| 1. |
- Hammarling, Krister, 1968-, et al.
(författare)
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A combined glucose and pH sensor on a single optical fiber for continuous point-of-care testing
- 2018
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Ingår i: SPIE BIOS, Optical Fibers and Sensors for Medical Diagnostics and Treatment Applications XVIII. - : SPIE - International Society for Optical Engineering.
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- Stress-induced hyperglycemia is very common for patients in intensive care units, which can become fatal if left uncontrolled. Blood glucose concentrations for patients at the intensive care units should therefore be monitored at all times. To be successful in monitoring the glucose concentrations of patients, the sensor needs to be fast, accurate and able to measure in real time. In addition, the pH level should be monitored, as a diagnostic parameter by itself, or to improve the reliability of the glucose measurement. To address this challenge, a fiber optic sensor for dual parameter measurement of glucose concentration and pH level for use in point-of-care testing has been developed. The sensor utilizes two stimuli responsive hydrogels to create two interferometers combined on one single mode fiber. The sensor is created by splicing a short section of thin-core fiber (SM450) coated with a pH-sensitive polymer, which constitutes a Mach-Zehnder type interferometer. The glucose is measured with a low finesse Fabry-Perot cavity made by polymerizing a glucose sensitive hydrogel hemisphere at the end face of the fiber. A versatile Fourier transform based, low pass filter was developed, which enable evaluation of the two signals independently. Our results show the feasibility of measuring glucose concentration and pH level by using a single fiber. This dual parameter and single point fiber optic biosensor is expected to be of great interest for in vivo measurements in medical applications where pH and glucose, as specific markers are monitored in real time, during or after surgery.
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| 2. |
- Hammarling, Krister, 1968-, et al.
(författare)
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Broad-range hydrogel-based pH sensor with capacitive readout manufactured on a flexible substrate
- 2018
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Ingår i: Chemosensors. - Basel, Switzerland : MDPI AG. - 2227-9040. ; 6:3
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Tidskriftsartikel (refereegranskat)abstract
- Environmental monitoring of land, water and air, is an area receiving greater attention because of human health and safety concerns. Monitoring the type of pollution and concentration levels is vital, so that appropriate contingency plans can be determined. To effectively monitor the environment, there is a need for new sensors and sensor systems that suits these type of measurements. However, the diversity of sensors suitable for low, battery powered- and large area sensor systems are limited. We have manufactured and characterized a flexible pH sensor using laser processing and blade coating techniques that is able to measure pH between 2.94 and 11.80. The sensor consists of an interdigital capacitance with a pH sensitive hydrogel coating. Thin sensors can reach 95% of their final value value within 3 min, and are stable after 4 min. Good repeatability was achieved in regard to cycling of the sensor with different pH and multiple measurements from dry state. We have also studied the relation between an interdigital capacitance penetration depth and hydrogels expansion. We believe that our passive sensor is suitable to be used in low power and large area sensor networks.
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| 3. |
- Hammarling, Krister, 1968-, et al.
(författare)
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Synthesis, Curing Behavior and Swell Tests of pH-Responsive Coatings from Acryl-Terminated Oligo(beta-Amino Esters)
- 2018
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Ingår i: CHEMOSENSORS. - : MDPI AG. - 2227-9040. ; 6:1
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Tidskriftsartikel (refereegranskat)abstract
- The ability of acryl-terminated oligo(beta-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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| 4. |
- Muri, H. I., et al.
(författare)
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Combining interferometric sensors for dual parameter fiber optic chemical sensing
- 2018
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Ingår i: Optics InfoBase Conference Papers. - : OSA - The Optical Society. - 9781557528209
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Konferensbidrag (refereegranskat)abstract
- Long and short path length differences interferometric sensing modalities have been combined based on immobilizing hydrogel on thin-core optical fiber end face. Dual parameter sensing of hydrogel swelling and refractive index was demonstrated.
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