Magnetic shepherd

Engineers have introduced a new magnetic shepherding approach for moving or positioning tiny floating objects found within organisms. The technique will advance potential applications in fields ranging from medicine to nanotechnology.

The authors of a new research article said their method avoids pitfalls of using tiny light beams, electric currents or even a competing magnetic approach to micromanipulate so-called "colloidal" objects.

"Biology is composed primarily of colloidal materials, things larger than a few billionths of a metre that are suspended in solution and don't settle rapidly," said Benjamin Yellen, who developed this "magnetic nanoparticle assembler" technique while obtaining his doctorate at Drexel University.

"They could be cells or large molecules; they are also being investigated for a variety of new devices, such as miniature lasers or semiconducting components," added Yellen, who in September will become an assistant professor of mechanical engineering and materials science at Duke University's Pratt School of Engineering.