Dedicated Wearable Sensitive Strain Sensor, based on Carbon Nanotubes, for Monitoring the Rat Respiration Rate

Cardiovascular disease is a group of disorders of the heart and blood vessels, including coronary heart disease, cerebrovascular disease, and rheumatic heart disease, etc. It is one of the most common causes of death in the world. In 2013, cardiovascular disease claimed a total of 17.3 million lives (31.% of total deaths), which is a significant increase from 12.3 million in 1990 (25.8% of total deaths).

There is an increasing demand for a reliable heart monitoring system to capture intermittent abnormalities and detect serious heart behaviors, leading to sudden death in extreme cases. In addition to cardiac monitoring, there is a growing need to capture the respiratory function in several contexts such as sleep apneas. For example, “Internet-of-Medical-Things (IoMT)” are now considered to be a good strategy for monitoring the abnormalities of breathing and cardiac rate. A wearable monitoring strain sensor detects the accidents and sends immediately the information to the medical staff.

Therefore, there is a need to develop a highly sensitive, durable, and biocompatible strain sensor. In this paper, a new one-dimensional nanomaterial based strain sensor will be introduced for the respiratory rate monitoring of an anesthetized rat, followed by the fabrication process and the experimental platform. The dedicated sensitive sensor, based on carbon nanotubes mixed with poly(3,4-ethylenedioxythiophene) polystyrene sulfonate, was attached above the rat chest. A Wheatstone bridge electrical circuit, associated with a multifunction portable device, was connected to the strain sensor. The change of the strain sensor’s resistance value, induced by the mechanical deformability during the rat respiration, was detected and transformed into a voltage signal. The respiration information could be thus extracted and analyzed.