BARIUM|Squishy and mushroom-shaped,
flexible microgels hold promise as customized drug
delivery vehicles and building blocks for tissue
engineering. Now, Arezoo Ardekani and her team
have created a new, relatively simple method for
producing these shape-shifters that could greatly
widen their use.
Using microfluidics, in which tiny tubes and
channels control micro-quantities of fluids, the
researchers mix sodium alginate and polyNIPAAm
into uniform droplets. They then inject the droplets
into a collecting solution of glycerol and barium
As the barium ions turn the droplets into gel
with new chemical bonds to hold it together, the
The Shape-Shifting Promises of Microgels
interfacial effects cause the droplets to change
shape. The resulting mushroom-shaped, squishy
particles can be shaped further by varying the
concentration of glycerol in the collecting solution.
“The novelty of this work is that it is very simple
to generate different shapes just by changing
the concentration of glycerol,” says Ardekani, an
assistant professor of mechanical engineering.
Because microgels also can phase-separate,
producing a double-sided, or Janus, surface with
different physical properties, they could be used to
co-deliver two different kinds of medications. Cells
also might be encapsulated into the microgels for
tissue engineering.| L. T.