Lateral-flow technology: From visual to instrumental

• Lateral-flow tests first launched commercially in 1984.
• Trends are driving lateral-flow technology towards ready transmission of data.
• We chart the inevitable evolution of the visually-read lateral-flow strip to more advanced instrumented and printed electronic versions.
• We examine labelling strategies, recognition elements the relative merits of optical and electrochemical transducers.

Lateral-flow tests were first launched commercially in 1984, as a simple urine-based pregnancy test for home use. The simplicity of the visual readout delivered by the basic lateral-flow format proved to be a very popular. However, the recent apparently unstoppable trend towards portable and wearable technology is driving the lateral-flow strip towards an industrial interface that will enable it to interface with big data and expert systems, and where ready transmission of data is essential. In this review, we chart the inevitable evolution of the visually-read lateral-flow strip to more advanced instrumented versions and consider the future of this very flexible approach to delivering simple affinity assays. We examine recent labelling strategies, the relative merits of optical and electrochemical transducers and explore the evolution of recognition elements that are now being incorporated into these systems.