January 21, 2021
Assistant professor Eleftheria Roumeli and research assistant professor Shuai Zhang have been awarded UW’s Royal Research Award (RRF). The RRF supports faculty, particularly in disciplines for which external funding opportunities are minimal; for faculty who are junior in rank; and in cases where funding may provide unique opportunities to increase applicants’ competitiveness for subsequent funding.
Biocomposite materials from algae cells: Sustainable and hierarchical
The long-lasting detrimental effects of plastics manufacturing and consumption led to the introduction of plant-based materials as sustainable and efficient alternatives in numerous applications. Our group utilizes plant cells to fabricate entirely biodegradable biocomposite materials which have mechanical properties comparable to petroleum-derived plastics. We study how to control the performance of those natural biocomposites by implementing a hierarchical design associated with the cell arrangement in the microscale.
This project will explore algae cells as the fundamental material building block for novel biocomposites. Given the abundance of marine algae cultures and their biosynthetic abilities, these organisms already revolutionized the food, pharmaceuticals and biofuels industries. Here we will utilize algae cells as a building block for new nanocomposites and use 3D-printing to control their arrangement in the micro-scale. The produced structures will have a hierarchical design governed by the spatial distribution of the nanofibrillar structural elements, which will allow us to tune the mechanical properties of these entirely biodegradable nanocomposite materials, thus offering a variety of sustainable alternatives to non-environmentally friendly plastics.
Elucidating the conformational switch of R-bodies: A pH-responsive shape-shifting protein machine
R-bodies are protein polymers, assembled by bacterial endosymbionts of ‘killer’ Paramecium strains, which have the capability to shift shape between a contracted coil and an elongated helical ribbon in response to pH changes. As a candidate for shape-shifting polymer machines, they have unique advantages, including outstanding conformational robustness and reversibility, the ability to generate strong mechanical forces from simple chemical energy, (sub)micron scale dimensions, and vast potential for bioengineering due to a wide range of mutations. However, the structural basis and physiochemical mechanism underlying the massive conformational transition in response to pH is largely unknown.
We will fill that gap by measuring the extent and rate of transformation, as the strength of the stimulus is varied via solution pH and electrolyte type/concentration. In-situ high-resolution and high-speed atomic force microscopy (AFM) and AFM-based 3D fast force mapping will be used to directly observe R-body structural transformations at the molecular level in real time and map the changes surrounding solution structure associated with pH and electrolyte changes. The results will provide fundamental insights into R-bodies as biomolecular motors and shape-shifting polymer machines and enable artificial engineering of biomolecules to generate impressive conformational transitions and consequent forces.