °C. 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. [ABSTRACT FROM AUTHOR]