Limits...
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.

Show MeSH

Related in: MedlinePlus

Concept of the microfluidic temperature probe with optical readout. (A) Schematic perspective view of the multifunctional pipette, which generates a hydrodynamically confined flow (HCF) in the environment where the temperature is probed. The content of this virtual flow cell can be quickly multiplexed between the strongly and weakly temperature responsive dyes. (B) The fluorescence signal of Rhodamine B (RhB) IB rapidly drops with increasing temperature, while the fluorescence intensity of Rhodamine 6G (Rh6G) I6G is only slightly influenced by temperature change. Outlined within is the concept of coupling the alternation of a change in temperature. (C) Micrograph of the multifunctional pipette in the calibration setup on top of a surface printed thin film heater (dark areas in left and right bottom corners) and a type E microthermocouple as a reference sensor. (D) Fluorescence image of the rhodamine HCF generated at the tip of the pipette (top down view). The diagonal line observed, is an artifact due to the pipette contacting the surface, which does not interfere with the flow or function.
© Copyright Policy
Related In: Results  -  Collection

License
getmorefigures.php?uid=PMC3673084&req=5

f1-sensors-13-04289: Concept of the microfluidic temperature probe with optical readout. (A) Schematic perspective view of the multifunctional pipette, which generates a hydrodynamically confined flow (HCF) in the environment where the temperature is probed. The content of this virtual flow cell can be quickly multiplexed between the strongly and weakly temperature responsive dyes. (B) The fluorescence signal of Rhodamine B (RhB) IB rapidly drops with increasing temperature, while the fluorescence intensity of Rhodamine 6G (Rh6G) I6G is only slightly influenced by temperature change. Outlined within is the concept of coupling the alternation of a change in temperature. (C) Micrograph of the multifunctional pipette in the calibration setup on top of a surface printed thin film heater (dark areas in left and right bottom corners) and a type E microthermocouple as a reference sensor. (D) Fluorescence image of the rhodamine HCF generated at the tip of the pipette (top down view). The diagonal line observed, is an artifact due to the pipette contacting the surface, which does not interfere with the flow or function.

Mentions: We present here an open-volume and fluorescence based temperature measurement technique utilizing two rhodamine solutions in a hydrodynamically confined flow (HCF) device (Figure 1). By means of the previously reported multifunctional pipette (MFP) [23], a positionable open volume microfluidic device, we construct an optofluidic semi-contact thermometer which can be readily applied in microscopy experiments of biological and artificial cells, or tissue samples.


An optofluidic temperature probe.

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

Concept of the microfluidic temperature probe with optical readout. (A) Schematic perspective view of the multifunctional pipette, which generates a hydrodynamically confined flow (HCF) in the environment where the temperature is probed. The content of this virtual flow cell can be quickly multiplexed between the strongly and weakly temperature responsive dyes. (B) The fluorescence signal of Rhodamine B (RhB) IB rapidly drops with increasing temperature, while the fluorescence intensity of Rhodamine 6G (Rh6G) I6G is only slightly influenced by temperature change. Outlined within is the concept of coupling the alternation of a change in temperature. (C) Micrograph of the multifunctional pipette in the calibration setup on top of a surface printed thin film heater (dark areas in left and right bottom corners) and a type E microthermocouple as a reference sensor. (D) Fluorescence image of the rhodamine HCF generated at the tip of the pipette (top down view). The diagonal line observed, is an artifact due to the pipette contacting the surface, which does not interfere with the flow or function.
© Copyright Policy
Related In: Results  -  Collection

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

f1-sensors-13-04289: Concept of the microfluidic temperature probe with optical readout. (A) Schematic perspective view of the multifunctional pipette, which generates a hydrodynamically confined flow (HCF) in the environment where the temperature is probed. The content of this virtual flow cell can be quickly multiplexed between the strongly and weakly temperature responsive dyes. (B) The fluorescence signal of Rhodamine B (RhB) IB rapidly drops with increasing temperature, while the fluorescence intensity of Rhodamine 6G (Rh6G) I6G is only slightly influenced by temperature change. Outlined within is the concept of coupling the alternation of a change in temperature. (C) Micrograph of the multifunctional pipette in the calibration setup on top of a surface printed thin film heater (dark areas in left and right bottom corners) and a type E microthermocouple as a reference sensor. (D) Fluorescence image of the rhodamine HCF generated at the tip of the pipette (top down view). The diagonal line observed, is an artifact due to the pipette contacting the surface, which does not interfere with the flow or function.
Mentions: We present here an open-volume and fluorescence based temperature measurement technique utilizing two rhodamine solutions in a hydrodynamically confined flow (HCF) device (Figure 1). By means of the previously reported multifunctional pipette (MFP) [23], a positionable open volume microfluidic device, we construct an optofluidic semi-contact thermometer which can be readily applied in microscopy experiments of biological and artificial cells, or tissue samples.

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