Lateral flow devices such as the one you are more familiar with, the pregnancy test, was developed in the 80s. It contains gold nanoparticles (AuNPs) around 15 nm in size. Its purpose is to detect biomarkers by either competitive or sandwich assays. This discovery paved the way for the development of other diagnostic tools. It is revolutionary in the world of scientific sensors and it has propelled expansion in many areas of research including the biological and imaging, defense and environmental field.
The example above shows the basic principle of how this technology works. A colour change of AuNPs upon aggregation occurs. The inter-particle distances between each particle decreases as it binds to and in the presence of analytes. This aggregation effect of nanoparticles causes plasmon resonance effect and as a result, its optical properties shifts to the red region of the spectrum.
The two papers below are excellent source of information, showing the latest trend on AuNPs as a review paper and the other highlighting some research work for in-vivo drug screening application.
- Saha, K., Agasti, S. S., Kim, C., Li, X. & Rotello, V. M. Gold nanoparticles in chemical and biological sensing. Chem. Rev. 112, 2739–79 (2012).
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Lee, S., Cha, E.-J., Park, K., Lee, S.-Y., Hong, J.-K., Sun, I.-C., … Ahn, C.-H. (2008). A Near-Infrared-Fluorescence Quenched Gold-Nanoparticle Imaging Probe for In Vivo Drug Screening and Protease Activity Determination. Angewandte Chemie, 120(15), 2846–2849.
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