News & Events

Cellulose Nanocrystals: From Self-assembly to Structurally Anisotropic Nanofibrillar Hydrogels

Date: 
Tuesday, February 26, 2019 - 12:45 to 14:00
Speaker: 
Dr. Eugenia Kumacheva I 3M Lecture
Affiliation: 
Department of Chemistry, University of Toronto
Event Category: 
LMC - Lectures in Modern Chemistry
Location: 
Chemistry B250

Abstract:

Cellulose nanocrystals (CNCs), highly crystalline rod-like nanoparticles, have recently attracted revived research interest, both in fundamental studies of self-assembly of nanoparticles and in the applications of CNCs in materials science.

This presentation will highlight two aspects of our work in these research fields. 

Self-assembly of CNCs. The organization of nanoparticles in constrained geometries is an area of fundamental and practical importance, since under confinement, nanocolloids exhibit new modes of self-assembly. We examined the organization of cholesteric liquid crystals formed by CNCs under spherical confinement and observed new CNC self-assembly modalities of polymer, metal, carbon and metal oxide nanoparticles. The resulting hybrid cholesteric droplets exhibited fluorescence, plasmonic properties and magnetic actuation.  Furthermore, we observed interactive morphogenesis between the CNC host and nanoparticle guest. This work was extended to the preparation of nanocolloidal cholesteric microgels with catalytic properties. These results advance our understanding of how the interplay of order, confinement and topological defects affects the morphology of hybrid soft matter materials.

Hydrogels derived from CNCs. Synthesis and fabrication of man-made hydrogels mimicking fibrous biological tissues is an important and challenging task. We developed CNC-based nanofibrillar hydrogels and used them as scaffolds for cell culture. One example of such scaffold is a supramolecular temperature-responsive hydrogel formed by CNCs tethered with polymer molecules. A filamentous hydrogel was formed at 37 oC from an aqueous CNC suspension and used for cell encapsulation and growth. On demand, the cells were released by lowering the temperature and subsequently transferred to another scaffold. The second hydrogel was formed by covalent crosslinking of gelatin and CNCs carrying surface aldehyde groups. By using 3D printing, we generated structurally anisotropic CNC-derived hydrogels with gradients in composition, structure and properties.

Bio:

Eugenia Kumacheva is a University Professor in the University of Toronto and Canada Research Chair in Advanced Polymer Materials (Tier 1). Her primary research interests are in the materials science of soft matter, including polymer and nanoscience, and microfluidics.

Eugenia has published >250 papers (h-index=78, with >60 citations/paper, 9 book chapters, and 2 books. She holds >4 patents and is a founder of a company FlowJEM. She has given >300 invited, keynote and plenary lectures, as well as public lectures. 

Among her awards are Killam Fellowship, Macromolecular Science and Engineering Award, Clara Benson Award (CIC), Schlumberger Scholarship (U.K.), International Chorafas Foundation Award in Physics and Engineering (Switzerland), Humboldt Research Award (Germany) and the 2009 L'Oreal-UNESCO Award “For Women in Science” (given to 5 laureates in the world). She is a Fellow of the Royal Society of Canada and Royal Society (U.K.). In 2017, she was recipient of the Canada Institute for Chemistry (CIC) medal, "a mark of distinction and recognition to a person who has made an outstanding contribution to the science of chemistry or chemical engineering in Canada, this is the CIC’s top award."