Modular Aptamer Switches for the Continuous Optical Detection of Small-Molecule Analytes in Complex Media.

Aptamers are a promising class of affinity reagents because signal transduction mechanisms can be built into the reagent, so that they can directly produce a physically measurable output signal upon target binding. However, endowing the signal transduction functionality into an aptamer remains a trial-and-error process that can compromise its affinity or specificity and typically requires knowledge of the ligand binding domain or its structure. In this work, a design architecture that can convert an existing aptamer into a "reversible aptamer switch" whose kinetic and thermodynamic properties can be tuned without a priori knowledge of the ligand binding domain or its structure is described.

Compact diaphragm-based optical accelerometers with µg/√Hz resolution.

A compact fiber accelerometer that meets the resolution requirement for aircraft navigation is reported. It detects extremely weak acceleration-induced vibrations of a spring-loaded diaphragm using a two-wave interferometer with a /2 biasing step micro-fabricated on the diaphragm. A single-mode fiber provides a laser beam that interrogates the interferometer.