pH-sensitive holograms for continuous monitoring in plasma

Medlock, Kathryn E. S.; Harmer, Hazel E.; Worsley, Graham J.; Horgan, Adrian; Pritchard, John

doi:10.1007/s00216-007-1548-9

Cited by 12 publications

(4 citation statements)

References 24 publications

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“…Newer optical methods offer the promise of miniaturisation and continuous in vivo measurements without drift. The ability of a holographic sensor based on a thin-film, biocompatible hydrogel (approximately 10 μm) of poly(2-hydroxyethyl methacrylate) and ionisable 2-(dimethylaminoethyl) methacrylate to accurately measure the pH of blood plasma ex vivo was investigated in [62]. It was found that the sensors behave in a fully reversible manner.…”

Section: Polymers and Methods Used For Ph Measurementsmentioning

confidence: 99%

State Key Laboratory of Nonlinear Mechanics (LNM), Institute of Mechanics, Chinese Academy of Sciences, Beijing 100080, China

Korostynska

Arshak

Gill

et al. 2007

Sensors

162

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Section: Polymers and Methods Used For Ph Measurementsmentioning

confidence: 99%

State Key Laboratory of Nonlinear Mechanics (LNM), Institute of Mechanics, Chinese Academy of Sciences, Beijing 100080, China

Korostynska

Arshak

Gill

et al. 2007

Sensors

162

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“…Optical pH sensing implemented with fiber optics [ 6 , 7 , 8 , 9 ] has been previously investigated as an alternative to a glass electrode for biomedical measurements because it combines small size and calibration stability. A pH indicator is immobilized at the distal end of an optical fiber by adsorption, covalent bonding, or entrapment.…”

Section: Introductionmentioning

confidence: 99%

Synthesis and Characterization of N-Isopropylacrylamide Microspheres as pH Sensors

Lavine

Kaval

Oxenford

et al. 2021

Sensors

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Swellable polymer microspheres that respond to pH were prepared by free radical dispersion polymerization using N-isopropylacrylamide (NIPA), N,N′-methylenebisacrylamide (MBA), 2,2-dimethoxy-2-phenylacetylphenone, N-tert-butylacrylamide (NTBA), and a pH-sensitive functional comonomer (acrylic acid, methacrylic acid, ethacrylic acid, or propacrylic acid). The diameter of the microspheres was between 0.5 and 1.0 μm. These microspheres were cast into hydrogel membranes prepared by mixing the pH-sensitive swellable polymer particles with aqueous polyvinyl alcohol (PVA) solutions followed by crosslinking with glutaric dialdehyde for use as pH sensors. Large changes in the turbidity of the PVA membrane were observed as the pH of the buffer solution in contact with the membrane was varied. These changes were monitored by UV–visible absorbance spectroscopy. Polymer swelling of many NIPA copolymers was reversible and independent of the ionic strength of the buffer solution in contact with the membrane. Both the degree of swelling and the apparent pKa of the polymer microspheres increased with temperature. Furthermore, the apparent pKa of the polymer particles could be tuned to respond sharply to pH in a broad range (pH 4.0–7.0) by varying the amount of crosslinker (MBA) and transition temperature modifier (NTBA), and the amount, pKa, and hydrophobicity of the pH-sensitive functional comonomer (alkyl acrylic acid) used in the formulation. Potential applications of these polymer particles include fiber optic pH sensing where the pH-sensitive material can be immobilized on the distol end of an optical fiber.

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“…pH optrodes usually consist of a pH indicator bound onto a solid support or immobilized in a polymer matrix at the distal end of an optical fiber [7]. Interaction of the indicator at the end of the fiber with the sample leads to changes in Molecules 2020, 25 the optical properties of the indicator which is detected through the optical fiber by absorbance or fluorescence from the sensing material [8,9]. Optrodes have several advantages over glass electrodes including low cost, small size and the robustness of the optical fiber.…”

Section: Introductionmentioning

confidence: 99%

Swellable Copolymers of N-isopropylacrylamide and Alkyl Acrylic Acids for Optical pH Sensing

et al. 2020

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Swellable polymers that respond to pH (including a portion of the physiological pH range) have been prepared from N-isopropylacrylamide (NIPA) copolymerized with acrylic acid, methacrylic acid, ethacrylic acid or propacrylic acid by dispersion polymerization. When the swellable polymer particles are dispersed in a polyvinyl alcohol (PVA) hydrogel membrane, large changes occur in the turbidity of the membrane (which is measured using an absorbance spectrometer) as the pH of the buffer solution in contact with the hydrogel membrane is varied. The swelling of the NIPA copolymer is nonionic, as the ionic strength of the buffer solution in contact with the PVA membrane was increased from 0.1 to 1.0 M without a decrease in the swelling. For many of these NIPA copolymers, swelling was also reversible in both low- and high ionic strength pH-buffered media and at ambient and physiological temperatures. The composition of the formulation used to prepare these copolymers of NIPA can be correlated to the enthalpy and entropy of the pH-induced swelling.

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pH-sensitive holograms for continuous monitoring in plasma

Cited by 12 publications

References 24 publications

State Key Laboratory of Nonlinear Mechanics (LNM), Institute of Mechanics, Chinese Academy of Sciences, Beijing 100080, China

State Key Laboratory of Nonlinear Mechanics (LNM), Institute of Mechanics, Chinese Academy of Sciences, Beijing 100080, China

Synthesis and Characterization of N-Isopropylacrylamide Microspheres as pH Sensors

Swellable Copolymers of N-isopropylacrylamide and Alkyl Acrylic Acids for Optical pH Sensing

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