A portable explosive detector based on fluorescence quenching of pyrene deposited on coloured wax-printed μPADs

Taudte, Regina Verena; Beavis, Alison; Wilson-Wilde, Linzi; Roux, Claude; Doble, Philip; Blanes, Lucas

doi:10.1039/c3lc50609f

Cited by 79 publications

(61 citation statements)

References 45 publications

(71 reference statements)

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“…19 However, the present study focuses more on the vertical spreading of colored wax and the resulting potential for creating hydrophobic barriers in order to realize time-delay channels for lPAD devices. Rectangles of chromatography paper with dimensions of 7 mm Â 3 mm and 7 mm Â 9 mm, respectively, were prepared and printed with yellow, cyan, magenta, and black wax, with concentration gradients ranging from 0% to 100% (see Figs.…”

Section: B Principle Of Colored Wax-printed Timersmentioning

confidence: 99%

“…5,19 In such methods, the wax is first printed on the surface of the paper and is then heated such that it spreads both laterally and vertically. In practice, the vertical spreading of the wax creates hydrophobic barriers which constrain the wicking direction, while the lateral spreading of the wax decreases the sharpness of the channel defined by the barrier and broadens the barrier width.…”

Section: Introductionmentioning

confidence: 99%

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Colored wax-printed timers for two-dimensional and three-dimensional assays on paper-based devices

et al. 2014

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Microfluidic paper-based analytical devices (lPADs) are widely used for performing diagnostic assays. However, in many assays, time-delay valves are required to improve the sensitivity and specificity of the results. Accordingly, this study presents a simple, low-cost method for realizing time-delay valves using a color wax printing process. In the proposed approach, the time-delay effect is controlled through a careful selection of both the color and the saturation of the wax content. The validity of the proposed method is demonstrated by performing nitrite and oxalate assays using both a simple two-dimensional lPAD and a three-dimensional lPAD incorporating a colored wax-printed timer. The experimental results confirm that the flow time can be controlled through an appropriate selection of the color and the wax content. In addition, it is shown that nitrite and oxalate assays can be performed simultaneously on a single device. In general, the results presented in this study show that the proposed lPADs provide a feasible low-cost alternative to conventional methods for performing diagnostic assays. V C 2014 AIP Publishing LLC.

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Section: B Principle Of Colored Wax-printed Timersmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Colored wax-printed timers for two-dimensional and three-dimensional assays on paper-based devices

et al. 2014

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“…The latest developments in miniaturization [1] have demonstrated the enormous potential of microfluidic devices for agricultural [2,3], chemical, biomedical, and forensic applications [4,5]. Among those devices designed for custom analytical and bioanalytical applications, microchip electrophoresis (ME) devices are some of the most important ones [6][7][8].…”

Section: Introductionmentioning

confidence: 99%

Fast and versatile fabrication of PMMA microchip electrophoretic devices by laser engraving

Gabriel,

Coltro,

Garcia

2014

Electrophoresis

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This paper describes the effects of different modes and engraving parameters on the dimensions of microfluidic structures produced in PMMA using laser engraving. The engraving modes included raster and vector while the explored engraving parameters included power, speed, frequency, resolution, line-width and number of passes. Under the optimum conditions, the technique was applied to produce channels suitable for CE separations. Taking advantage of the possibility to cut-through the substrates, the laser was also used to define solution reservoirs (buffer, sample, and waste) and a PDMS-based decoupler. The final device was used to perform the analysis of a model mixture of phenolic compounds within 200 s with baseline resolution.

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“…The recent development of fluorescence quenching-based chemical sensors offers a route towards portable and compact devices [2][3][4].…”

Section: Introductionmentioning

confidence: 99%

Diffusion of nitroaromatic vapours into fluorescent dendrimer films for explosives detection

Ali¹,

Chen²,

Cavaye³

et al. 2015

Sensors and Actuators B: Chemical

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Abstract:Fluorescence-based sensing with organic semiconductors is a powerful method for the detection of a broad range of analytes including explosives, chemical weapons and drugs.Diffusion of an analyte into an organic semiconductor thin film, and its subsequent interaction with the chromophore are key factors that govern the sensing performance of a chemosensor.In this study the diffusion behaviour of an explosive analyte analogue into a sensing film of a conjugated dendrimer was investigated using a quartz crystal microbalance (QCM) and correlated with neutron reflectivity measurements. The mechanistic insights of paranitrotoluene (pNT) sorption in the films of different thicknesses of a first generation dendrimer with fluorenyl surface groups, carbazole dendrons and a spirobifluorene core were studied and interpreted in terms of the underlying kinetics and thermodynamics. Sorption measurements suggest that the process of diffusion of pNT vapour into the dendrimer films is Super Case II, which involves swelling of the film. Swelling of the film was confirmed by neutron reflectometry measurements, which also showed uniform distribution of the pNT molecules throughout the entire film thickness. The activation energy barrier and change in Gibbs free energy in the sorption process were calculated from the QCM responses. The sorption process was found to be thermodynamically (not kinetically) controlled and independent of film thickness. This work sheds insight into the structure-property relationships that govern the performance of organic semiconductor fluorescence-based chemosensors.

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A portable explosive detector based on fluorescence quenching of pyrene deposited on coloured wax-printed μPADs

Cited by 79 publications

References 45 publications

Colored wax-printed timers for two-dimensional and three-dimensional assays on paper-based devices

Colored wax-printed timers for two-dimensional and three-dimensional assays on paper-based devices

Fast and versatile fabrication of PMMA microchip electrophoretic devices by laser engraving

Diffusion of nitroaromatic vapours into fluorescent dendrimer films for explosives detection

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