Orlin Velev and Vinayak Rastogi don’t use feet, inches or even centimeters to measure the particles they’re working with.
They measure them in billionths of a meter.
The Centennial Campus researchers are working with nanoparticles, which are measured in nanometers. It takes 1 billion nanometers to reach the length of a meter.
But it’s these nanoparticles that have potential application in fields like computer engineering and medicine.
They began working on the project in January 2007. Rastogi was performing experiments to move water droplets onto hydrophobic substrates using chips on which electrodes were installed.
During his research for that experiment, he learned other scientists were attempting to create a three-dimensional assembly of nanoparticles. With their methods, they weren’t able to get these nanoparticles to maintain a spherical formation.
It’s this type of formation, or close to it, that Rastogi figured he could accomplish using the same hydrophobic substrates he was using in his original project.
So the researchers began to experiment with latex and gold nanoparticles. Latex nanoparticles, Rastogi said, range in size from 320 to 1000 nanometers. Gold nanoparticles are even smaller, Rastogi said, and have a 20-nanometer diameter.
“The beauty of it is that it’s a very simple procedure,” Velev said.
They suspend these particles in water and then place water droplets on the hydrophobic substrate. The surface naturally repels the water, causing the water surrounding the particles to evaporate. As it does, the particles move closer and closer together.
“As the droplets are drying, it’s compressing the size by shrinking the particles,” Velev said. “They’re assembled into very well-organized particles.”
The result is technically called a supraparticle — a particle that’s composed of multiple nanoparticles — but also goes by “nanojewel.”
It is almost spherical, but the nanojewel is slightly flat on the bottom, according to a report published by Rastogi, Velev and researchers from Arizona State University and the Los Almos Labratory. Depending on the size of the latex particles, Rastogi said scientists will be able to alter the nanojewel’s size, shape and even composition.
And that’s what makes it an important contribution to Velev and Rastogi’s field of research as well as areas like computer engineering and medicine, although how it is made “depends on the ultimate goal.”
For computer engineering purposes, Rastogi said these nanojewels’ properties make them one of the first steps toward creating light-based computers that run using light, not electricity. This kind of computer runs billions of times faster than electricity-powered computers, Rastogi said.
Nanojewels can also be used for medicinal purposes. Rastogi said that, though the same process, scientists can suspend medicinal and magnetic particles with other nanoparticles to create a nanojewel that delivers the same medicine but can also “allow remote manipulation”
So the drug will flow through the blood stream like a normal medicinal carrier, but doctors and surgeons will be able to use a magnet to guide its path and direct it to a specific area of the body.
Although Rastogi said he and Velev will not actively work with nanojewels for these purposes, they have provided the means for practical, concrete application of supraparticles.
Other scientists who tried to extract suspended nanoparticles from a liquid had to find a way to get rid of the liquid, Rastogi said. Until this project, that method could be either benign or could be harmful to the environment.
The Centennial Campus researchers’ method eliminates environmental risk and also streamlines the process so that scientists can mass produce nanojewels.
“Our method creates a ready-to-use, special product,” Rastogi said. “It’s very easy to implement, and it’s very easy to reproduce. You can control the size and you can make multiple supraparticles on the same substrate at the same time.”
If scientists and researchers wish to use the nanojewels for other purposes — such as light-powered computers and magnetic drug carriers — they have to be able to quickly and easily mass produce nanojewels.
Commercializing the product and the process will make nanojewels available to more people at a smaller cost. In this way, scientists, engineers, doctors and surgeons might be able to use nanojewels in their lines of work on a frequent basis.
“If you want to commercialize it, you have to reproduce it,” Rastogi said.