Canine parvovirus 2 detection with a gold nanoparticles protocol.

Canine parvovirosis, caused by canine parvovirus 2 (CPV-2), affects mostly young unvaccinated dogs, causing a severe gastrointestinal condition that can lead to death. The development of low-cost and rapid diagnostic techniques is necessary, since only clinical diagnosis is not conclusive. Biosensors, such as gold nanoparticles, have dynamic physicochemical characteristics that allow the transduction of various signals (optical, plasmonic, electrochemical), which makes them efficient sensors. The objective of the present project was to develop and standardize the identification of CPV-2 from stool samples using gold nanoparticles modified with antibody deposition. Protocol was standardized using monoclonal antibody, polyclonal antibody, and combination of both. A total of 60 stool samples positive and 5 negatives in qPCR for CPV-2 were submitted to the technique after dilution at a ratio of 1:150 in PBS. For all antibodies there was a significant increase in wavelength by the LSPR technique after the addition of the positive samples. The combination of both antibodies showed the greatest difference. In contrast, when adding the negative samples, there was no statistically significant difference in wavelength compared to the step with the antibodies. Samples of adenovirus and porcine circovirus 2 were also submitted to the technique, and no nonspecific binding was detected. When comparing the wavelength increase values, with the qPCR and hemagglutination results, no correlation of values was found, evidencing that this protocol presents qualitative results (positive and negative). In conclusion, the detection of CPV-2 was confirmed by LSPR analysis, and this is a technique that provides a sensitive and specific diagnosis quickly (40 min) and at low cost (~R$5/sample). The results found here are promising and may serve as a basis for future point of care testing protocols. (AU)