The tiny microfliers, whose development by engineers at Northwestern University was detailed in an article published by Nature this week, are being billed as the smallest-ever human-made flying structures.

The devices don’t have a motor, but engineers were instead inspired by the maple tree’s free-falling propeller seeds — technically known as samara fruit. They optimized the aerodynamics of the microfliers so that “as these structures fall through the air, the interaction between the air and those wings cause a rotational motion that creates a very stable, slow, falling velocity,” said John A. Rogers, who led the development of the devices.

“That allows these structures to interact for extended periods with ambient wind that really enhances the dispersal process,” said the professor of materials science and engineering, biomedical engineering and neurological surgery at Northwestern.

The wind would scatter the tiny microchips, which could sense their surrounding environments and collect information. The scientists say they could potentially be use to monitor for contamination, surveil populations or even track diseases.