[Pedestrian]

Originally Posted by homebucket

Might be a dumb question but since you’re a physicist by trade, is it even theoretically possible to implant a chip into someone via a vehicle like a clear, colorless solution injected intramuscularly? I know things like valves and sensors can be implanted through major arteries and veins but you can actually see those with your naked eye.

Amazing things are being done with nanoparticles, perhaps more with organic ones than with inorganic. For example:

When atherosclerosis occurs in coronary arteries, blockages due to plaque or calcification-induced ruptures can lead to a clot, cutting blood flow to the heart, which is the cause of most heart attacks. When the condition occurs in the vessels leading to the brain, it can cause a stroke.

"An artery doesn't need to be 80 percent blocked to be dangerous. An artery with 45% blockage by plaques could be more rupture-prone," Chung said. "Just because it's a big plaque doesn't necessarily mean it's an unstable plaque."

Chung said that when small calcium deposits, called microcalcifications, form within arterial plaques, the plaque can become rupture prone.

However, identifying whether blood vessel calcification is unstable and likely to rupture is particularly difficult using traditional CT and MRI scanning methods, or angiography, which has other risks.

"Angiography requires the use of catheters that are invasive and have inherent risks of tissue damage," said Chin, the lead author. "CT scans on the other hand, involve ionizing radiation which can cause other detrimental effects to tissue."

Chung said that the resolution limitations of traditional imaging offers doctors a "bird's eye view" of larger-sized calcification, which may not necessarily be dangerous. "If the calcification is on the micro scale, it can be harder to pick out," she said.

The research team developed a nanoparticle, known as a micelle, which attaches itself and lights up calcification to make it easier for smaller blockages that are prone to rupture to be seen during imaging.

Chin said the micelles are able to specifically target hydroxyapatite, a unique form of calcium present in arteries and atherosclerotic plaques.

https://www.sciencedaily.com/release...1209161147.htm

or

Michigan State University and Stanford University scientists have invented a nanoparticle that eats away -- from the inside out -- portions of plaques that cause heart attacks.

Bryan Smith, associate professor of biomedical engineering at MSU, and a team of scientists created a "Trojan Horse" nanoparticle that can be directed to eat debris, reducing and stabilizing plaque. The discovery could be a potential treatment for atherosclerosis, a leading cause of death in the United States.

The results, published in the current issue of Nature Nanotechnology, showcases the nanoparticle that homes in on atherosclerotic plaque due to its high selectivity to a particular immune cell type -- monocytes and macrophages. Once inside the macrophages in those plaques, it delivers a drug agent that stimulates the cell to engulf and eat cellular debris. Basically, it removes the diseased/dead cells in the plaque core. By reinvigorating the macrophages, plaque size is reduced and stabilized.

Smith said that future clinical trials on the nanoparticle are expected to reduce the risk of most types of heart attacks, with minimal side effects due to the unprecedented selectivity of the nanodrug.

https://www.sciencedaily.com/release...0128114720.htm

There are actually quite a few experimental uses of nanoparticles in biomedicine now.

By definition, a nanoparticle is any particle less than 100 nanometers in size. I'm pretty sure no one could see that. It might make the fluid it's in appear cloudy if the concentration is high enough.

But I'm wondering why you ask. What use are you thinking of in relation to COVID?