Mixed Ionic and Electronic Charge Transport in Conductive Protein Fibers Revealed with DC Electrical Measurements.

Naturally conductive protein nanowires have inspired efforts to engineer electrical conductivity into synthetic fibrous proteins for the development of bioelectronic materials and devices. A comprehensive analysis of charge transport in these systems requires a combination of various measurement methods, instruments and electrode designs. Measurements under direct current (DC) typically focus on charge transport without distinguishing between charged species, requiring alternating current (AC) and electrochemical methods to probe additional phenomena.

M13 bacteriophage as a versatile platform for the creation of new materials via genetic engineering.

M13 bacteriophages form self-assembled nanorods with the ability to self-assemble into complex materials with higher-order structures. These features make them useful templates for material fabrication. Their use in soft materials, bio-nano systems, and biomedical applications is well established.

Fabrication of Curli Fiber-PEDOT:PSS Biomaterials with Tunable Self-Healing, Mechanical, and Electrical Properties.

Poly(3,4-ethylenedioxythiophene) polystyrenesulfonate (PEDOT:PSS) is a highly conductive, easily processable, self-healing polymer. It has been shown to be useful in bioelectronic applications, for instance, as a biointerfacing layer for studying brain activity, in biosensitive transistors, and in wearable biosensors. A green and biofriendly method for improving the mechanical properties, biocompatibility, and stability of PEDOT:PSS involves mixing the polymer with a biopolymer.

Fabrication of fluorescent pH-responsive protein-textile composites.

Wearable pH sensors are useful tools in the healthcare and fitness industries, allowing consumers to access information related to their health in a convenient manner via the monitoring of body fluids. In this work, we tailored novel protein-textile composites to fluorescently respond to changing pH. To do so, we used amyloid curli fibers, a key component in the extracellular matrix of Escherichia coli, as genetic scaffold to fuse a pH-responsive fluorescent protein, pHuji.

Bound detergent molecules in bacterial reaction centers facilitate detection of tetryl explosive.

Bacterial reaction centers (BRC) from Rhodobacter sphaeroides were found to accelerate, about 100-fold, the reaction between tetryl (2,4,6-trinitrophenylmethylnitramine) explosive and n-lauryl-N-N-dimethylamine-N-oxide (LDAO) that results in the formation of picric acid-like product with characteristic UV-VIS absorption spectrum with peaks at 345 and 415 nm. Moreover, this product also affects the spectra of BRC cofactors in the NIR spectral region and stabilizes the conformational changes associated with slow charge recombination. The evolution of the NIR absorption changes correlated with the kinetics of the product formation.