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An optofluidic temperature probe.

Węgrzyn I, Ainla A, Jeffries GD, Jesorka A - Sensors (Basel) (2013)

Bottom Line: We utilized two fluorescent rhodamines, which exhibit different fluorescent responses with temperature, and made ratiometric intensity measurements.The temperature dependence of the intensity ratio was calibrated and used in a model study of the thermal activation of TRPV1 ion channels expressed in Chinese hamster ovary cells.Our approach represents a practical and robust solution to the specific problem of measuring temperature in biological experiments in vitro, involving highly localized heat generation, for example with an IR-B laser.

View Article: PubMed Central - PubMed

Affiliation: Department of Chemical and Biological Engineering, Chalmers University of Technology, Kemivägen 10, Göteborg SE-412 96, Sweden. ilona.wegrzyn@chalmers.se

ABSTRACT
We report the application of a microfluidic device for semi-contact temperature measurement in picoliter volumes of aqueous media. Our device, a freely positionable multifunctional pipette, operates by a hydrodynamic confinement principle, i.e., by creating a virtual flow cell of micrometer dimensions within a greater aqueous volume. We utilized two fluorescent rhodamines, which exhibit different fluorescent responses with temperature, and made ratiometric intensity measurements. The temperature dependence of the intensity ratio was calibrated and used in a model study of the thermal activation of TRPV1 ion channels expressed in Chinese hamster ovary cells. Our approach represents a practical and robust solution to the specific problem of measuring temperature in biological experiments in vitro, involving highly localized heat generation, for example with an IR-B laser.

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Related in: MedlinePlus

Calibration curve of pipette thermometer, showing the relation between fluorescence intensity ratio IB/I6G and temperature T. Temperature dependent measurements were carried out in both directions (to account for a possible hysteresis), at two different flow rates and at two different distances of the channel outlets from the bottom plane. All error bars are given for the 95% confidence level.
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f3-sensors-13-04289: Calibration curve of pipette thermometer, showing the relation between fluorescence intensity ratio IB/I6G and temperature T. Temperature dependent measurements were carried out in both directions (to account for a possible hysteresis), at two different flow rates and at two different distances of the channel outlets from the bottom plane. All error bars are given for the 95% confidence level.

Mentions: After measuring the fluorescence intensities (single wavelength excited) of both dyes at different temperatures, a series of intensity ratios IB/I6G could be calculated and plotted vs. temperature. The data points were fitted by a second order polynomial (Figure 3). The temperatures for the calibration model were determined using a calibrated thermocouple (Figure 1). The dynamic range of the sensor does not exceed the temperature range relevant for biological systems. It is likely that different dye pairs can be used to address other desired dynamic ranges and sensitivity.


An optofluidic temperature probe.

Węgrzyn I, Ainla A, Jeffries GD, Jesorka A - Sensors (Basel) (2013)

Calibration curve of pipette thermometer, showing the relation between fluorescence intensity ratio IB/I6G and temperature T. Temperature dependent measurements were carried out in both directions (to account for a possible hysteresis), at two different flow rates and at two different distances of the channel outlets from the bottom plane. All error bars are given for the 95% confidence level.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC3673084&req=5

f3-sensors-13-04289: Calibration curve of pipette thermometer, showing the relation between fluorescence intensity ratio IB/I6G and temperature T. Temperature dependent measurements were carried out in both directions (to account for a possible hysteresis), at two different flow rates and at two different distances of the channel outlets from the bottom plane. All error bars are given for the 95% confidence level.
Mentions: After measuring the fluorescence intensities (single wavelength excited) of both dyes at different temperatures, a series of intensity ratios IB/I6G could be calculated and plotted vs. temperature. The data points were fitted by a second order polynomial (Figure 3). The temperatures for the calibration model were determined using a calibrated thermocouple (Figure 1). The dynamic range of the sensor does not exceed the temperature range relevant for biological systems. It is likely that different dye pairs can be used to address other desired dynamic ranges and sensitivity.

Bottom Line: We utilized two fluorescent rhodamines, which exhibit different fluorescent responses with temperature, and made ratiometric intensity measurements.The temperature dependence of the intensity ratio was calibrated and used in a model study of the thermal activation of TRPV1 ion channels expressed in Chinese hamster ovary cells.Our approach represents a practical and robust solution to the specific problem of measuring temperature in biological experiments in vitro, involving highly localized heat generation, for example with an IR-B laser.

View Article: PubMed Central - PubMed

Affiliation: Department of Chemical and Biological Engineering, Chalmers University of Technology, Kemivägen 10, Göteborg SE-412 96, Sweden. ilona.wegrzyn@chalmers.se

ABSTRACT
We report the application of a microfluidic device for semi-contact temperature measurement in picoliter volumes of aqueous media. Our device, a freely positionable multifunctional pipette, operates by a hydrodynamic confinement principle, i.e., by creating a virtual flow cell of micrometer dimensions within a greater aqueous volume. We utilized two fluorescent rhodamines, which exhibit different fluorescent responses with temperature, and made ratiometric intensity measurements. The temperature dependence of the intensity ratio was calibrated and used in a model study of the thermal activation of TRPV1 ion channels expressed in Chinese hamster ovary cells. Our approach represents a practical and robust solution to the specific problem of measuring temperature in biological experiments in vitro, involving highly localized heat generation, for example with an IR-B laser.

Show MeSH
Related in: MedlinePlus