ELISA-on-a-chip for on-site, rapid determination of anti-rabies virus antibodies in canine serum

Massive pet vaccination has been needed in most countries to control rabies virus dissemination, and the antibody produced in the body must be monitored. To this end, standard analytical methods involving cell cultures infected with the virus were established; however, this analytical approach requires several days under laboratory conditions. To facilitate antibody testing in the field, we developed a rapid immunosensor that can conduct the enzyme-linked immunosorbant assay (ELISA) on a membrane strip-contained chip (ELISA-on-a-chip; EOC) based on a chromatographic approach. The ERA strain virus particles were used as the capture ligand and immobilized on a predetermined site of the membrane. The assay was performed through the sequential addition of the sample and detection antibody labeled with an enzyme. This allowed us to minimize side effects due to the presence of normal antibodies in the serum sample. Total analysis required approximately 20 min until the final colorimetric signal was generated. The analytical results for 40 canine serum samples, 20 positives and 20 negatives, were highly consistent with those obtained using a reference system, i.e., (Platelia™ Rabies II test kit), approved by the World Organization for Animal Health.