Exosomes, which are membranous nanovesicles, are actively released by cells and have been attributed to roles in cell-cell communication, cancer metastasis, and early disease diagnostics. The small size (30–100 nm) along with low refractive index contrast of exosomes makes direct characterization and phenotypical classification very difficult. In this work we present a method based on Single Particle Interferometric Reflectance Imaging Sensor (SP-IRIS) that allows multiplexed phenotyping and digital counting of various populations of individual exosomes (>50 nm) captured on a microarray-based solid phase chip. We demonstrate these characterization concepts using purified exosomes from a HEK 293 cell culture. As a demonstration of clinical utility, we characterize exosomes directly from human cerebrospinal fluid (hCSF). Our interferometric imaging method could capture, from a very small hCSF volume (20 uL), nanoparticles that have a size compatible with exosomes, using antibodies directed against tetraspanins. With this unprecedented capability, we foresee revolutionary implications in the clinical field with improvements in diagnosis and stratification of patients affected by different disorders.

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High formation yield and a meaningful cooled fraction of positronium below room temperature were obtained by implanting positrons in a silicon target in which well-controlled oxidized nanochannels (5-8 nm in diameter) perpendicular to the surface were produced. We show that by implanting positrons at 7 keV in the target held at 150 K, about 27% of positrons form positronium that escapes into the vacuum. Around 9% of the escaped positronium is cooled by collision with the walls of nanochannels and is emitted with a Maxwellian beam at 150 K. Because positronium quantum confinement limits the minimum achievable positronium energy, the tuning of the nanochannel's size is crucial for obtaining positronium gases in vacuum at very low temperature.

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The authors present a technique that allows to modify the local characteristics of two-dimensional photonic crystals by controlled microinfiltration of liquids. They demonstrate experimentally that by addressing and infiltrating each pore with a simple liquid, e.g., water, it is possible to write pixel by pixel optical devices of any geometry and shape. Calculations confirm that the obtained structures indeed constitute the desired resonators and waveguide structures.

In this letter, we report the formation of bulk samples of silica-based glass containing Si nanocrystals (Si-ncs) by pyrolysis of a preceramic precursor. The starting precursor is a sol–gel-derived polysiloxane containing only Si–H groups which leads, after annealing in a controlled atmosphere in the range 1000–1200 °C, to the precipitation of Si-ncs. Characterization of the nanostructure was performed by x-ray diffraction and Raman scattering analyses. Room-temperature luminescence experiments show the interesting optical properties of the Si-ncs/SiO2 material.

Nanostructuring silicon is an effective way to turn silicon into a photonic material.In fact, low-dimensional silicon shows light amplification characteristics, non-linear optical effects, photon confinement in both one and two dimensions, photon trapping with evidence of light localization, and gassensing properties.

Abstract. We present two transfer bonding schemes for incorporating fragile nanoporous inorganic membranes into microdevices. Such membranes are finding increasing use in microfluidics, due to their precisely controllable nanostructure. Both schemes rely on a novel dual-cure dry adhesive bonding method, enabled by a new polymer formulation: OSTE(+), which can form bonds at room temperature. OSTE(+) is a novel dual-cure ternary monomer system containing epoxy. After the first cure, the OSTE(+) is soft and suitable for bonding, while during the second cure it stiffens and obtains a Young's modulus of 1.2 GPa. The ability of the epoxy to react with almost any dry surface provides a very versatile fabrication method. We demonstrate the transfer bonding of porous silicon and porous alumina membranes to polymeric microfluidic chips molded into OSTE(+), and of porous alumina membranes to microstructured silicon wafers, by using the OSTE(+) as a thin bonding layer. We discuss the OSTE(+) dual-cure mechanism, describe the device fabrication, and evaluate the bond strength and membrane flow properties after bonding. The membranes bonded to OSTE(+) chips delaminate at 520 kPa, and the membranes bonded to silicon delaminate at 750 kPa, well above typical maximum pressures applied to microfluidic circuits. Furthermore, no change in membrane flow resistance was observed after bonding. Dry adhesive bonding of nanoporous inorganic membranes2