In order to develop a successful therapy that utilizes the immune system to treat a condition or protect against a disease, it is not enough simply to raise a strong immune response. Beyond this, an elicited response must possess the correct combination of features necessary for efficacy. Some of these features may include memory or lack thereof, proper Th1/Th2 polarization, engagement of CD8 cells or lack thereof, duration of the response, overall antibody titer and affinity, elicitation of particular antibody isotypes, and a range of other aspects that combine to provide an overall immune phenotype. Most current vaccine platforms and other immunomodulating platforms are not designed to be able to adjust such combinations of features smoothly and simultaneously, yet often the success or failure of a new immunotherapy hinges on first discovering and then achieving a narrowly defined immune phenotype. In our group we are designing supramolecular biomaterials, primarily from peptides and proteins, that facilitate such immunological tuning. Materials that will be described in this talk include beta-sheet fibrillizing peptides, nanofibers created from alpha-helical coiled coils, and expressed proteins that can insert into supramolecular assemblies. In each case, assembling domains are designed that are amenable to functionalization with a wide variety of immune epitopes (CD4, CD8, or B cell), as well as immunomodulating components and adjuvants. Overall, we have found such peptide assemblies to elicit a relatively non-inflammatory and undifferentiated T cell phenotype that facilitates their use for therapeutic vaccination and for subsequently adjusting the response into more specific phenotypes. This talk will highlight the development of these materials towards a range of therapeutic goals with varied immunological requirements, including chronic inflammation, cancer, influenza, and other infectious diseases.
Although the chemical, physical, and mechanical properties of a polymer are the most vital factors in determining utility, another important constraint that must be considered is the cost of the material. The best way to create inexpensive new polymers is to start with large-scale commodity monomers, rather than rely on the development of new-to-the-world monomers. The focus of our work is the development of new synthetic methods for polymer synthesis, where known organic feedstocks are combined in alternative ways to make new macromolecular materials. We accomplish this through the development of metal-based catalysts that exhibit unique reactivity. In this presentation, the discovery, development and application of new catalysts for polymerization will be presented. The development of new methods for the synthesis of sustainable polymers will also be discussed.
Associate Professor; Duke University
Associate Professor; University of North Carolina at Chapel Hill
Although particle roughness is encountered in many technological and engineering applications, its role in the flow and dynamics of concentrated colloidal suspensions is not well understood. Here, we present recent experiments and simulations that demonstrate that surface roughness is key to shear thickening and jamming in colloidal suspensions. Smooth and rough polymeric colloids are fluorescently dyed and suspended in a solvent that is refractive index and density matched. Fast confocal microscopy shows that there is a significant increase in the rotational relaxation time of rough colloids, while translational dynamics remain unaffected. Moreover, we observe a transition from continuous to discontinuous shear thickening in flowing suspensions when the root-mean-squared roughness is increased above a critical value. We present a physical rationale behind these observations by considering the competition of lubrication and friction in concentrated suspensions. This earlier work leads to our current projects on the tribology of patterned soft substrates and synthesis of stimuli-responsive colloids.
The need for new lightweight polymeric materials with the ability to perform both structural and functional tasks is increasing rapidly. Application areas that would benefit from such materials include structural composites, energy generation, energy storage, water purification and gas separation. In this contribution we will report on how new lyotropic and thermotropic high-performance liquid crystal polymer chemistries can be used to design new functional materials. We will show that sulfonated all-aromatic liquid crystal polymers (LCPs) are excellent candidates when it comes to designing new classes of molecular composites, e.g. ionic liquid gels for Li-ion battery applications and graphene-based nanocomposites for barrier film applications and electrodes. The synthesis of novel thermotropic main-chain liquid crystal (AB)n-multiblock copolyesterimides has enabled us to design a new family of single component high-temperature shape memory polymers. ‘Classic’ all-aromatic polyazomethines can be used for structural applications but with some backbone tweaking they can be used as cheap photovoltaic and electrochromic building blocks.
Tisch University Professor; Cornell University
Assistant Professor; North Carolina State University