Engineers have developed chip-based technology that uses an oscillating electrical field to quickly and easily isolate nanoparticles from blood.
In the journal Small, the team from the University of California-San Diego says the new tool could be used to remove drug-carrying nanoparticles from blood.
Nanoparticles – tiny objects 1,000 times smaller than the thickness of human hair – are increasingly finding their way into medicine, for example as a vehicle for precisely targeting drug delivery inside cells or to break up blood clots.
A tool that quickly removes nanoparticles from blood would be useful for researchers who devise and study nanoparticle drug-delivery systems and want to know how it affects the nanoparticles.
For example, one of the things that can happen is that blood proteins can stick to the nanoparticles and make them less effective.
Another way the tool could be used is to find out if the blood chemistry of a patient is compatible with the surfaces of the type of nanoparticle in the drug delivery under consideration.
First author Dr. Stuart Ibsen, a nanoengineering researcher, says theirs is the first example of removing a wide range of nanoparticles out of plasma with minimum manipulation.
“It’s amazing that this method works without any modifications to the plasma samples or to the nanoparticles,” he adds.
Current methods for removing nanoparticles from blood are cumbersome and time-consuming.
For example, in one way of removing nanoparticles from plasma, the plasma has to be diluted first, then mixed with a highly concentrated sugar solution, and then spun in a centrifuge. Another method requires that the nanoparticles are tagged with an agent that sticks to their surface.
But these methods are not satisfactory since they can change the physical properties of the nanoparticles, or in many cases, they cannot be used with typical types of nanoparticles.
For the study, the researchers used a dime-sized electric chip that contains hundreds of tiny electrodes that set up a rapidly oscillating electric field that drags the nanoparticles out of a plasma sample.
The team tested the chip on a drop of plasma spiked with nanoparticles and watched as it completed the extraction within 7 minutes.
The chip uses breakthrough technology that works despite the high salt level in blood plasma. It exploits the fact that when the field is established, the positive and negative charges in the nanoparticles line up at a different speed to the charges in the molecules of the plasma.
This imbalance causes an attraction between the nanoparticles and the electrodes, and as the field oscillates at 15,000 times per second, the particles are pulled toward the electrode, leaving the plasma behind.
The technology might also be useful in other medical, environmental and industrial applications where there is a need to remove nanoparticles from complex fluids. Dr. Ibsen concludes:
“We’ve designed a very versatile technique that can be used to recover nanoparticles in a lot of different processes.”
Earlier this year, Medical News Today learned how engineered nanoparticles can enter water supplies. In the journal Environmental Engineering Science, researchers from the University of California-Riverside say their findings raise concerns about whether current water treatment facilities can adequately remove engineered nanoparticles.