There's an animated show, The Magic School Bus, where a science teacher takes her students on magical adventures to impossible locations. Sometimes they head to outer space, or they might travel back in time, but many times, they shrink down to microscopic size and go touring inside of a human body.
Science hasn't quite caught up to Ms. Frizzle's amazing field trips, but we're getting closer! We can perform microsurgery on blood vessels, where the surgeon looks through a microscope as they operate on fragile veins and arteries. We can put a tiny camera inside a pill so that when the patient swallows it, we can capture images of their stomach and intestines. That one sounds so much like an episode of The Magic School Bus, I feel like they should paint the pill school-bus yellow!
Now scientists want to pursue nanomedicine, where the instruments and components are too small for even a standard light microscope to see! By going that small, doctors could target certain cells, like cancer, for treatment. They could deliver medicine more effectively to the inside of the eye, which usually resists treatments. And they could make tests and imaging more effective so doctors could get a better view of problem areas.
One problem in creating devices for nanomedicine is that the smallest standard motor we can build is about 0.1 mm. The gears of a motor that work like one in a car just don't work at a smaller size. That means scientists and engineers have to get creative.
For example, a group of Swedish scientists built a set of turning gears that could fit within the width of a human hair! These gears are made of silica that reacts to light. The gears begin to turn in one direction when exposed to normal light. If the light is polarized, the gears turn in the opposite direction. The stronger the light intensity, the faster the gears turn. If we can get light inside the right part of the human body, these little gears could "drive" devices to deliver medicine.
Scientists recently had a breakthrough with a "motor" that is even smaller. This doesn't look like a regular motor at all, and it's only 16 atoms across! Engineers made a tiny platform of gallium and palladium atoms, then placed a molecule of acetylene on top. The acetylene molecule rotates when electricity is applied. This could provide movement for devices inside the body, but there's a catch. The atoms have to be cooled to almost absolute zero, so it isn't quite ready for use inside humans yet.
Another super creative approach to nanomedicine is using DNA as a building material. Scientists call this technique "DNA origami." Scientists are testing DNA structures with special molecules attached to them. The "DNA robots" don't have a motor, but they move along in the bloodstream, hiding their special molecules until they come in contact with a very acidic environment - which is common in cells that have cancer! These promising robots then unleash their hidden molecule, which destroys the cancer cells.
Medicine isn't the only area getting smaller! The sizes of transistors keep shrinking, too. These little parts can amplify or switch off electrical signals, which allow computer chips and smart phones to run. Take a look at how transistor size has changed since the year 1997:
If I brought this graph into the classroom, here are some questions I'd have to go with it:
💡What is the change in transistor size from 1997 to 2000?
💡In 2022, scientists built a transistor that was 0.34nm in size. Could this graph be used to show that data?
💡In technology, there is an idea called "Moore's Law." This states that the size of a transistor can be cut in half every two years. Does this pattern show up on the graph? Use specific data to justify your statement.