Self-propelled Janus nanomotor as active probe for detection of pepsinogen by lateral flow immunoassay

The feasibility of using nanomotors as active probes for lateral flow immunoassay (LFIA) is demonstrated. We synthesized Au@mSiO₂@Pt Janus nanomotor, where nanolayer of Pt was deposited on the half side surface of the Au@mSiO₂ nanoparticles, which can catalyze the decomposition of H₂O₂ to produce driving force for the nanomotor. Subsequently, the motion characteristics of the Au@mSiO₂@Pt nanomotor in static fluidic environment and dynamic flow field was studied to pave the way for its practical application in lateral flow immunoassay (LFIA). At last, the Au@mSiO₂@Pt nanomotor was modified with antibody and then used as active immunoassay probe in LFIA. We chose gastric function index, pepsinogen II (PG II) and pepsinogen II (PG II), as the target analytes. The results indicated that, compared with traditional Au nanoprobe, the nanomotor-based probe can significantly improve the sensitivity by increasing the probability and efficiency of antigen and antibody binding. A limit of detection (LOD) of 2.2 ng/mL for PGI, and 2.1 ng/mL for PG II was achieved. This work provides a new solution for enhancing the capability of immune detection, and we believe the nanomotor-based LFIA will have great potential in high-sensitivity point-of-care-testing in the future.