We report the electrochemical detection of the redox active cardiac biomarker myoglobin (Mb) using aptamer-functionalised black phosphorus nanostructured electrodes by measuring direct electron transfer. The as-synthesised few layer black phosphorus nanosheets have been functionalised with poly-L-lysine (PLL) to facilitate binding with generated anti-Mb DNA aptamers on nanostructured electrodes. This aptasensor platform has a record-low detection limit (~0.524 pg mL-1) and sensitivity (36 µA pg-1 mL cm-2) towards Mb with a dynamic response range from 1 pg mL-1 to 16 µg mL-1 for Mb in serum samples. This strategy opens up avenues to bedside technologies for multiplexed diagnosis of cardiovascular diseases in complex human samples.

Transition metal oxides show great promise as Earth-abundant catalysts for the oxygen evolution reaction in electrochemical water splitting. However, progress in the development of highly active oxide nanostructures is hampered by a lack of knowledge of the location and nature of the active sites. Here we show, through atom-resolved scanning tunnelling microscopy, X-ray spectroscopy and computational modelling, how hydroxyls form from water dissociation at under coordinated cobalt edge sites of cobalt oxide nanoislands. Surprisingly, we find that an additional water molecule acts to promote all the elementary steps of the dissociation process and subsequent hydrogen migration, revealing the important assisting role of a water molecule in its own dissociation process on a metal oxide. Inspired by the experimental findings, we theoretically model the oxygen evolution reaction activity of cobalt oxide nanoislands and show that the nanoparticle metal edges also display favourable adsorption energetics for water oxidation under electrochemical conditions.

Air-stable caesium tin iodide double perovskite (Cs₂SnI₆) thin films have been fabricatedviaaerosol-assisted chemical vapour deposition (AACVD).