Detection of nucleic acids and elimination of carryover contamination by using loop-mediated isothermal amplification and antarctic thermal sensitive uracil-DNA-glycosylase in a lateral flow biosensor: application to the detection of Streptococcus pneumoniae

Abstract

The authors report on a loop-mediated isothermal amplification (LAMP) scheme that uses antarctic thermally sensitive uracil-DNA-glycosylase (AUDG) for simultaneous detection of nucleic acids and elimination of carryover contamination. It was applied in a lateral flow assay (LFA) format. The assay has attractive features in that it does not require the use of labeled primers or probes, and can eliminate false-positive results generated by unwanted hybridization between two labeled primers or between a labeled primer and probe. LAMP amplification and AUDG digestion are conducted in a single pot, and the application of a closed-tube reaction prevents false-positives due to carryover contamination. The method was applied to the detection of the human pathogen Streptococcus pneumoniaein in pure cultures and spiked blood samples. This LFA can detect S. pneumoniae in pure cultures with a 25 fg.μL^-1 detection limit and in spiked blood samples with a 470 cfu.mL^-1 detection limit. Conceivably, this assay can be applied to the detection of various other targets if the specific LAMP primers are available. Graphical abstract ᅟ.

Keywords: Diagnostic technique; False-positive result; Limit of detection; Nanoparticles; Nucleic acid amplification.