To understand what's described in this article, it helps to start by understanding how a lateral flow test works: [0]. Basically, the active ingredient in a lateral flow test consists of two components chemically bonded together: a colored material and a chemical that bonds to the thing we're testing for, called the "conjugate".
If the desired material is present in the flowing liquid, the conjugate bonds to the test material, and the entire particle is carried along in the flow of liquid. Then, we look for the presence of the colored material downstream. If the color shows up, the test is positive, if not the test is negative.
The problem that this paper is trying to solve is that previously used colored materials (e.g. tiny particles of gold) can't be detected in very small amounts because the color blends in with the background noise, if there's only a very small amount of it.
These new particles consist of a tiny diamond with a carefully designed irregularity in the crystal structure, where a carbon atom in the diamond is replaced by a nitrogen atom. These diamonds don't just emit a single color of light. Instead, they can emit different colors of light if you shine the right type/amount of microwaves on the diamonds.
As a result, these diamonds don't blend in with the background noise, even at very small amounts, because the background doesn't change color as you shine different microwaves on it.
They were able to detect a concentration of these diamond particles 100,000 times less strong than the prior gold particles. As a result, a test made with these particles can return a positive test result with much smaller amounts of the material being detected in the initial sample.
As an example, the researchers were able to make a test that could detect the presence or absence of single HIV RNA molecule. This test combined a 10 minute chemical treatment step (amplification), followed by a lateral flow test based on these diamond particles and a (previously known) conjugate for the HIV RNA molecule.
The research article call them "fluorescent nanodiamonds", fluorescence is a quantum effect, so the press article an mix that and get "quantum nanodiamonds" that is more linkbaity.
Nitrogen Vacancy is a well known technique (but is far away from my area). If you change a Carbon in the diamond by a Nitrogen, then the Nitrogen will pick an unpaired electron and you can mess with this poor electron with it https://en.wikipedia.org/wiki/Nitrogen-vacancy_center
By what mechanism does a nanoparticle detect the presence of a virus?
The article mentions the nanoparticle emitting a kind of signal via "nitrogen vacancy" defects in the diamond structure to signal the presence of a target virus, but glosses how the thing is detected. Are these nanoparticles somehow imprinted with a target signature or something?
>The most important applications and properties of nanodiammonds in infection management are presented in Figure 2. NDs harbor a nitrogen-vacancy enabling them to emit fluorescence when illuminated [9,45,46]
Basically you design your nano diamonds to bind to a virus, antibody or bacteria and then using imaging you can identify the presence of them in your sample.
I don't understand how you ensure your sample is "clean" as in doesn't have non-bound NDs I'm not sure but that's the gist of it from what i gather.
If the desired material is present in the flowing liquid, the conjugate bonds to the test material, and the entire particle is carried along in the flow of liquid. Then, we look for the presence of the colored material downstream. If the color shows up, the test is positive, if not the test is negative.
The problem that this paper is trying to solve is that previously used colored materials (e.g. tiny particles of gold) can't be detected in very small amounts because the color blends in with the background noise, if there's only a very small amount of it.
These new particles consist of a tiny diamond with a carefully designed irregularity in the crystal structure, where a carbon atom in the diamond is replaced by a nitrogen atom. These diamonds don't just emit a single color of light. Instead, they can emit different colors of light if you shine the right type/amount of microwaves on the diamonds.
As a result, these diamonds don't blend in with the background noise, even at very small amounts, because the background doesn't change color as you shine different microwaves on it.
They were able to detect a concentration of these diamond particles 100,000 times less strong than the prior gold particles. As a result, a test made with these particles can return a positive test result with much smaller amounts of the material being detected in the initial sample.
As an example, the researchers were able to make a test that could detect the presence or absence of single HIV RNA molecule. This test combined a 10 minute chemical treatment step (amplification), followed by a lateral flow test based on these diamond particles and a (previously known) conjugate for the HIV RNA molecule.
[0]: https://en.wikipedia.org/wiki/Lateral_flow_test
Nitrogen Vacancy is a well known technique (but is far away from my area). If you change a Carbon in the diamond by a Nitrogen, then the Nitrogen will pick an unpaired electron and you can mess with this poor electron with it https://en.wikipedia.org/wiki/Nitrogen-vacancy_center
The article mentions the nanoparticle emitting a kind of signal via "nitrogen vacancy" defects in the diamond structure to signal the presence of a target virus, but glosses how the thing is detected. Are these nanoparticles somehow imprinted with a target signature or something?
>The most important applications and properties of nanodiammonds in infection management are presented in Figure 2. NDs harbor a nitrogen-vacancy enabling them to emit fluorescence when illuminated [9,45,46]
Basically you design your nano diamonds to bind to a virus, antibody or bacteria and then using imaging you can identify the presence of them in your sample.
I don't understand how you ensure your sample is "clean" as in doesn't have non-bound NDs I'm not sure but that's the gist of it from what i gather.