The addition of target viral DNA causes the nanoparticles to form aggregate “clumps,” which leads to a change in their color. Credit: Matthew Mancuso.
Gold nanoparticle conjugates change from bright red to dull purple with the addition of target viral DNA. Credit: Matthew Mancuso.
Cornell scientists have developed a new system that detects viral DNA without relying on expensive equipment, rather combining nanotechnology, microfluidics, and some help from a smartphone. The current iteration of the prototype spots viral DNA of Human herpesvirus 8 responsible for Kaposi’s sarcoma, a tumor often associated with AIDS.
The team will be presenting the system at the Conference on Lasers and Electro Optics in San Jose, California next week.
Some details from the Optical Society:
[G]old nanoparticles are combined (or “conjugated”) with short DNA snippets that bind to Kaposi’s DNA sequences, and a solution with the combined particles is added to a microfluidic chip. In the presence of viral DNA, the particles clump together, which affects the transmission of light through the solution. This causes a color change that can be measured with an optical sensor connected to a smartphone via a micro-USB port. When little or no Kaposi’s virus DNA is present, the nanoparticle solution is a bright red; at higher concentrations, the solution turns a duller purple, providing a quick method to quantify the amount of Kaposi’s DNA.
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