A smartphone-based enhanced colorimetric immunoassay for the detection of Trichinella spiralis infection

Trichinellosis is a serious foodborne and zoonotic parasitic disease caused by Trichinella family. At present, the main on-site detection method for Trichinella spiralis (T. spiralis) infection is the lateral flow assay (LFA). Other diagnostic techniques for this parasite cannot be applied to on-site testing due to their reliance on special instruments. Here, we established an ELISA smartphone-based method for detecting anti-T. spiralis antibodies in pig serum. The use of horseradish peroxidase-labeled goat anti-pig IgG-modified gold nanoparticle (AuNPs@HRP-IgG) effectively increased the sensitivity of the method. The entire reaction was carried out at room temperature without the need for special instruments. A low-cost and portable device for imaging and processing experimental data was also developed. Validation analysis revealed that the specificity of the test was 98.89%, while its sensitivity was 100.00%. T. spiralis antibodies could be detected in pig serum beginning at 25 dpi after infection with the muscle larvae. This visual immunosensor facilitates on-site detection of T. spiralis, especially in regions lacking specialized laboratory equipment.