Luminescent Materials as Diagnostic Reporters in Lateral Flow Assays

The need for rapid and reliable point-of-care (POC) diagnostic testing has led to extensive research in developing new assays and associated reporter technologies. One of the most commonly used POC diagnostics is the lateral flow assay (LFA), most well-known for the home pregnancy test because of its simplicity, speed, low cost, and portability. The reporter particles in the LFA play a crucial role in performing the diagnostic readout and dictating the test’s sensitivity. Gold nanoparticles are often employed as the LFA reporters in commercial tests due to their low cost, ease of functionalization, and visualization by the human eye; however, their sensitivity is limited. Alternatively, work on luminescence-based reporter technologies has yielded improved LFA performance. These efforts have focused primarily on photoluminescent reporters, including organic fluorophores, quantum dots, lanthanide chelates, persistent luminescent phosphors, and upconversion phosphors. Chemiluminescent reporter techniques have also been investigated. In most cases, these optical reporters show enhanced sensitivity compared to conventional gold nanoparticle-based assays.

Here, the mechanisms, advantages, and disadvantages of these different luminescent reporters and their potential benefits in LFAs are examined. Persistent luminescent phosphor reporters and chemiluminescent reporters are applied in various LFAs for antigen detection, antibody detection, and nucleic acid (DNA) detection. This research demonstrates that luminescence-based LFAs can reach lower limits of detection than LFAs with traditional reporters, but they can also be capable of quantitative and multiplex analyte detection. The resulting next-generation LFA can obtain more reliable and precise results while simultaneously having lower assay running time and being more cost-effective. As a result, the luminescent reporters make LFAs well-suited for POC medical diagnostics and sets the stage to use LFAs in other fields such as the food and agricultural industry and environmental testing.