We report the electrochemical detection of the redox active cardiac biomarker myoglobin (Mb) using aptamer-functionalized black phosphorus nanostructured electrodes by measuring direct electron transfer. The as-synthesized few-layer black phosphorus nanosheets have been functionalized 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)) toward 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.
Lead sulfide has been grown from single molecular precursors within a polymer matrix to form networks of PbS nanocrystals. These materials are model systems for the processing of polymer-nanoparticle layers for flexible hybrid photovoltaic devices. Processing is achieved by spin coating a solution containing the precursor and polymer on to a substrate, followed by heating of the film to decompose the precursor. The effect of precursor chemistry has been explored using: lead(II) dithiocarbamates, their 1,10-phen adducts, and lead(II) xanthates with different alkyl chain lengths (butyl, hexyl, and octyl). The xanthates were found to be more promising precursors giving control over nanocrystal size and shape on variation of the alkyl chain length. The lead(II) octyl xanthate complex causes anisotropic growth, forming PbS nanowires within the polymer matrix.
Transition metal chalcogenides are an important family of materials that have received significant interest in recent years as they have the potential for diverse applications ranging from use in electronics to industrial lubricants.
A series of lead(ii) alkylxanthates, [Pb(SCOR)] (R = ethyl (1), n-propyl (2), n-butyl (3), n-hexyl (4) or n-octyl (5)) have been prepared and explored as single source precursors for use in melt reactions to form lead sulfide. X-ray single crystal structures of (2), (3) and (4) were used along with previously reported structures to investigate the influence of structure and chain length on the materials produced. The complexes were decomposed at 150, 175 or 200 °C forming PbS nanocrystals as confirmed by XRD and TEM. Analysis by SEM shows that the choice of precursor had an influence on nanocrystal size with longer alkyl chains resulting in smaller cubic nanocrystals. In addition to cubes, anisotropic growth was observed from decomposition of compound (5).
The stability of few-layer black phosphorus has been studied in aqueous media using a range of spectroscopic techniques. The material is meta-stable, degrading over time mainly to phosphoric acids.
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