Polymer spheres with a sugar coating on the outside and plastic coating on the inside have been made by European scientists. This gives them dual functionality to target and deliver drugs. 

Helmut Schlaad from the Max Planck Institute of Colloids and Interfaces, Potsdam, and colleagues from Germany and Switzerland made the spheres by dissolving glycosylated polybutadiene-poly(ethylene oxide) block copolymers in water. When dissolved, the copolymers spontaneously formed hollow colloids called vesicles with a glucose coating on the outside and a poly(ethylene oxide) coating on the inside. 

The polymer vesicles could be used as living cell mimics or drug delivery vessels. Thanks to their adjustable properties - stability, fluidity and dynamics - they could be better models for biomedical research than vesicles made from the phospholipids found in cells. Usually, the coatings on both sides of a vesicle's membrane are the same. As the outside and inside of Schlaad's vesicles are different, it may be possible to assign different tasks to each side. 'It would be very interesting to have vesicles with an asymmetric membrane for many applications, especially in life sciences,' says Schlaad.

For example, they could be used to target drugs and biomolecules to injured or cancerous tissues, says René Roy, an expert in carbohydrate chemistry and glycobiology at the University of Québec, Montréal, Canada. 'Schlaad's compounds have great potential in emerging glycobiology research. I see them having superb opportunities in carbohydrate-based vaccine technologies,' he adds. 

Schlaad says that in the future, he hopes to generate smart vesicles with pH- or temperature-responsive membranes. 'External stimuli shall be used to induce either a morphological change or vesicle collapse to trigger cargo molecule or drug release,' he says. 

Elizabeth Davies

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