The scientific story began in 2013, before the inception of Big Eye Diagnostics. Back then, Marco Biamonte, now CEO of Big Eye Diagnostics, and Richard Baldwin, then Chief Scientist at nanoComposix, introduced gold nanoshells to the field of lateral flow assays. Gold nanoshells are high-tech nanoparticles, made of a sphere of silica gel, on which a thin layer of gold is deposited. Because of a phenomenon of quantum physics known as “surface plasmon resonance”, these nanoparticles have most unusual optical properties. Despite being made of gold, they look blue, but held against a window, they look reddish, and when deposited on paper, they are black. Because these nanoparticles absorb visible light with extraordinary efficiency, they enhance the sensitivity of lateral flow assays. The first application of the nanoparticles was published in 2017. Over the years, the technology kept being refined over and over, culminating into what is now an ultrasensitive platform for rapid tests. Materials and formulations were optimized so that the tests can withstand demanding conditions. For instance, our river blindness test withstands uninterrupted exposure to 50 °C (122 °F) for six months. This means you can throw it at the back of a truck or a jeep, drive in the most torrid climate, toss it in a warehouse that is not air conditioned for months, and still expect it to work perfectly.
For some applications that require special attention to quality assurance, it may be useful to have a set of negative and positive controls, but those are typically fragile and heat sensitive. Big Eye Diagnostics has developed heat-stable lyophilized positive controls that obviate the need for a cold chain. This can be a major advantage as cold chains can be inordinately complicated and expensive to maintain when shipping to different destinations around the world.
Finally, our sister non-profit company DDTD has developed a smartphone-based application that takes a snapshot of a test, just like you would do it for a check when performing a mobile deposit. The app is lightning fast and within a fraction of a second has taken 10 images, averaged them, analyzed them, and interpreted the test results, and uploaded all the data to a cloud-based repository. GPS coordinates are uploaded by the same token. The main purpose for us is for surveillance of certain infectious diseases and the data can be accessed in real time from anywhere in the world through a web portal. A system of permissions ensures that only people with proper authorization see the data. While we use this for epidemiological purposes, the app can equally be used to provide a user that is not familiar with a certain test step-by-step instructions and final test interpretation.
TEM images of gold nanoshell fabrication. A silica gel sphere (grey, left) is studded with tiny gold crystals (black specs) which are used as nucleation sites to progressively grow a gold nanoshell (black, right). Copyright: nanoComposix.
Comparison of 40 nm gold (left), a commonly used nanoparticle for lateral flow assays, and and gold nanoshells (right). The latter appear darker to the human eye despite being 35 times more diluted.