In vivo measurement of skin heat capacity: advantages of the scanning calorimetric sensor

Abstract

Measurement of the heat capacity of human tissues is mainly performed by differential scanning calorimetry. In vivo measurement of this property is an underexplored field. There are few instruments capable of measuring skin heat capacity in vivo. In this work, we present a sensor developed to determine the heat capacity of a 4 cm2 skin area. The sensor consists of a thermopile equipped with a programmable thermostat. The principle of operation consists of a linear variation of the temperature of the sensor thermostat, while the device is applied to the skin. To relate the heat capacity of the skin with the signals provided by the sensor, a two-body RC model is considered. The heat capacity of skin varies between 4.1 and 6.6 JK−1 for a 2 × 2 cm2 area. This magnitude is different in each zone and depends on several factors. The most determining factor is the water content of the tissue. This sensor can be a versatile and useful tool in the field of physiology.