UC Irvine

Biological materials rely on intricate organization at every length scale in order to build the complex systems which are key to life. These structures must be able to grow and change in response to a variety of incoming stimuli, in stark contrast to most synthetic materials, which are typically chemically inert once formed. This means that synthetic materials which seek to interface with biology, or biomaterials, are often limited, as they cannot show the same complex behaviors that their native counterparts do. Developing responsive synthetic materials can pave the way for the next generation of biomaterials which are better able to meet the needs of the organism with which they interact.In this work, I explore the interactions of synthetic organic materials with a common biological stimulus, redox. I synthesize responsive materials based on two different motifs, namely perylene diimides and viologens, and demonstrate the interactions of these motifs with the redox stimulus of Shewanella oneidensis. This bacterium can reduce a wide array of electron acceptors through extracellular electron transfer in anaerobic conditions, and I use spectroscopy and rheology to probe the response of materials to this biological stimulus. I then explore an inherent property of supramolecular systems, namely pathway complexity, which results in a material changing properties based on small changes in processing conditions, using rheology and electron microscopy to track these changes and understand their origin. Finally, I synthesize polymeric noncanonical redox cofactors which, through protein engineering, can enable novel biological metabolic pathways, but expose some of the limitations that can arise when attaching these molecules to macromolecular scaffolds.