/pdf/functional-nucleic-acid-sensors-k8tlieshyr.pdf

Functional Nucleic Acid Sensors

In recent years, there has been an increasing interest in the adoption of emerging sensing technologies for instrumentation within a variety of structural systems. Wireless sensors and sensor networks are emerging as sensing paradigms that the structural engineering field has begun to consider as substitutes for traditional tethered monitoring systems. A benefit of wireless structural monitoring systems is that they are inexpensive to install because extensive wiring is no longer required between sensors and the data acquisition system. Researchers are discovering that wireless sensors are an exciting technology that should not be viewed as simply a substitute for traditional tethered monitoring systems. Rather, wireless sensors can play greater roles in the processing of structural response data; this feature can be utilized to screen data for signs of structural damage. Also, wireless sensors have limitations that require novel system architectures and modes of operation. This paper is intended to serve as a summary review of the collective experience the structural engineering community has gained from the use of wireless sensors and sensor networks for monitoring structural performance and health.

http://www-personal.umich.edu/~jerlynch/papers/SVDReview.pdf

A summary review of wireless sensors and sensor networks for structural health monitoring

The advent of negative index materials has spawned extensive research into metamaterials over the past decade. Metamaterials are attractive not only for their exotic electromagnetic properties, but also their promise for applications. A particular branch–the metamaterial perfect absorber (MPA)–has garnered interest due to the fact that it can achieve unity absorptivity of electromagnetic waves. Since its first experimental demonstration in 2008, the MPA has progressed significantly with designs shown across the electromagnetic spectrum, from microwave to optical. In this Progress Report we give an overview of the field and discuss a selection of examples and related applications. The ability of the MPA to exhibit extreme performance flexibility will be discussed and the theory underlying their operation and limitations will be established. Insight is given into what we can expect from this rapidly expanding field and future challenges will be addressed.

https://www.onlinelibrary.wiley.com/doi/pdf/10.1002/adma.201200674

Metamaterial Electromagnetic Wave Absorbers

SELEX--a (r)evolutionary method to generate high-affinity nucleic acid ligands.

Gene silencing by heterochromatin is proposed to occur in part as a result of the ability of heterochromatin protein 1 (HP1) proteins to spread across large regions of the genome, compact the underlying chromatin and recruit diverse ligands. Here we identify a new property of the human HP1α protein: the ability to form phase-separated droplets. While unmodified HP1α is soluble, either phosphorylation of its N-terminal extension or DNA binding promotes the formation of phase-separated droplets. Phosphorylation-driven phase separation can be promoted or reversed by specific HP1α ligands. Known components of heterochromatin such as nucleosomes and DNA preferentially partition into the HP1α droplets, but molecules such as the transcription factor TFIIB show no preference. Using a single-molecule DNA curtain assay, we find that both unmodified and phosphorylated HP1α induce rapid compaction of DNA strands into puncta, although with different characteristics. We show by direct protein delivery into mammalian cells that an HP1α mutant incapable of phase separation in vitro forms smaller and fewer nuclear puncta than phosphorylated HP1α. These findings suggest that heterochromatin-mediated gene silencing may occur in part through sequestration of compacted chromatin in phase-separated HP1 droplets, which are dissolved or formed by specific ligands on the basis of nuclear context.

/pdf/liquid-droplet-formation-by-hp1a-suggests-a-role-for-phase-51h5c1os0q.pdf

Liquid droplet formation by HP1α suggests a role for phase separation in heterochromatin

Integrated-circuit antennas.

Aptamer biosensors have been immobilized on beads, introduced into micromachined chips on the electronic tongue sensor array, and used for the detection and quantitation of proteins. Aptamer chips could detect proteins in both capture and sandwich assay formats. Unlike most protein-based arrays, the aptamer chips could be stripped and reused multiple times. The aptamer chips proved to be useful for screening aptamers from in vitro selection experiments and for sensitively quantitating the biothreat agent ricin.

Aptamer-based sensor arrays for the detection and quantitation of proteins

Multifunctional epidermal sensor systems (ESS) are manufactured with a highly cost and time effective, benchtop, and large-area "cut-and-paste" method. The ESS made out of thin and stretchable metal and conductive polymer ribbons can be noninvasively laminated onto the skin surface to sense electrophysiological signals, skin temperature, skin hydration, and respiratory rate.

“Cut‐and‐Paste” Manufacture of Multiparametric Epidermal Sensor Systems

A micromachined sensor array has been developed for the rapid characterization of multi-component mixtures in aqueous media. The sensor functions in a manner analogous to that of the mammalian tongue, using an array composed of individually immobilized polystyrene-polyethylene glycol composite microspheres selectively arranged in micromachined etch cavities localized o n silicon wafers. Sensing occurs via colorimetric or fluorometric changes to indicator molecules that are covalently bound to amine termination sites on the polymeric microspheres. The hybrid micromachined structure has been interfaced directly to a charged-coupled-device that is used for the simultaneous acquisition of the optical data from the individually addressable `taste bud' elements. With the miniature sensor array, acquisition of data streams composed of red, green, and blue color patterns distinctive for the analytes in the solution are rapidly acquired. The unique combination of carefully chosen reporter molecules with water permeable microspheres allows for the simultaneous detection and quantification of a variety of analytes. The fabrication of the sensor structures and the initial colorimetric and fluorescent responses for pH, Ca+2, Ce+3, and sugar are reported. Interface to microfluidic components should also be possible, producing a complete sampling/sensing system.© (1998) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.

http://weewave.mer.utexas.edu/MED_files/Electreprint/JACS_tongue_lett_7_98.pdf

Solution-based analysis of multiple analytes by a sensor array: toward the development of an electronic tongue

Rules for determining a compact circuit model consisting of four resistors and three inductors to accurately predict the skin effect have been developed. The circuit is easily constructed from the geometry, producing a response that matches exact results over a frequency range from dc to very high frequencies.

Dean P. Neikirk

Papers

Integrated-circuit antennas.

Aptamer-based sensor arrays for the detection and quantitation of proteins

“Cut‐and‐Paste” Manufacture of Multiparametric Epidermal Sensor Systems

Solution-based analysis of multiple analytes by a sensor array: toward the development of an electronic tongue

Compact equivalent circuit model for the skin effect