Strip modification and alternative architectures for signal amplification in nanoparticle-based lateral flow assays

Nanoparticle (NP)-based lateral flow assay (LFA) technology has outstanding characteristics that make it ideal for point-of-care bioanalytical applications. However, LFAs still have important limitations, especially related to sensitivity, which is in general worse than that of other well-established bioassays such as ELISA or PCR. Many efforts have been made for enhancing the sensitivity of LFAs, mainly actuating on the nanoparticle labels and on alternative optical detection modes. However, strip pads modification for such a purpose is an incipient vast field of research. This article gives a brief overview on the recent advances proposed for signal amplification actuating on different pads and the general architecture of the LFA strips. Such strategies offer universal tools that can be adapted to any LFA, independently of the kind of sample, analyte, and label. The principles of the different strategies developed to achieve novel signal amplification and sensitive detection are discussed, and some examples of relevant approaches are highlighted, together with future prospects and challenges.