Engineering Real-Time Sensors and Sustainable Materials for a Healthier Planet

We currently face rising global temperatures, dwindling natural resources, and increasing threats to human and ecological health. To help meet these challenges, my research group engineers biomolecules and microorganisms for real-time bioelectronic sensing and sustainable materials synthesis. We draw inspiration from how proteins and microorganisms transfer electrons to their environments and scaffold advanced materials. By leveraging these natural processes, we engineer microorganisms with specific capabilities to report on sensing through electron transfer and to create multifunctional living materials.

In the first part of my presentation, I will describe how we programmed bacteria to grow into macroscopic materials with tunable mechanical properties. We engineered Caulobacter crescentus to display and secrete an engineered self-interacting protein. This protein assembles cells into hierarchically ordered, centimeter-scale living materials. Manipulating the sequence and domain architecture of the self-interacting protein allows control over the mechanical properties of the resulting materials. This work provides a new platform for growing macroscopic materials with simultaneous control over the materials and biological properties and a route towards sustainable plastics and rubbers.

In the second part of my presentation, I will describe how we have engineered chimeric oxidoreductases for real-time bioelectronic monitoring of therapeutics in blood. We developed a chimeric redox protein that shifts its redox activity and modulates its electrical signal in the presence of estrogen antagonists. We combined this sensor with an organic electrochemical transistor to amplify the electrical signal, increasing the signal-to-noise ratio. This work provides a novel concept for bioelectronic sensing akin to amplitude modulation of radio signals in which an allosteric signal modulates the amplitude of the electrical signal.

Speaker: Caroline Ajo-Franklin, Ph.D., Rice University