You don’t feel well and so you go to the doctor. To diagnose what is wrong with you, a doctor can do tests from the outside by looking in your ears and down your throat. But sometimes that’s not enough because there’s a limit to what the doctor can see from the outside and getting inside is painful.
One way to see inside is to use X-rays. This diagnostic tool was invented back in 1895 and while X-rays are great for seeing dense things like bones, they don’t do a great job looking at softer things like your brain. For that there are MRI (magnetic resonance imaging) andCT (computed tomography) machines, which provide images showing differences between healthy and sick cells that a doctor may want to take a closer look at. While some kinds of cancer are easy to spot with MRI or CT results, others are really too small to show up on the images.
What doctors need is something to make the cells they want to see appear different from the rest of the cells. Scientists are using nanotechnology to create different kinds of nanomaterials that will help doctors see inside the body in more detail.
How Can Nanoparticles Help?
Your body was designed to keep things on the outside out and keep most of the stuff on the inside in. The various cells that make up your skin, the lining of your intestinal tract and other places in your body forma tight protective barrier. To get past these barriers devices need to be very small. Nanoparticles are very, very small—around 100 manometers wide, or about1/1000 the width of a hair—so they could do the job because they can make their way in and around cells.
Scientists today are making lots of different kinds of nanoparticles. The newest work is focused on theranostic particles, which can be used to both diagnose and treat, hence the name theranostics =therapy+diagnostics. These theranostic nanoparticles are designed to be smart so they can be targeted to a specific disease. To fight cancer, theranostics could carry antibodies that would home in on cancer cells. Once on site these nanoparticles would release a payload of medicine right at the site of the disease. Some theranostics are made to be sensitive to microwaves so that they heat up and release their payloads, while others are triggered by light. They can also be made from metals like iron that can be seen using MRI. With nanotechnology some day doctors will have a whole new set of tools to treat disease that will be more effective and work in ways we can only imagine.
Another promising nanomaterial is quantum dots. Quantum dots are sometimes called artificial atoms and are made of chemicals like cadmium and selenium.These tiny particles are only a few nanometers in size. They are so small that they contain only a thousand or so atoms.
Quantum dots are fluorophores, which means that they can absorb light at one wavelength and emit light at another wavelength. Some quantum dots absorb and emit light with long wavelengths in the infrared spectrum. What makes quantum dots potentially useful for imaging the body is that infrared light can penetrate deeper into the body than visible light. So if quantum dots can be directed to cancer cells, doctors could image tumors deep inside the body.
To do this, scientists would attach special molecules to quantum dots that would find and stick only to cancer cells. Antibodies are one kind of special molecule used to target and bind to cancer cells. When the antibodies find their target, the quantum dots attached to them could be tracked by their fluorescence, providing a deeper look inside the body than what is currently available today.