Selection of Aptamer Against Ecytonucleospora hepatopenaei and Its Utilization in Lateral Flow Biosensor for Detection

Ecytonucleospora hepatopenaei (EHP) is an obligate intracellular microsporidian that primarily infects the epithelial cells of the shrimp digestive systems and is a major pathogen plaguing the shrimp industry. The development of a robust detection system is crucial for facilitating point-of-care, affordable, and equipment-free identification of this pathogen, especially in field places. This present study involved screening aptamers for EHP spores through the whole-cell Systematic Evolution of Ligands by Exponential Enrichment (SELEX) technique, resulting in the identification of the most suitable aptamer (Apt-6) with a dissociation constant (K_d) of 8.28 nM. By utilizing this aptamer alongside the hybridization chain reaction (HCR), we have established a visual detection method for EHP, employing lateral flow strips. This method exhibits high specificity, effectively differentiating EHP from similar microsporidian and common shrimp pathogens with a detection limit of EHP of 7.8 × 10² spores/mL. The method eliminates the need for genomic DNA extraction, which saves detection time and decreases the possibility of contamination. This is the inaugural screening of the aptamer against the EHP, and it is anticipated that the specific aptamer and the convenient assay will offer an additional option for EHP detection, particularly in field settings.