Lateral flow assays for rapid detection of drugs of abuse: A review focusing on nanomaterial labels and intelligent analysis.

Drug abuse poses a severe threat to public health and societal security, necessitating the development of simple, fast, portable, and highly sensitive detection methods. Lateral flow assays (LFAs) have drawn considerable attention due to their ease of use, cost-effectiveness, and rapid results, making them suitable for point-of-care testing. This review summarizes recent advances in LFAs for detecting drugs of abuse in different matrices since 2017, covering (1) the evolution, configuration, and principles of LFA technology and sample preparation for LFAs; (2) recognition elements (e.g., antibodies and aptamers); (3) diverse nanomaterial labels, including colorimetric (e.g., gold nanoparticles and carbon nanotubes), luminescent (e.g., quantum dots, up-conversion nanoparticles, time-resolved fluorescence microspheres, and afterglow luminescent materials), magnetic, surface-enhanced Raman scattering, electrochemical, and multi-modal detection materials; and (4) intelligent analysis based on smartphone technology and artificial intelligence, along with an outlook on future development directions. This review is expected to provide useful insights for the future development and application of on-site LFAs in detecting illicit drugs and related small molecules.