Prepare to embark on a colorful and illuminating journey.
Before we begin:
Did you know that there is a secret world that exists right in front of your eyes? Did you know that we scientists have tapped into this secret world and are exploiting it to push the boundaries of knowledge?
Do you have a yellow highlighter by you? Hurry! Grab it and follow along! Using the highlighter, draw a box on a sheet of paper. Below is my highlighter box along with one drawn using a sharpie for comparison.
Since we could all use a bit of exercise, take your highlighter drawing and venture out into the sunshine. Do you notice that the box you’ve drawn seems to get even brighter? It almost seems like it is glowing, appearing more yellow than before. So what causes this awesome display of extra brightness? Well, the answer is a phenomenon called fluorescence, and it is the key to the secret world around us.
Fluorescence happens when something absorbs light of a certain energy and then emits light with (typically) less energy.
To better illustrate fluorescence in action, let’s look at our highlighter drawing under black light.
In this setup, the black light provides high energy ultraviolet (UV) light, which is invisible to our eyes. Chemicals in the highlighter ink absorb the UV light and spit it back out as lower energy, visible yellow light. This also happens in sunlight, but the large amount of visible light the sun sends out makes it harder for us to see the fluorescence!
In addition to highlighter, many other common materials fluoresce, including tonic water, cleaning products, antifreeze, some minerals, and even you! (kind of). You are a fluorescent factory in action, as both your blood and urine are fluorescent.
Many professionals exploit fluorescence to enable them to do their jobs more effectively. For example, car crash investigators use antifreeze’s fluorescence to understand accidents. In an exceptionally dirty situation, where automobile fluids are splashed everywhere, a crime scene investigator can pull out a trusty black light and cause antifreeze to fluoresce. Antifreeze stands out amongst the other liquids that do not glow, making it easier to look just at the antifreeze and determine what happened during the crash.
So what does this have to do with sustainable nanotechnology? Similar to the crime scene investigator, we scientists like to use fluorescence to make our lives easier. At the heart of our center’s goals is the idea of making nanotechnology safer and more sustainable. To do that, we first need to understand how current nanomaterials interact with simple organisms and cells (see Jared’s post from last week to see one such organism). Often this involves putting an organism or cell in contact with nanomaterials and attempting to watch where these tiny materials go. This is not an easy task, but thankfully we can utilize fluorescence to aid us in our endeavors. There are many nanomaterials that fluoresce, including titanium dioxide, diamond, and gold nanoparticles, along with one of our favorite types of nanoparticles, known as quantum dots.
Once we add quantum dots to an organism, they become almost impossible to see under normal light. However, with the help of microscopes and different light sources we can cause our quantums dots to fluoresce and be seen. Just like the accident investigator, we make the quantum dots stand out against the background of other parts of the organism in order to see where they went and maybe even how they got there. Just like we can use fluorescence to track nanoparticles inside organisms, scientists already use techniques like this to look at different components of cells.
So, now that you understand a little about this hidden world of fluorescence, you may ask how you can use fluorescence to bring a little cheer into your own life. Say for instance, you are a scientist who works a little too often (e.g., ME) and therefore can really use brownie points with your fiancé around Valentine’s Day (again purely hypothetical). I’ve got your solution! Fluorescent flowers!
Open up a highlighter, pull out the ink cartridge, and squeeze a few drops into some water. Place some flowers into the very yellow solution and wait a day for the flowers to take up the fluorescent dye (this can be difficult for those with short attention spans). You will now have a beautiful glowing bouquet to present to your sweetheart.
At the end of the day, fluorescence is a pretty big deal. It is all around us, makes peoples’ jobs easier, enables scientists to answer incredibly complex questions, and generally lights up many festive occasions. Without fluorescence the world would be a far duller place and much more difficult to comprehend. That’s all for now. Stay tuned for my upcoming post: How Small is Small?-A Nano Perspective.
References & Further Reading:
Eastern Indiana Police Track Antifreeze to Car in Crash