A Janus three-dimensional DNA nanomachine was constructed for the simultaneous and sensitive fluorescent detection and imaging of dual microRNAs in the cancer cells.

Freestanding bipolar membranes (BPMs) with an extended-area water splitting junction were fabricated utilizing electrospinning. The junction layer was composed of a mixed fiber mat that was made by concurrently electrospinning sulfonated poly­(ether ether ketone) (SPEEK) and quaternized poly­(phenylene oxide) (QPPO), with water splitting catalyst nanoparticles intermittently deposited between the fibers. The mat was sandwiched between solution cast SPEEK and QPPO films and hot-pressed to form a dense trilayer BPM with an extended-area junction of finite thickness, composed of QPPO nanofibers embedded in a SPEEK matrix with the catalyst nanoparticles interspaced between the two polymers. The composition, ion-exchange capacity, and catalyst type/loading in the junction were varied, and the water splitting characteristics of the membranes were assessed. The best BPMs fabricated in this work employed a graphene oxide catalyst and exhibited a low trans-membrane voltage drop of about 0.82 V at 1000 mA/cm2 in water splitting experiments with 0.5 M Na2SO4 and stable water splitting operation for 60 h at 800 mA/cm2.

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Carbon dots/Fe3O4 hybrid nanofibers as efficient peroxidase mimics for sensitive detection of H2O2 and ascorbic acid have been developed.