Saliva-based sensors

Carbon Nanotubes Based Sensors for Biomonitoring ChE Activity in Saliva... 

FRET to occur, and thus no FI emission is observed. The specificity of this assay was also examined for mixed samples. The mixed lysozyme samples were prepared in fetal bovine serum (FBS), human saliva and human urine. It was found that FAM emission was still visible upon addition of each mixed sample, implying that this assay has a great potential for the detection of real biological samples. This study illuminates that introduction of specific aptamer/protein interaction as the recognition event, and utilization of FRET as the signal transduction channel, is an effective way to develop CPE-based protein sensors with good specificity. 

The fluid nature of PTC cocktails allows them to conform to the shape of a surface. Consequently, on evaporation of the tetrahydro-furan the PTC sensor film is left as a particular contour. This has allowed improved designs of ISEs, e.g., coated wires/epoxy, tubular flow-through, micro and all solid-state epoxy models. Thus, a lithiun sensor cast on top of a small epoxy base in a flow injection system is suitable for the assay of lithium in the saliva of manic depressive patients (Beswick,C.W., MDody,G.J., Thomas,J.D.R., diversity of Wales College of Cardiff, unpublished data). 

We developed a CNT-based electrochemical sensor in conjunction with a flow-injection system to measure ChE activity in sahva. The assay of enzyme activity in saliva is based on excellent electrocatalytic properties of CNTs, which make enzymatic products detectable at a low potential with an extremely high sensitivity. The amount of enzymatic product generated from ChEs depends on enzyme activity therefore, by detecting the electroactive enzymatic product, this CNT-based electrochemical sensor can measure the ChE aetivity in saliva. 

The CNT-based electrochemical sensor was used for the measurement of ChE enzyme activity in saliva samples. Paraoxon and the 10-fold diluted naive rat saliva sample were chosen for this study. The inhibition of ChE enzyme activity (with different concentrations of paraoxon) over an increasing incubation time is shown in Figure 9. It can be seen from this Figureure that the enzyme lost almost 97% activity after 0.5 h incubation with 7.0 nM paraoxon, and 80% after 0.5 h incubation with 0.7 nM paraoxon. Thereafter, the enzyme activity corresponding to 0.7 nM paraoxon continues to decrease through 2.0 h post-treatment, while the activity that corresponds to 7.0 nM paraoxon was nearly completely inhibited within 0.5 h This demonstrates that the... 

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