Autonomous reagent-based microfluidic pH sensor platform

Sansalvador, Isabel M. Perez de Vargas; Fay, Cormac; Cleary, John; Nightingale, Adrian M.; Mowlem, Matthew C.; Diamond, Dermot

doi:10.1016/j.snb.2015.11.057

Cited by 38 publications

(14 citation statements)

References 26 publications

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“…Possible platforms include tethered and submersible probes, and onboard-ship analysis systems, for oceanic sampling of various analytes. These include phosphorus and phosphates (Bowden and Diamond 2003 ; Legiret et al 2013 ), nitrites and nitrates (Beaton et al 2012 ; Czugala et al 2013 ), ammonium ion (Plant et al 2009 ), manganese (Provin et al 2013 ), ocean acidification via pH (De Vargas Sansalvador et al 2016 ), and total dissolved inorganic carbon (Millero 2007 ).…”

Section: Introductionmentioning

confidence: 99%

Microfluidic ratio metering devices fabricated in PMMA by CO2 laser

Tweedie

Maguire

2020

Microsyst Technol

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We describe microfluidic fabrication results achieved using a 10.6 μm CO2 engraving laser on cast PMMA, in both raster and vector mode, with a 1.5″ lens and a High Power Density Focussing Optics lens. Raster written channels show a flatter base and are more U-shaped, while vector written channels are V shaped. Cross-sectional images, and, where possible, stylus profilometry results are presented. The sides of V-grooves become increasing steep with laser power, but broader shallower channels may be produced in vector mode by laser defocus, as illustrated. Smoothing of raster engraved channels by heated IPA etch, and transparency enhancement by CHCl3 vapour treatment are briefly discussed. An asymmetric Y meter is discussed as one method of diluting acid into seawater for dissolved CO2 analysis. Alternatively, microfluidic snake channel restrictors of different lengths in 2 channels may achieve the same result. Samples are fabricated with bases bonded by CHCl3 vapour treatment, and the devices are flow tested with either dilute food dye or DI water. Microfluidics fabricated in this manner have applications in ocean sensing of dissolved CO2 and other analytes, as well as broader sensing measurements, including biomedical sensors.

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Section: Introductionmentioning

confidence: 99%

Microfluidic ratio metering devices fabricated in PMMA by CO2 laser

Tweedie

Maguire

2020

Microsyst Technol

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“…In the field of environmental monitoring there is a special need for distributed sensors to cover large areas [5][6][7], either as distributed sensors or sensors spread out in numerous locations in for example forests, lakes or landfills. This makes pH responsive coatings that are compatible with the optical or printed sensor technology particularly interesting.…”

Section: Introductionmentioning

confidence: 99%

Synthesis, Curing Behavior and Swell Tests of pH-Responsive Coatings from Acryl-Terminated Oligo(β-Amino Esters)

et al. 2018

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Abstract:The ability of acryl-terminated oligo(β-amino esters) (AOBAE) to be coated on fibers and printed electronics without solvents and to be cross-linked to a pH-responsive coatings, makes AOBAE-based coatings a potential type of pH-sensor coating. However, there are currently no reports of AOBAEs used as a pH-responsive coating material in sensor applications. Here we present an investigation of the synthesis, curing behavior and swell tests of AOBAEs. AOBAEs were synthesized from reacting an excess of asymmetric diacrylates with piperazine without the use of any solvents. They were then cross-linked to an insoluble network by UV-curing. Nuclear magnetic resonance (NMR) and Fourier transform infrared (FTIR) spectroscopy were used to characterize the AOBAEs. NMR was used to clarify the irregular structure of the AOBAE. FTIR was used to monitor the effects of UV-curing dose and air exposure on monomer conversion during curing. An interferometric technique was used to monitor the swelling behavior of the coating in response to pH variations. Swell experiments showed that the AOBAE also responded to pH variations after polymerization. Therefore, AOBAE is an interesting class of material with potential use as a pH responsive coating in optical-and printed electronics pH-sensors applications.

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“…Besides, better interface quality with much lower dislocation density can be realized with reduced interfacial stress when the In composition is at 17.3% (lattice matching with GaN) [13]. According to these advantages, the excellent performances of devices of the AlInN/GaN heterostructure have been reported over the past few decades [14,15,16,17,18]. However, only a few works on ion sensors are based on the AlInN/GaN heterostructure [19,20,21,22].…”

Section: Introductionmentioning

confidence: 99%

High Sensitive pH Sensor Based on AlInN/GaN Heterostructure Transistor

Yan

Son

Dai

et al. 2018

Sensors

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The AlInN/GaN high-electron-mobility-transistor (HEMT) indicates better performances compared with the traditional AlGaN/GaN HEMTs. The present work investigated the pH sensor functionality of an analogous HEMT AlInN/GaN device with an open gate. It was shown that the Al0.83In0.17N/GaN device demonstrates excellent pH sense functionality in aqueous solutions, exhibiting higher sensitivity (−30.83 μA/pH for AlInN/GaN and −4.6 μA/pH for AlGaN/GaN) and a faster response time, lower degradation and good stability with respect to the AlGaN/GaN device, which is attributed to higher two-dimensional electron gas (2DEG) density and a thinner barrier layer in Al0.83In0.17N/GaN owning to lattice matching. On the other hand, the open gate geometry was found to affect the pH sensitivity obviously. Properly increasing the width and shortening the length of the open gate area could enhance the sensitivity. However, when the open gate width is too larger or too small, the pH sensitivity would be suppressed conversely. Designing an optimal ratio of the width to the length is important for achieving high sensitivity. This work suggests that the AlInN/GaN-based 2DEG carrier modulated devices would be good candidates for high-performance pH sensors and other related applications.

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Autonomous reagent-based microfluidic pH sensor platform

Cited by 38 publications

References 26 publications

Microfluidic ratio metering devices fabricated in PMMA by CO2 laser

Microfluidic ratio metering devices fabricated in PMMA by CO2 laser

Synthesis, Curing Behavior and Swell Tests of pH-Responsive Coatings from Acryl-Terminated Oligo(β-Amino Esters)

High Sensitive pH Sensor Based on AlInN/GaN Heterostructure Transistor

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