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MicroRNAs (miRNAs) are emerging new biomarkers for many human diseases. To fully employ miRNAs as biomarkers for clinical diagnosis, it is most desirable to accurately determine the expression patterns of miRNAs. The optimum miRNA profiling method would feature 1) highest sensitivity with a wide dynamic range for accurate expression patterns, 2) supreme specificity to discriminate single nucleotide polymorphisms (SNPs), and 3) simple sensing processes to minimize measurement variation. Here, an ultra-specific detection method of miRNAs with zeptomole sensitivity is reported by applying bi-temperature hybridizations on single-crystalline plasmonic nanowire interstice (PNI) sensors. This method shows near-perfect accuracy of SNPs and a very low detection limit of 100 am (50 zeptomole) without any amplification or labeling steps. Furthermore, multiplex sensing capability and wide dynamic ranges (100 am-100 pm) of this method allows reliable observation of the expression patterns of miRNAs extracted from human tissues. The PNI sensor offers combination of ultra-specificity and zeptomole sensitivity while requiring two steps of hybridization between short oligonucleotides, which could present the best set of features for optimum miRNA sensing method., (© 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.)

A sensor detecting telomerase activity by surface enhanced Raman scattering is described by Taejooon Kang, Bongsoo Kim, and co‐workers in article number 1701832. Through an optimized nanogap‐rich gold nanowire, the sensor successfully detects telomerase activity in gastric cancer and breast cancer tissues, demonstrating its applicability for cancer diagnosis. [ABSTRACT FROM AUTHOR]

We demonstrate the efficient integration of an electricallydrivennanowire (NW) light source with a double-strip plasmonic waveguide.A top-down-fabricated GaAs NW light-emitting diode (LED) is placedbetween two straight gold strip waveguides with the gap distance decreasingto 30 nm at the end of the waveguide and operated by current injectionthrough the p-contact electrode acting as a plasmonic waveguide. Measurementsof polarization-resolved images and spectra show that the light emissionfrom the NW LED was coupled to a plasmonic waveguide mode, propagatedthrough the waveguide, and was focused onto a subwavelength-sizedspot of surface plasmon polaritons at the tapered end of the waveguide.Numerical simulation agreed well with these experimental results,confirming that a symmetric plasmonic waveguide mode was excited onthe top surface of the waveguide. Our demonstration of a plasmonicwaveguide coupled to an electrically driven NW LED represents importantprogress toward further miniaturization and practical implementationof ultracompact photonic integrated circuits. [ABSTRACT FROM AUTHOR]

Optical antennas interface an object with optical radiationandboost the absorption and emission of light by the objects throughthe antenna modes. It has been much desired to enhance both excitationand emission processes of the quantum emitters as well as to interfacemultiwavelength channels for many nano-optical applications. Herewe report the experimental implementation of an optical antenna operatingin the full visible range via surface plasmon currents induced ina defect-free single-crystalline Ag nanowire (NW). With its atomicallyflat surface, the long Ag NW reliably establishes multiple plasmonicresonances and produces a unique rainbow antenna radiation in theFresnel region. Detailed antenna radiation properties, such as radiatingnear-field patterns and polarization states, were experimentally examinedand precisely analyzed by numerical simulations and antenna theory.The multiresonant Ag NW nanoantenna will find superb applicationsin nano-optical spectroscopy, high-resolution nanoimaging, photovoltaics,and nonlinear signal conversion. [ABSTRACT FROM AUTHOR]