Credit: © 2009 WILEY

Micro- and nanoparticles are being investigated for use as capsules for delivering drugs or for bioimaging, with their shape often as important as their size. Hollow or core–shell spheres can be internally functionalized to carry drugs or imaging agents. Particles with different compartments have been made, but only spherical ones thus far.

Now, Joerg Lahann and colleagues from the University of Michigan have made microcylinders with controlled size and shape that have two, three or even four compartments (pictured; Angew. Chem. Int. Ed. 48, 4589–4593; 2009). They used electrohydrodynamic spinning from two separate jets to create sectioned polymer microfibres and then cut them into cylinders around 50 μm long by cryosectioning. The polymer was a lactide–glycolide copolymer, chosen for its biodegradable properties that are useful in many biomedical applications.

Loading the different compartments with different dye molecules meant that the structures were clearly visible under confocal laser scanning microscopy. The number and arrangement of the compartments could be controlled by altering the electrospinning process.