Aptamer-linked immobilized sorbent assay for detection of VP1 of foot and mouth disease virus serotype O

Foot and Mouth Disease (FMD) is one of the most devastating animal diseases. Infected animals, such as swine, develop vesicles, often leading to morbidity or depopulation of exposed herds. Current FMD diagnosis relies on serologic and immuno-based methods, which commonly encounter cross-reactivity and cost issues. Therefore, a simple and portable diagnostic tool would greatly aid its detection efforts. This study generated a novel aptamer sequence targeting viral protein 1 (VP1) of serotype O FMD virus (FMDV) by Systematic Evolution of Ligands by Exponential Enrichment (SELEX). The generated FMDV VP1-specific aptamer sequence was characterized and incorporated into an Aptamer-linked Immobilized Sorbent Assay (ALISA)-based microplate platform to detect FMDV VP1. Results showed that the aptamer, FMDV Apt, had an estimated dissociation constant (Kd) of 14 ± 8.6 nM, showing strong affinity for VP1 of FMDV. A concentration-dependent linear relationship (R2 = 0.9354) within a concentration range of 0.50 ng/mL – 5.0 ng/mL of FMDV VP1 protein was observed. The limit of detection (LOD) was determined to be 1.3 ng/mL, and the limit of quantification (LOQ) was approximately 4 ng/mL. Moreover, the FMD ALISA did not exhibit cross-reactivity when tested with high concentrations (500 ng/mL – 2,000 ng/mL) of non-targets, indicating its robustness and potential application in other detection platforms. The newly developed screening tool would facilitate efficient and inexpensive monitoring of potential biohazard risks posed by FMDV.