Chimeric DNA/LNA-based biosensor for the rapid detection of African swine fever virus

Publication date: 1 July 2018
Source:Talanta, Volume 184
Author(s): Massimo Biagetti, Massimiliano Cuccioloni, Laura Bonfili, Valentina Cecarini, Carla Sebastiani, Ludovica Curcio, Monica Giammarioli, Gian Mario De Mia, Anna Maria Eleuteri, Mauro Angeletti
African swine fever (ASF) virus is a DNA virus responsible for a severe haemorrhagic fever in pigs, which (still in the absence of vaccination strategies) results in high mortality rates. Herein, we present a biosensor-based method for the detection of ASF viral DNA in the blood of pigs. The biosensor exploits a single-strand DNA probe with locked nucleic acid nucleotides (LNA) substitutions as the complementary recognition element for the conserved region of vp72 gene of ASF virus.The biosensor was calibrated using qPCR-quantified ASF viral DNA extracted from the blood of pigs experimentally infected with the virulent Italian isolate 49/08, genotype I. Globally, the proposed biosensor showed good sensitivity and specificity, with the limits of detection (LOD) and quantification (LOQ) being 178 and 245 copies/μL of genomic ASF viral DNA, respectively. The reversible nature of the interaction between the DNA/LNA probe and the target DNA sequence granted multiple rapid analyses, with up to 40 analyses per single surface possible, and a single test requiring approximately 5 min.When applied to non-amplified DNA extracts from the blood of field-infected pigs, the assay discriminated between ASFV-infected and ASFV non-infected animals, and allowed the rapid quantification of ASF viral DNA, with values falling in the range 373–1058 copies/μL of genomic ASFV DNA. In this range, excellent correlation was observed between the results of this biosensor and OIE-approved qPCR.This method represents a promising screening assay for preliminary ASF diagnosis, having the major advantages in the relative rapidity, ease-of-use, the reusability of the sensing surface, and low cost per single test.

Graphical abstract

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