The chemical affinity of single-stranded DNA (ssDNA) to adsorb to the surface of single-walled carbon nanotubes (SWCNTs) is used for SWCNT purification, separation and in bio-devices. Despite the popularity of research on SWCNT-ssDNA conjugates, very little work has studied the removal of adsorbed ssDNA on SWCNTs. This paper reports a comprehensive study of biological, physical and chemical treatments for the removal of ssDNA from SWCNT-ssDNA suspensions. These include enzymatic cleavage, heat treatment under vacuum up to 400 °C, chemical treatments with high or low pH, oxidizing conditions, and high-ionic-strength solvents. Complimentary characterization techniques including fluorescence from a DNA-intercalating dye (YO-PRO-1) and photoelectron spectroscopy are used to exhaustively study and compare the methods investigated. Enzyme treatment is found to remove the phosphate backbone only, leaving nucleosides adsorbed to SWCNTs. Heating in inert atmosphere is ineffective at removing ssDNA. Acid, base and oxidative treatment are found to be effective for the removal of ssDNA from SWCNTs. Where possible the mechanism of desorption is described and from the findings suggestions for "best practices" are provided.

The exploration of new efficient OER electrocatalysts based on nonprecious metals and the understanding of the relationship between activity and structure of electrocatalysts are important to advance electrochemical water oxidation. Herein, we developed an efficient OER electrocatalyst with nickel boride (Ni3 B) nanoparticles as cores and nickel(II) borate (Ni-Bi ) as shells (Ni-Bi @NB) via a very simple and facile aqueous reaction. This electrocatalyst exhibited a small overpotential of 302 mV at 10 mA cm-2 and Tafel slope of 52 mV dec-1 . More interestingly, it was found that the OER activity of Ni-Bi @NB was closely dependent on the crystallinity of the Ni-Bi shells. The partially crystalline Ni-Bi catalyst exhibited much higher activity than the amorphous or crystalline analogues; this higher activity originated from the enhanced intrinsic activity of the catalytic sites. These findings open up opportunities to explore nickel(II) borates as a new class of efficient nonprecious metal OER electrocatalysts, and to improve the electrocatalyst performance by modulating their crystallinity.

Fine control over the architecture and/or microstructure of synthetic polymers is fast becoming a reality owing to the development of efficient and versatile polymerization techniques and conjugation reactions. However, the transition of these syntheses to automated, programmable, and high-throughput operating systems is a challenging step needed to translate the vast potential of precision polymers into machine-programmable polymers for biological and functional applications. Chain-growth polymerizations are particularly appealing for their ability to form structurally and chemically well-defined macromolecules through living/controlled polymerization techniques. Even using the latest polymerization technologies, the macromolecular engineering of complex functional materials often requires multi-step syntheses and purification of intermediates, and results in sub-optimal yields. To develop a proof-of-concept of a framework polymerization technique that is readily amenable to automation requires several key characteristics. In this study, a new approach is described that is believed to meet these requirements, thus opening avenues toward automated polymer synthesis.

Well-defined steroid hormone dimers and organogels were produced via a facile and scalable synthesis using oxime click chemistry. The versatile synthetic procedure extends to a wide range of hormones and linker groups exemplified here through the synthesis of cortisol- and progesterone-dimers linked via hydrophobic, hydrophilic or functional groups. This method was also extended to the synthesis of cortisone-based organogels. Owing to the dynamic nature of the oxime bond, the hormone-based materials are degradable via acidic hydrolysis and transoximination representing new materials for the controlled release of steroid hormones.

Cardiovascular diseases, including myocardial infarction, are the cause of significant morbidity and mortality globally. Tissue engineering is a key emerging treatment method for supporting and repairing the cardiac scar tissue caused by myocardial infarction. Creating cell supportive scaffolds that can be directly implanted on a myocardial infarct is an attractive solution. Hydrogels made of collagen are highly biocompatible materials that can be molded into a range of shapes suitable for cardiac patch applications. The addition of mechanically reinforcing materials, carbon nanotubes, at subtoxic levels allows for the collagen hydrogels to be strengthened, up to a toughness of 30 J m-1 and a two to threefold improvement in Youngs' modulus, thus improving their viability as cardiac patch materials. The addition of carbon nanotubes is shown to be both nontoxic to stem cells, and when using single-walled carbon nanotubes, supportive of live, beating cardiac cells, providing a pathway for the further development of a cardiac patch.