Twisted Nanofibers

Caption:
False color image of peptide nanofibers that have bundled and twisted together. Upper right panel shows that the individual nanofibers (~10nm diameter) start bundling in small groups of two or three nanofibers then these bundles begin twisting with neighboring bundles creating large braided structures similar to the organization of fibers in common rope.

Ronit Freeman
Mark McClendon
Advisor: Samuel Stupp
Simpson Querrey Institute for BioNanotechnology
Northwestern University, Evanston, IL 60208

Laboratory website: http://stupp.northwestern.edu/group/index.html

Technique: Scanning Electron Microscopy, false color added with Photoshop

Description:
Growing artificial organs and tissues is one challenge that nanotechnology strives to accomplish. The nanofibers shown here are made from biocompatible amino acids linked together (a.k.a. peptides). These nanofibers make excellent gels that can be used to grow cells and regenerate living tissue. The challenge is that every type of cell prefers a different gel stiffness. But these new nanofiber gels allow us to precisely tune the gel stiffness by controlling the amount of twisting in the nanofiber bundles. The twisted bundling behavior is a result of the attractive forces between the individual nanofibers. By introducing different soluble molecules to the gels we can switch on and off this twisting behavior thereby changing the gel stiffness for whatever specific cells are being cultured. Having this dynamic material on which to grow cells allows us to make very complicated scaffolds required for growing artificial tissues.
More Info:
Advanced Materials 26(11), (2014) 1642-1659.
Biomaterials 43(20), (2013) 4749-4757.
Biomaterials 33(23), (2012) 5713-5722.

Funding Source: National Institute of Health (NIH), Institute: National Heart, Lung, and Blood Institute (NHLBI), Project # 1R01HL116577-01A1, Program Officer: Danthi, Narasimhan