Nanomaterial Labels in Lateral Flow Immunoassays for Point-of-Care-Testing

Lateral flow immunoassays (LFIAs) have been developed rapidly in recent years and used in a wide range of application at point-of-care-testing (POCT), where small biomolecules can be conveniently examined on a test strip. Compared with other biochemical detection methods such as ELISA (enzyme linked immunosorbent assay) or mass spectrometry method, LFIAs have the advantages of low cost, easy operation and short time-consuming. However, it suffers from low sensitivity since conventional LFIA can only realize qualitative detection based on colorimetric signals. With the increasing demand for more accurate and sensitive determination, novel nanomaterials have been used as labels in LFIAs due to their unique advantages in physical and chemical properties. Colloidal gold, fluorescent nanoparticles, SERS-active nanomaterials, magnetic nanoparticles and carbon nanomaterials are utilized in LFIAs to produce different kinds of signals for quantitative or semi-quantitative detection. This review paper first gives a description of the LFIA principles, and then focuses on the state-of-the-art nanomaterial labelling technology in LFIAs. At last, the conclusion and outlook are given to inspire exploration of more advanced nanomaterials for the development of future LFIAs.