Glasses with high antimicrobial efficacy were developed in the Fe2O3-CuO-P2O5 ternary system to mitigate fomite-mediated transmission of infectious diseases in high-risk settings such as hospitals, daycares, and nursing homes. Binary CuO-P2O5 glasses were not durable enough for use as high touch point articles, so Fe2O3 was added to the compositions to increase the chemical durability. The amount of Cu leachate decreased by at least 3 orders of magnitude when Fe2O3 was increased from 0 to 13.1 mol%. At the highest Fe2O3 contents and corresponding highest durability, the glass was no longer able to pass a test of antimicrobial efficacy with < 3 log kill compared to > 5 log kill for all other compositions. Ab-initio molecular dynamics simulations showed increasing bridging oxygen species at the expense of non-bridging oxygen species with the increase in Fe2O3 content, showing that the glasses exhibited increased chemical durability because they were more interconnected and structurally bound. Experimental results with glasses at fixed CuO and decreasing Fe2O3 confirmed that Fe2O3 content (not CuO) controlled the Cu release rate and, thus, the antimicrobial efficacy of the glasses. The significance of the oxidation state of the leached Cu was overwhelmed by the importance of the amount of Cu leachate.

This work presents fundamental understanding of the correlation between nanoindentation hardness and practical scratch resistance for mechanically tunable anti-reflective (AR) hardcoatings. These coatings exhibit a unique design freedom, allowing quasi-continuous variation in the thickness of a central hardcoat layer in the multilayer design, with minimal impact on anti-reflective optical performance. This allows detailed study of anti-reflection coating durability based on variations in hardness vs. depth profiles, without the durability results being confounded by variations in optics. Finite element modeling is shown to be a useful tool for the design and analysis of hardness vs. depth profiles in these multilayer films. Using samples fabricated by reactive sputtering, nanoindentation hardness depth profiles were correlated with practical scratch resistance using three different scratch and abrasion test methods, simulating real world scratch events. Scratch depths from these experiments are shown to correlate to scratches observed in the field from consumer electronics devices with chemically strengthened glass covers. For high practical scratch resistance, coating designs with hardness >15 GPa maintained over depths of 200–800 nm were found to be particularly excellent, which is a substantially greater depth of high hardness than can be achieved using previously common AR coating designs.

Touchscreens are now commonplace around the world, and easy-to-clean (ETC) coatings are integral in ensuring an enhanced usability and interactivity with these devices. In the present work, we evaluate the durability and study the wear mechanisms of a fluorine-containing easy-to-clean coating on glass using an in situ tribometer (TribTik). The TribTik is equipped with a microscope lens and camera system that allows one to image, in real time, the contact area between the glass substrate and the abrading counterpart. Through this unique combination, the instantaneous coefficient of friction and the contact area's status can be monitored and correlated in situ. The in situ monitoring enables one to stop the abrasion cycles at critical stages of the wear process so that the morphology and composition of the wear tracks can be examined in an effort to understand the wear mechanisms of the ETC. We demonstrate that changes in the instantaneous coefficient of friction (COF) are correlated with changes in the in situ images. Critical stages of wear evolution are also identified via optical microscopy, scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDS) and Raman analyses. The evolution of the ETC wear mechanism, from start to finish, was found to be described by the following sequence: (1) generation of unconsolidated debris, (2) formation of a layered tribofilm, (3) cracking of the tribofilm, and (4) general failure of the ETC and subsequent damage to the underlying glass substrate. Our study shows that, TribTik, a tribometry system with real-time imaging capability, is a powerful tool to characterize the tribological properties of coatings on touchscreens and/or display substrates.

A system was developed to characterize surface damage on samples subjected to abrasion testing. It is optimized to correlate directly with human visual rankings while providing repeatable quantitation of damage.

DNAzymes are known to bind metal ions specifically to carry out catalytic functions. Despite many studies since DNAzymes were discovered nearly two decades ago, the metal-binding sites in DNAzymes are not fully understood. Herein, we adopt uranyl photocleavage to probe specific uranyl-binding sites in the 39E DNAzyme with catalytically relevant concentrations of uranyl. The results indicate that uranyl binds between T23 and C25 in the bulge loop, G11 and T12 in the stem loop of the enzyme strand, as well as between T2.4 and G3 close to the cleavage site in the substrate strand. Control experiments using two 39E DNAzyme mutants revealed a different cleavage pattern of the mutated region. Another DNAzyme, the 8-17 DNAzyme, which has a similar secondary structure but shows no activity in the presence of uranyl, indicated a different uranyl-dependent photocleavage as well. In addition, a close correlation between the concentration-dependent photocleavage and enzymatic activities is also demonstrated. Together, these experiments suggest that uranyl photocleavage has been successfully used to probe catalytically relevant uranyl-binding sites in the 39E DNAzyme. As uranyl is the cofactor of the 39E DNAzyme as well as the probe, specific uranyl binding has now been identified without disruption of the structure.

Der gezielte Entwurf funktioneller Enzyme mit hohem Turnover, insbesondere solcher mit komplexem aktivem Zentrum wie respiratorischer Oxidasen, ist eine Herausforderung. Durch Einführung zweier His- und eines Tyr-Restes in Myoglobin wurden Enzyme erhalten, die O2 in mehr als 1000 Turnovers und mit minimaler Freisetzung reaktiver Sauerstoffspezies zu H2O reduzieren (rote Linie im Schema). Die Platzierung des Tyr-Restes ist entscheidend für die Aktivität. Detailed facts of importance to specialist readers are published as ”Supporting Information”. Such documents are peer-reviewed, but not copy-edited or typeset. They are made available as submitted by the authors. Please note: The publisher is not responsible for the content or functionality of any supporting information supplied by the authors. Any queries (other than missing content) should be directed to the corresponding author for the article.

The natural chirality of DNA and RNA aptamers has been used to develop fluorescent agents to determine the enantiomeric ratio of adenosine and arginine, respectively. The quantification is based on structure-switching DNA or RNA aptamers labeled with fluorophore and quencher, allowing chiral detection down to 0.1 : 99.9 (L : D) for arginine after calibration. Such a method provides a general platform for simple, low-cost and high throughput detection and quantification of chirality of a broad range of molecules.