Interest in biosensors based on field-effect transistors (FETs), where an electrically operated gate controls the flow of charge through a semiconducting channel, is driven by the prospect of integrating biodetection capabilities into existing semiconductor technology. In a number of proposed FET biosensors, surface interactions with biomolecules in solution affect the operation of the gate or the channel. However, these devices often have limited sensitivity. We show here that a FET biosensor with a vertical gap is sensitive to the specific binding of streptavidin to biotin. The binding of the streptavidin changes the dielectric constant (and capacitance) of the gate, resulting in a large shift in the threshold voltage for operating the FET. The vertical gap is fabricated using simple thin-film deposition and wet-etching techniques. This may be an advantage over planar nanogap FETs, which require lithographic processing. We believe that the dielectric-modulated FET (DMFET) provides a useful approach towards biomolecular detection that could be extended to a number of other systems.

A label‐free biosensor based on a nanogap‐embedded field‐effect transistor is demonstrated. When biomolecules fill the molecular‐sized nanogap, the transistor parameters are remarkably changed by the gate dielectric constant. The transistor detects specific binding between the avian influenza antibody and an antigen with the silica‐binding protein.

This article describes the controllable construction of a layered superstructure of gold nanooctahedra via a molecularly mediated assembly and their electrochemical application as a host matrix toward the oxidation of glucose. The layered superstructures of the Au nanooctahedra were confirmed with atomic force microscopy, X-ray electron spectroscopy, and cyclic voltammograms. The effects of the interface of gold spherical nanoparticles and the different layered interface of gold nanooctahedra on the electrochemical responses to Fe(CN)6 3- and glucose were investigated in detail. The glucose biosensor, which uses the Au nanooctahedra layer structure as a matrix, shows excellent electrocatalytic activities, such as a high level of sensitivity, a fast response, and a wide response range.

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A thermally actuated organic display device using UV-sensitive polydiacetylene (PDA)-polyvinyl alcohol (PVA) composite film with self aligned patterns is presented. A novel technique that patterns UV-sensitive organic films on a transparent substrate using a chip-embedded photomask is demonstrated. In contrast to related works regarding PDA and its composites, the current investigation represents the first attempt to realize a PDA derivative film for a thermal-display. Micro-pixels ranging from 200µm to 700µm size were fabricated on a glass substrate. The transition tones of the blue, red and yellow micro-pixels were successfully tuned with embedded micro-heaters under the PDA-PVA layer using both low-temperature (75°C) and high-temperature (180°C) activation processes. The retention time was measured and found to be less than a few hundred milliseconds.