Signal Propagation in Multi‐Layer DNAzyme Cascades Using Structured Chimeric Substrates

Signal propagation through enzyme cascades is a critical component of information processing in cellular systems. Although such systems have potential as biomolecular computing tools, rational design of synthetic protein networks remains infeasible. DNA strands with catalytic activity (DNAzymes) are an attractive alternative, enabling rational cascade design through predictable base‐pair hybridization principles. Multi‐layered DNAzyme signaling and logic cascades are now reported. Signaling between DNAzymes was achieved using a structured chimeric substrate (SCS) that releases a downstream activator after cleavage by an upstream DNAzyme. The SCS can be activated by various upstream DNAzymes, can be coupled to DNA strand‐displacement devices, and is highly resistant to interference from background DNA. This work enables the rational design of synthetic DNAzyme regulatory networks, with potential applications in biomolecular computing, biodetection, and autonomous theranostics.     

A rational approach to minimal high-resolution cross-reactive arrays

We report a rational approach to the construction of cross-reactive arrays for steroids consisting of five to seven sensors incorporating modified oligonucleotides. The sensors for our arrays were selected to maximize their differential responses to the two steroids most different in an arbitrarily chosen parameter named "shape-length". The arrays incorporated three previously unreported types of sensors identified through a massive screening effort: (1) three-way junction sensors with neutralized charges within junction; (2) "self-aggregating sensors"; and (3) sensors incorporating fluorophore directly in a three-way junction as a spacer. The arrays were tested on seven steroids and an alkaloid (cocaine) over a range of concentrations, and achieved 92-96% accuracy in class assignments, despite the close structural similarities between steroids.     

Behavior of polycatalytic assemblies in a substrate-displaying matrix

We describe polycatalytic assemblies, comprising one or two streptavidin molecules and two to six attached nucleic acid catalysts (deoxyribozymes), with phosphodiesterase activity. When exposed to a matrix covered at high densities with oligonucleotide substrates, these molecules diffuse through the matrix continuously cleaving the substrate at rates comparable to those of individual catalysts in solution. Rates of diffusion (movement), processivity, and resident times of assemblies can be controlled through the number of catalytic units and the length of substrate/product recognition regions. The assemblies were characterized at the ensemble level using surface plasmon resonance.     

Green corrosion inhibitors of steel based on peptides and their constituents: a combination of experimental and computational approach

Journal of Solid State Electrochemistry - In this work, six groups of non-toxic compounds were tested as inhibitors for mild steel in 1 M HCl solution: glycine (Gly), glutamic acid (Glu),...