Incorporating Microbial Pilin-Based Nanowires into a Water-Stable Electronic Polymer Composite

Electrically conductive protein nanowires (e-PNs), microbially produced from a pilin monomer, are a novel, sustainable electronic material that can be genetically tailored for specific functions. e-PNs, expressed with Escherichia coli grown on the biodiesel byproduct glycerol, and mixed with polyvinyl butyral yielded a transparent, electrically conductive water-stable composite.Composite conductivity was adjusted by modifying the e-PN concentration or incorporating e-PNs genetically tuned for different conductivities. Electronic devices in which composites were the sensor component differentially responded to dissolved ammonia over a wide concentration range (1{micro}M-1M). Genetically modifying e-PNs to display an ammonia-binding peptide on their outer surface increased the sensor response to ammonia 10-fold. These results, coupled with the flexibility to design peptides for specific binding of diverse analytes, demonstrate that sustainably produced e-PNs offer the possibility of incorporating multiple sensor components, each specifically designed to detect different analytes with high sensitivity and selectivity, within one small sensor device.