Bioreplication Creates Blood-Cell-Like Silica Particles

Materials scientists have to work hard to synthesize inorganic particles with shapes more complicated than spheres or rods. But cells easily adopt a range of interesting shapes that impart specific functions—ones that researchers would like to mimic. Now a team reports using red blood cells as templates to make hard silica particles with novel structures (J. Am. Chem. Soc. 2014, DOI: 10.1021/ja506718z).

Materials scientist Bryan Kaehr and his colleagues at Sandia National Laboratories, in Albuquerque, N.M., synthesized these asymmetric particles by first treating disc-shaped red blood cells with different chemicals to force them to change shape. A cationic lipid made the cells transform into a cup shape, known as a stomatocyte. An anionic lipid combined with high salt and adenosine triphosphate depletion produced two spherical shapes, echinocytes and spherocytes. The team fixed the blood cells in formaldehyde and then soaked them in a silica solution overnight. The silica formed a hard shell from which the soft cell could be extracted, leaving the silica replicate.

“We can replicate all of the surfaces, both internal and external,” Kaehr says, noting that the group has succeeded in replicating single cells all the way up to small organisms—a chicken embryo, for example.

Locking the particles into a specific shape offers a chance to study the morphological and mechanical properties of cells as they interact with one another, Kaehr says. He next wants to preserve the cells’ biological functions in the silica replicates.