Nanomaterials in Lateral Flow Assay

Point-of-care devices have garnered the interest of scientists in recent years due to their capacity for on-site, bedside, and in-home surveillance in many fields of the medical, biological, pharmaceutical, and food sciences and industries. These devices can be categorized primarily as either portable or stationary. Due to their simple downsizing, mobility, low cost, and low power consumption, portable devices have attracted a great deal of interest. Recently, lateral flow assays have gained popularity as a portable platform due to the simplicity of strip design and the ability to detect with the naked eye. As inseparable components of lateral flow assay, nanomaterials have played a prominent role in enhancing sensitivity due to their large surface area, ease of functionalization, and tunable physical and chemical characteristics based on size, shape, and composition. The conventional lateral flow approach is an immunoassay in which gold nanoparticles with a unique plasmonic surface property show a red color on the test and control lines to enable qualified detection. This approach, with its quantitative limitations and limited sensitivity, is essential for the introduction of novel nanoparticles. Numerous nanoparticles, including quantum dots, carbon nanotubes, magnetic nanoparticles, nanoenzymes, surface-enhanced Raman scattering nanotags, upconversion nanoparticles, and time-resolved fluorescence nanoparticles, have been utilized in the design of lateral flow assays to date. This chapter focuses mostly on the characteristics of various nanoparticles combined with lateral flow assay and associated transduction method for readout of signals produced by nanoparticles, as well as a critical analysis of the resulting approaches.