Sample-to-answer Aggregation-Induced Emission Lateral Flow Immunoassay (ALFIA) for rapid and sensitive on-site detection of Toxoplasma gondii antibodies across multiple host species

Toxoplasma gondii (T. gondii) is an apicomplexan parasite capable of infecting any nucleated cell in humans and warm-blooded animals. Unfortunately, there is currently no effective treatment or vaccine available for T. gondii infection. Consequently, early detection, particularly methods that support rapid on-site testing across multiple host species, becomes crucial for controlling and preventing T. gondii infection. To address this issue, based on the double antigen sandwich principle, we developed the Aggregation-Induced Emission (AIE) Lateral Flow ImmunoAssay (ALFIA) for detecting T. gondii antibodies. ALFIA employs T. gondii antigen for both capturing and detecting T. gondii antibodies, eliminating the need for secondary antibodies of specific species and enabling cross-species detection of T. gondii antibodies. Compared to commonly used colloidal gold test strips, the proposed ALFIA demonstrated a 16-fold improvement in sensitivity when visually inspected and a 32-fold enhancement when using a commercial test strip reader. Furthermore, clinical verifications showed that ALFIA reached 100 % accuracy in detecting porcine and feline sera, with no discrepancies compared to commercial ELISA kits. ALFIA offers the capability of achieving sample-to-answer detection in 10 min. It is anticipated that ALFIA will serve as an effective clinical solution for rapid on-site detection of T. gondii antibodies across various host species.