Tum-on sensor

Smith RC, Tennyson AG, Lim MH, Lippard SJ (2005) Conjugated polymer-based fluorescence tum-on sensor for nitric oxide. Org Lett 7 3573-3575... 

McQuade DT, Hegedus AH, Swager TM (2000) Signal amplification of a tum-on sensor harvesting the light captured by a conjugated polymer. J Am Chem Soc 122 12389-12390... 

Li Y, Zhang S, Song D (2013) A luminescent metal-organic framework as a tum-on sensor for DMF vapor. Angew Chem Int Ed 52 710-713... 

Huang CC, Chang HT (2006) Selective gold-nanoparticle-based tum-on fluorescent sensors for detection of mercury(II) in aqueous solution. Anal Chem 78 8332-8338... 

Keywords Conjugated polymer Fluorescent sensor FRET Turn-off Tum-on... 

Ma G, Muller AM, Bardeen CJ, Cheng Q (2006) Self-assembly combined with photopolymerization for the fabrication of fluorescence tum-on vesicle sensors with reversible on-off switching properties. Adv Mater 18 55-60... 

Mercury(ll) reacts with dithizone to form the mixed N,S-donor complex mercury dithizonate (25). This complex has interesting photochromic properties (see Photochromism). For example, its solutions in a variety of organic solvents are orange in weak illumination, but they turn dark blue in sunlight or intense artificial light. The water-soluble, tum-on florescein-based sensor (26) that exhibits environmentally relevant selectivity and sensitivity for Hg was recently reported. ... 

In the initial screen, one compound (given the name GTP Green, Fig. 6-8) displayed fluorescence enhancement ( tum-on ) upon GTP binding and was favorably photostable compared to other candidates [76], Prior to the discovery of GTP Green, the only other GTP sensor (rationally designed) was a turn-off sensor [78], GTP Green displayed a red-shifted 80-fold fluorescence enhancement (Tern = 540 nm) in the presence of GTP and only < two-fold increases with the other nucleotide triphosphates ATP, TTP, and UTP. This compound was also found to be selective for GTP over the mono- and diphosphate homologs. 

Even for a very precise IMU the azimuth error caused by the gyro drift increases to a considerable extent. Of course we have to remark that in high precision applications the inertial sensors are very carefully calibrated, and the sensor output is compensated for the main error sources. Thus in the alignment only the error caused by tum-on repeatability of the sensor biases has to be considered. 

Hg2+) has been shown to coordinate to DNA duplexes that feature thymine-thymine (T-T) base pair mismatches. The general concept used in this approach is that the tum-on reaction of a haiipin probe via coordination of Hg2+ by the T-T base pair results in a substantial increase in the SPR response, followed by specific hybridization with a gold nanoparticle probe to amplify the sensor performance. 

Figure 7.31a shows the response of a polyaniline sensor to 378 ppm ammonia vapor in a headspace system. The sensor response is clearly reversible even after being exposed for more than 1 h. The tum-on (Figure 7.31c) and turn-off (Figure 7.31d) of the sensor take place within 10 s as revealed by the first derivative plot of the response (Figure 7.31b through Figure 7.3Id). The reversibility of the ammonia sensor is observed directly by changes in the color of polyaniline nanofiber films on exposure to ammonia. A green polyanOine nanoliber film is exposed to ammonia vapor ( --76%)...

Fluorescent chemosensors for the detection of heavy metal ions by a simple fluorescence tum-on (off-on) or quenching (on-ofi) are a fundamental tool for a rapid and nondestructive analysis of biochemical and environmental matrices (2007CSR993). A hot topic is the des p of selective sensors for Hg, one of the most hazardous pollutants of the environment. In this context, a new tren-based starburst molecule containing fluorinated 1,2,4-oxadiazoles as fluorophores has been synthesized and its sensing behavior towards several metal cations has been investigated by UV/Vis, fluorescence. 

FIGURE 13.6 Mechanism of the tum-on (top) and txim-off bottom) proteases sensors based on quenching of a conjugated poiyeiectroiyte (dotted line) by a quencher (black circlej-labeled peptide (black line). 

Huang CC, Chang HT (2006) Selective gold-nanoparticle-based tum-on fluorescent sensors for detection of mercury(II) in aqueous solution. Anal Chem 78 8332-8338 He X, Liu H, Li Y et al (2005) Gold nanoparticle-based fluorometric and colorimetric sensing of copper(II) ions. Adv Mater 17 2811-2815... 

Do F4 transitions. Remarkably, the MOF shows an eightfold enhancement of the luminescence intensity in presence of DMF vapors. The luminescent signal becomes weaker once the MOF is exposed to water vapors. Thus, the authors demonstrated sensor response of the MOF to DMF and water vapors. The vapors of DMF and water were introduced into the sensor cell in an alternating manner, and the luminescent intensity was monitored continuously. The tum-on and turn-off switching of luminescence was achieved within 10-20 s. 

The basic idea behind the AV analysis is to take a long sequence of data (A samples) with the sensor being static (no motion) and integrating the output of the inertial sensor to get 6 values with correspondingly removed initial tum-on biases [12] with the experimental data usually plotted as a log-log curve. 

Wang, Z. Heon Lee, J. Lu, Y. Highly sensitive "tum-on" fluorescent sensor for Hg + in aqueous solution based on structure-switching DNA. Chem. Commun. 2008, 6005-6007. 

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