An immunochromatographic strip sensor for sildenafil and its analogues

Abstract

In this study, a new hapten of sildenafil (Sild) was successfully synthesized and a sensitive monoclonal antibody (mAb) against Sild was produced based on this new hapten. The subclass of the mAb was IgG2a, and the half-maximal inhibitory concentration (IC₅₀) of the mAb was 0.53 ng mL⁻¹. Next, an immunochromatographic assay (ICA) was established for detecting Sild and its analogues in functional foods, where the visual detection limit (vLOD) and cut-off values were 0.5 and 20 μg kg⁻¹, respectively. With the aid of a strip scan reader, the ICA can measure Sild with an LOD of 0.7 μg kg⁻¹ and a line range of detection between 1.40 and 13.11 μg kg⁻¹. The whole test process takes only 15 min. Therefore, the ICA provides a useful tool for the on-site detection and rapid initial screening of Sild in functional food samples.