A team of US engineers has developed a new technology that uses an electrical field to easily and quickly isolate drug-delivery nanoparticles from the blood.

The electronic chip can also serve as a tool to separate and recover nanoparticles from other complex fluids for medical, environmental and industrial applications.

Nanoparticles, which are generally one thousand times smaller than the width of a human hair, are difficult to separate from plasma - the liquid component of blood - owing to their small size and low density.

Traditional methods to remove nanoparticles from plasma samples typically involve diluting plasma.

These methods either alter the normal behaviour of the nanoparticles or cannot be applied to some of the most common nanoparticle types.

"This is the first example of isolating a wide range of nanoparticles out of plasma with a minimum amount of manipulation," said Stuart Ibsen, post-doctoral fellow at University of California-San Diego.

"We have designed a very versatile technique that can be used to recover nanoparticles in a lot of different processes," he added.

The new nanoparticle separation technology will enable researchers better monitor what happens to nanoparticles circulating in a patient's bloodstream.

Scientists can also use this technology in the clinic to determine if the blood chemistry of a particular patient is compatible with the surfaces of certain drug-delivery nanoparticles.

The chip contains hundreds of tiny electrodes that generate a rapidly oscillating electric field that selectively pulls the nanoparticles out of a plasma sample.

"It's amazing that this method works without any modifications to the plasma samples or to the nanoparticles," Ibsen noted in the study published in the journal Small.