I grew up in a small city in the north of Iran, next to the Caspian Sea. My father is an agricultural engineer, a country boy who values academic achievements. He's my favorite person in the family, who is full of passion for life and always has a question to ask, always.
No matter how old you are, how educated you are, how interested you are, he always has a question to challenge you. A question that is simple, but somehow difficult to answer. When I was eight, he asked me, why is there a time difference between countries? I answered, very proudly, of course, because the earth is spinning, Papa. it means that it takes seven hours for Canada to be in the same geographical location as we are right now.
He said, true. Then why do people bother to buy a ticket and spend 18 hours to travel to Canada when the time difference is only seven hours? Why not hire a helicopter, go up, stand still while the Earth is spinning and get down to Canada only after seven hours? Yes, my father, who planted the curiosity seeds in me, he taught me to not simply accept anything as a fact in this world, but look for a reason, a scientific reason behind every single fact.
Why is the sky blue? Why does it turn red at sunset? Why are clouds white?
Why are rain droplets spherical in shape, not cubic? So as I'm truly his daughter, I'm going to do the same today. I'm going to ask you a question, a very simple one of course.
What will happen if I drop this pen? Gravity, right? Simple. Now, what will happen if I drop a nanoparticle?
Does gravity have the same effect? In order to answer this question, we need to know what a nanoparticle is. Nano means one billionth. A nanometer is one billionth of a meter.
To help us imagine nano size, this is a baseball bat, which is about one meter long. Now if you take its length and divide it by 100, you get to the size of my fingertip. which is about one centimeter. Take that and divide it by 10 and you get to the size of neither eye which is only one millimeter.
Take that and divide it by 10 again and you get to the diameter of a human hair which is around 100 micrometer. This might be the smallest division you will be able to see by naked eye. Take that and divide it by 10 again. and you get to the size of a blood cell, which is about 10 micrometer. Take one blood cell and divide it by 10 again.
You get to the diameter of a bacteria, which is only one micrometer. Take one bacteria and divide it by 10 again. You get to the size of a virus, which is around 100 nanometer. Now we are in the scale of nanometer. Pretty close, huh?
but not there yet. All you have to do is to take one virus and this time divide it by 100 and you get to the size of half of a DNA which is only one nanometer. One nanometer it means only five atoms sitting end to end. One nanometer, one billionth of a meter. But what is it all about?
Why we are so obsessed about making things smaller and smaller in size? I understand smaller is lighter, is cheaper, is faster and is smarter. This is what we consider to be the first computer made in 1940s.
Big, complicated and not very smart. Today, every one of you have your own smartphone. a smaller device which is millions of times more powerful than the first computer. But nanotechnology is not simply about making things smaller for the sake of it.
It's because science has different rules in the nanoscale. In fact, if you take materials and start making them smaller and smaller in size, down to nanometers, the materials fall down to the size of a million nanometers. physical and chemical properties change dramatically.
The best example is the gold ring on your finger, which is golden, yellow in color. But a gold nanoparticle is not necessarily golden. It can be red, purple, blue, or even green. This is called quantum effect.
Materials reduced to nano size can suddenly show very different properties than what they show on the micro scale. Now let's get back to that pen and the nanoparticle. In our everyday world, gravity is the most important force we encounter.
It dominates everything around us. Gravity is necessary for rain droplets to fall, or for water to drain, even for our hair to hang down around our head. But on the nanoscale, gravity is nothing. It's negligible.
It's much less important than other forces like electromagnetic forces between atoms and molecules, or the thermal vibration of atoms in a nanostructure. And if I drop this nanoparticle, the dynamics of such a small object would be much more sensitive to the factors like Brownian motion or turbulent diffusion than gravity. In short, the game of science has different rules when you play it in the nanoscale. But if we know these rules, if we learn how to play this game, we can design new materials.
We can manipulate their properties. We can train them and make them behave the way we want them to do. In my laboratory, we are doing this by designing not only small materials, but intelligent nanosensors that can be trained to sniff out your breath.
Yes, your breath. It might seem invisible, but your breath tells a story. And while that story can be used in RBT and get you in trouble, we can use it to save your life.
You know, we smell different when we are sick, although our nose is not strong enough to detect it. But in the same way, The body chemistry changes when we are sick, and as a result of that chemistry change, some ball markers are released into our breath and give us this unique opportunity of detection. disease just by sniffing out the breath.
But there is one big challenge here. These bar markers in human breath, they exist at a very low concentration, down to parts per billion. Here is an example. Aceton is a well-known biomarker for diabetes. Now, if one in a million particles in your breath is acetone, you're healthy.
If two in a million particles of your breath are acetone, you have diabetes. So the biomarkers concentration difference between healthy people and patients is one part per million. million, one ppm.
How small is that? Let me visualize it. The entire Harry Potter series, seven books, has 1,084,170 words, which makes the word Dumbledore on page 17 of Harry Potter and the Philosopher's Stone a little bit less than one ppm. So in order to detect disease using human breath Rather than blood, we need to fabricate and design sensors super sensitive to detect PPM or even less PPB.
Before nanotechnology was impossible to precisely detect such a tiny concentration but today we make sensors like this one which are hundreds of times more accurate than what we need. We can detect two parts in every billion particles in your breath. But how does nanotechnology help us to fabricate such a sensitive, sophisticated sensor?
It's all related to the available surface area. Here we have a cube with a length, width and height of 20 cm. Now what happens to the cube's surface area if I divide it into 8 cubes? You see I'm not changing the material neither its mass nor volume. I'm just creating more surfaces.
So the available surface area is doubled. Now imagine if I divide each of these cubes into smaller and smaller cubes until having cubes with 20 nanometer length. If I do that we're going to have 10 million times larger surface area.
Same material, same mass, same volume. about 10 million times larger surface area. In fact, by shrinking the structural elements of my sensor down to nanoscale, I can significantly increase the available surface area to capture that tiny concentration of biomarker in your breath.
Nanoscience is not just one science. It's a platform that includes biology, chemistry, physics, electronics. medicine, material science and engineering. It's shown its potential to positively impact our quality of life.
And breath analysis, as one of many research areas in this field, can empower us with a better diagnostic technology and can help us to save many, many lives in the near future. Thank you.