Decyl Methacrylate-Based Microspot Optodes

Abstract

Optode sensing membranes employing decyl methacrylate cross-linked with 1,6-hexanediol dimethacrylate as the polymer support were fabricated by a direct microspotting method on several surfaces. Photopolymerization was used to attach the microspots to the substrate. Using this method, diameters in the micrometer domain were obtained. Silanized glass, poly(methyl methacrylate) (PMMA), polycarbonate, and poly(dimethylsiloxane) were tested as possible substrates. Both polypropylene tips and the steel tips of drafting pens were used for spotting. It was determined that both silanized glass and PMMA gave working optodes, but the ones on PMMA did not fit the theoretical model. Diameters of 994 +/- 80 and 1279 +/- 85 microm were obtained on silanized glass and PMMA, respectively, using the polypropylene tips for spotting. Different size optodes were fabricated using 0.35- and 0.50-mm steel drafting pen tips. The 0.35-mm tips produced diameters of 895 +/- 26 and 688 +/- 54 microm on silanized glass and PMMA, respectively, and the 0.50-mm tips produced diameters of 1274 +/- 94 microm on silanized glass and 839 +/- 28 microm on PMMA. Thus, the microspot size can be controlled based on the hydrophobicity of the surface and the size of the tip used for spotting. Calibration plots of potassium optode microspots indicated that miniaturization does not alter response characteristics, such as selectivity, response time, and dynamic range, of the optodes.

K+-selective nanospheres: maximising response range and minimising response time

“…One approach to overcome this was the fabrication of plasticizer-free polymers, such as methacrylic and methacrylicacrylic copolymers, 15,16,[25][26][27][28] which have mostly been evaluated previously in ion-selective electrodes (ISEs). These polymers have been shown to be potential matrices for both chemical sensors [29][30][31][32][33][34][35] and biosensors.…”

Lab-on-a-CD: A Fully Integrated Molecular Diagnostic System

“…90 Electroosmotic mixing has not been implemented on a CD due to its dependence on the sample's pH and ionic strength. 91 Mixing using piezoelectric actuation also has not yet been implemented on a microfluidic disc but could be developed in the future for suitable platforms. Active mixing using magnetic beads is simple and effective, and has been demonstrated on a microfluidic disc by Grumman et al 92 In this technique, termed batch-mode mixing, a series of permanent magnets were placed at alternating radial distances underneath the mixing chamber, while magnetic microbeads were placed inside the mixing chamber.…”

Microfluidic ion-sensing devices

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