Self-Assembly of Large and Small Molecules into Hierarchically Ordered Sacs and Membranes
Ramille M. Capito,1
Helena S. Azevedo,1,2
Yuri S. Velichko,3
Alvaro Mata,1
Samuel I. Stupp1,3,4,5*
We report here the self-assembly of macroscopic sacs and membranes at the interface between two aqueous solutions, one containing a megadalton polymer and the other, small self-assembling molecules bearing opposite charge. The resulting structures have a highly ordered architecture in which nanofiber bundles align and reorient by nearly 90° as the membrane grows. The formation of a diffusion barrier upon contact between the two liquids prevents their chaotic mixing. We hypothesize that growth of the membrane is then driven by a dynamic synergy between osmotic pressure of ions and static self-assembly. These robust, self-sealing macroscopic structures offer opportunities in many areas, including the formation of privileged environments for cells, immune barriers, new biological assays, and self-assembly of ordered thick membranes for diverse applications.
1 Institute for BioNanotechnology in Medicine, Northwestern University, Chicago, IL 60611, USA.
2 3B's Research Group, Biomaterials, Biodegradables and Biomimetics, Department of Polymer Engineering, University of Minho, Braga, Portugal.
3 Department of Materials Science and Engineering, Northwestern University, Evanston, IL 60208, USA.
4 Department of Chemistry, Northwestern University, Evanston, IL 60208, USA.
5 Department of Medicine, Northwestern University, Chicago, IL 60611, USA.
* To whom correspondence should be addressed. E-mail: s-stupp{at}northwestern.edu
