Explore the vast range of titles available.

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. Engineered amyloids form macroscopic and environmentally resistant aggregates that we isolated to use as stand-alone hydrogel-based sensors, and that we trapped within textile matrices to create responsive bio-composites. We showed that these composites were mechanically robust and vapor-permeable, thus exhibiting favorable characteristics for wearable platforms. CsgA–pHuji fibers integrated in the textile allowed the final device to respond to pH changes and distinguish between alkaline and acidic solutions. We demonstrated that the resulting composites could sustain their fluorescence response over days, and that their sensing ability was reversible for at least 10 high/low pH cycles, highlighting their potential for continuous monitoring. Overall, we introduced a biosynthesized amyloid-based textile composite that could be used as biosensing patch for a variety of applications in the smart textile industry.

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. Comparison between the wild-type and the R26 carotenoid-less strain indicates that tetryl-LDAO reaction is roughly five times faster for R26, which allows for identifying the carotenoid binding site as the optimal reaction site. Another, less-defined reaction site is located in the BRC’s hydrophobic cavity. These effects are highly selective for tetryl and not observed for several other widespread nitric explosives; slowed-down charge recombination allows for distinguishing between tetryl and QB-site herbicides. The current limit of detection is in the ppb range or ~ 100 nM. Details of the molecular mechanisms of the reactions and perspectives of using these effects in bioassays or biosensors for explosives detection are also discussed.