A lateral flow assay for the determination of human tetanus antibody in whole blood by using gold nanoparticle labeled tetanus antigen

The authors describe a lateral flow assay (LFA) for the antibody against the infectious bacterium Clostridium tetani. Gold nanoparticles (AuNPs) were linked to tetanus antigen and are captured in the test line via the formation of a sandwich structure composed of AuNP-labeled tetanus antigen, tetanus antibody, and tetanus antigen. This leads to the formation of a characteristic red line due to the accumulation of AuNPs. The formation of the color line allows for a highly sensitive and selective detection of tetanus antibody, both with bare eyes and by smartphone-based quantitative analysis. This assay offers a wide detection range from 0 to 0.5 IU·mL⁻¹ and has a linear relationship from 0.01 to 0.1 IU·mL⁻¹ with an experimental detection limit of 0.01 IU·mL⁻¹. This assay is simple, fast, inexpensive and highly selective. When applied to the detection of tetanus antibody in spiked whole blood, it provided reliable results that compared well to those obtained with a commercial ELISA kit. .