Photoinduced Electron Transfer Based Ion Sensing within an Optical Fiber

Abstract

We combine suspended-core microstructured optical fibers with the photoinduced electron transfer (PET) effect to demonstrate a new type of fluorescent optical fiber-dip sensing platform for small volume ion detection. A sensor design based on a simple model PET-fluoroionophore system and small core microstructured optical fiber capable of detecting sodium ions is demonstrated. The performance of the dip sensor operating in a high sodium concentration regime (925 ppm Na+) and for lower sodium concentration environments (18.4 ppm Na+) is explored and future approaches to improving the sensor’s signal stability, sensitivity and selectivity are discussed.

Metal Ion Sensing for Biomedical Uses

“…The proof-of-principle of a PET-based optical dip-sensor with an N-phenyl aza-15-crown-5 ether, but lacking the methoxy arm as in 1 has been developed by an Australian team. 41 Early fluorescent PET sensors with crown ethers were designed with an anthracene fluorophore with synthetic simplicity in mind. [42][43][44] Molecule 2 was studied in methanol owing to solubility issues in water and found to have a log b Na 1 of 2.3, a maximum fluorescence of only 0.06 and a switching on factor of 6.…”

Towards microstructured optical fibre sensors: surface analysis of silanised lead silicate glass

“…The measurement method was reported in previous literature. 6 The 30 sensitivity setting used was medium, the resolution for each pixel was 100 μm and the photomultiplier tube (PMT) voltage was 500 V. The average fluorescence intensity per mm 2 of the slides was obtained by measuring 300 data points from three slides per treatment. The measurement error is 1 standard deviation (SD) of 35 300 data points.…”

“…[1][2][3][4][5][6][7][8][9] MOFs can be fabricated from various glass types 25 including silica, tellurite, heavy metal fluoride, bismuth and lead silicate. Non-silica (soft) glasses can be readily fabricated using an extrusion process, which enables the formation of novel optical fibre architectures feasible for sensing applications.…”

“…As compounds 1-3 are fluoroionophores, they show increased emission intensity upon complexation of sodium or other positive 75 ions of similar size. 6,33 As a consequence, the interaction of the ionophore with positively charged ammonium ion of the APTESgrafted glass may also change the emission of the fluoroionophore 31 and affect the measurements by scanning fluorescence imaging. Thus, complementary measurements using 80 XPS and ToF-SIMS were performed to corroborate the scanning fluorescence imaging.…”

Nanoliter-scale, regenerable ion sensor: sensing with surface functionalized microstructured optical fiber

“…These characteristics have allowed MOFs to be used as sensing platforms for a variety of chemical and biological substrates. [13][14][15] In addition, integrating a photoswitchable molecule with MOFs as the sensor surface also means that light can also be used to quantify the binding of analytes via absorption, fluorescence or label-free techniques.…”