Protein-based materials show a great deal of potential as catalysts, sensors, and optoelectronics, where the unique efficiency, selectivity, or activity of enzymes can be captured to improve the performance of these devices. Control over the structure and orientation of the protein in three dimensions is required to optimize the performance of the devices. One particularly attractive route to do this is the self-assembly of bioconjugates or fusion proteins, where the blocky structure of the molecule can induce self-assembly like a block copolymer. While this strategy is effective for a substantial subset of proteins, not all proteins of interest are amenable to self-assembly as simple bioconjugates, driving the development of novel strategies for nanostructural control in materials. Here, three strategies are demonstrated that create large improvements in the ability of a protein to self-assemble: protein oligomerization, the fusion of a structure-directing group, and the use of polymer-protein-polymer triblock copolymers with strong repulsive interactions between the polymer blocks.
Exploiting these strategies, a small affinity binding protein is self-assembled into nanostructured arrays and demonstrated as a selective biosensor. In particular, self-assembly enables an extremely high density of binding sites at the biosensor surface, which when combined with a size selectivity effect of the nanostructures produces a drop in the limit of detection in blood and urine by two orders of magnitude. Using different structure-directing groups, the effect of nanostructure on biosensor performance is also explored.
Bradley D. Olsen is an associate professor in the Department of Chemical Engineering at MIT. He earned his B.S. in Chemical Engineering at MIT, his Ph.D. in Chemical Engineering at the University of California – Berkeley, and was a postdoctoral scholar at the California Institute of Technology. He started as an assistant professor at MIT in December 2009. Olsen’s research expertise is in materials chemistry and polymer physics, with a particular emphasis on molecular self-assembly, block copolymers, polymer networks and gels, and protein biomaterials. He is a member of the APS and AIChE and a fellow of the ACS and ACS POLY division.
Professor Ed Maginn (email@example.com)
The Thiele Lectureship was established in 1986 to honor Dr. Thiele’s association with Notre Dame’s Department of Chemical and Biomolecular Engineering. The Lectureship is intended to recognize outstanding research contributions by a younger member of the chemical engineering profession. This lecture occurs annually each fall. Learn more about Dr. Thiele here.
Originally published at nano.nd.edu.