Solid state NMR of 17O enriched cholesterol in bilayers reveals the chemical shift depends on extent of hydrogen bonding.

Time-gated interrogation of phosphorescent labels allows high sensitivity detection of analytes by excluding background fluorescence and stray excitation light. Here we report a method for preparing phosphorescent polymer nanospheres with optical properties specifically designed to enable time-gated detection with both organic and inorganic light-emitting diodes and photodiodes. The nanospheres were formed by co-precipitating the phosphorescent dye ruthenium diphenyl phenanthroline with the amphiphilic statistical co-polymer poly(styrene-co-maleic acid). To minimize aggregation and ensure effective encapsulation against water and oxygen ingress, the polymer chains were cross-linked with the small-molecule crosslinker bisphenol A diglycidyl ether, resulting in near-monodisperse nanospheres with excellent resilience against aggregation and quenching. The nanospheres exhibited long phosphorescence lifetimes of 5.3 AE 0.1 ms, high photoluminescence quantum efficiencies of 33 AE 5%, and excellent stability under UV irradiation. Using a blue light-emitting diode as a light-source and a silicon photodiode as a detector, a low detection limit of 4 mg ml À1 was achieved. The suitability of the nanospheres for bioanalysis was demonstrated by surface functionalising them with biotin to yield a simple biolabel for streptavidin.

Teaching practical laboratory skills is a key component of preparing undergraduate students for future careers in chemistry and elsewhere. In this paper, we present our new strategy to teach practical skills to undergraduate chemistry students. We report a Skills Inventory, a list of the suggested practical skills a graduate chemist should possess; this list was compiled by chemists across the UK. In our new practical course we begin by decoupling the practical skill from the theoretical background, compelling students to first master the basic processes needed to carry out a specific technique. In what we have termed a ‘spiral curriculum’ approach, skills are revisited on multiple occasions, with increasing complexity and greater emphasis on underlying theory. The new course makes links across traditional subdisciplines of chemistry to avoid compartmentalisation of ideas.

The interactions between small molecules and keratins are poorly understood. In this paper, a nuclear magnetic resonance method is presented to measure changes in the 1 H T 1 relaxation times of small molecules in human hair keratin to quantify their interaction with the fibre. Two populations of small-molecule compounds were identified with distinct relaxation times, demonstrating the partitioning of the compounds into different keratin environments. The changes in relaxation time for solvent in hair compared with bulk solvent were shown to be related to the molecular weight (MW) and the partition coefficient, LogP, of the solvent investigated. Compounds with low MWs and high hydrophilicities had greater reductions in their T 1 relaxation times and therefore experienced increased interactions with the hair fibre. The relative population sizes were also calculated. This is a significant step towards modelling the behaviour of small molecules in keratinous materials and other large insoluble fibrous proteins.