A multicouple probe for temperature gradient measurements in biological materials.

Area of Science:

• Biomedical Engineering
• Medical Devices
• Sensor Technology

Background:

• Accurate in vivo tissue temperature measurement is crucial for understanding physiological processes and diagnosing conditions.
• Existing methods for temperature profiling can be invasive, bulky, or lack spatial resolution.

Purpose of the Study:

• To develop and characterize a novel, easy-to-make, sensitive, thin, and flexible multisensor probe for in vivo tissue temperature profile measurement.
• To assess the accuracy and reliability of the probe under varying thermal gradient conditions.

Main Methods:

• Construction of a type-T thermocouple multicouple probe with a diameter < 1 mm using 38-gauge copper and 36-gauge constantan wires.
• Introduction of the multicouple into a polyethylene tube, allowing for temperature measurements at 5-mm intervals over an 8-cm range.
• Extensive calibration for the thermal conductivity (k) effect using a limb model to correct for gradient-induced inaccuracies.

Main Results:

• The multisensor probe allows for instantaneous measurement of tissue temperature profiles at 5-mm intervals.
• Temperature readings are significantly affected by the k effect in the presence of thermal gradients.
• Calibration for the k effect ensures a measurement accuracy of +/- 0.1°C across a wide range of thermal gradients.

Conclusions:

• The developed multisensor probe is a sensitive, thin, and flexible tool for accurate in vivo tissue temperature profiling.
• The probe's design and calibration method effectively mitigate the impact of thermal conductivity effects.
• This device holds potential for implantation in tissues to monitor thermal gradients under diverse physiological conditions.