Pneumatically actuated, non-elastomeric membrane valves fabricated from polymerized polyethylene glycol diacrylate (poly-PEGDA) have been characterized for temporal response, valve closure, and long-term durability. A ~100 ms valve opening time and a ~20 ms closure time offer valve operation as fast as 8 Hz with potential for further improvement. Comparison of circular and rectangular valve geometries indicates that the surface area for membrane interaction in the valve region is important for valve performance. After initial fabrication, the fluid pressure required to open a closed circular valve is ~50 kPa higher than the control pressure holding the valve closed. However, after ~1000 actuations to reconfigure polymer chains and increase elasticity in the membrane, the fluid pressure required to open a valve becomes the same as the control pressure holding the valve closed. After these initial conditioning actuations, poly-PEGDA valves show considerable robustness with no change in effective operation after 115,000 actuations. Such valves constructed from non-adsorptive poly-PEGDA could also find use as pumps, for application in small volume assays interfaced with biosensors or impedance detection, for example.

We investigate the performance and limitations of silicon microcantilever arrays as biosensors in which receptor molecules are directly tethered to the native oxide without an intermediate metal adhesion layer such as gold. We use our recently developed in-plane photonic microcantilever (PMCL) readout method to simultaneously measure deflection of individual microcantilevers in a 16-PMCL array integrated with polydimethylsiloxane microfluidics. We demonstrate label-free biosensing of streptavidin using biotin that has been immobilized to only the top side of a subset of PMCLs within the array. The maximum surface stress that we measure is rather small (6 mN/m) for relatively high streptavidin concentration (4.7 µM). We attribute this result to lack of a metal adhesion layer, which eliminates strong surface stress generation from change in metal electronic charge density upon uptake of streptavidin by surfacebound biotin.

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The HIgh-Resolution Mid-infrarEd Spectrometer (HIRMES) is the 3 rd Generation Instrument for the Stratospheric Observatory For Infrared Astronomy (SOFIA), currently in development at the NASA Goddard Space Flight Center (GSFC), and due for commissioning in 2019. By combining direct-detection Transition Edge Sensor (TES) bolometer arrays, grating-dispersive spectroscopy, and a host of Fabry-Perot tunable filters, HIRMES will provide the ability for High Resolution (R∼100,000), Mid-Resolution (R∼10,000), and Low-Resolution (R∼600) slit-spectroscopy, and 2D Spectral Imaging (R∼2000 at selected wavelengths) over the 25 -122 μm mid-far infrared waveband. The driving science application is the evolution of proto-planetary systems via measurements of water-vapor, water-ice, deuterated hydrogen (HD), and neutral oxygen lines. However, HIRMES has been designed to be as flexible as possible to cover a wide range of science cases that fall within its phase-space, all whilst reaching sensitivities and observing powers not yet seen thus far on SOFIA, providing unique observing capabilities which will remain unmatched for decades.