Development of a new theoretical model for blood-CNTs effective thermal conductivity pertaining to hyperthermia therapy of glioblastoma multiform

BACKGROUND AND OBJECTIVE The present study deals with the hyperthermia therapy, which is the type of treatment in which tissues are exposed to high temperatures in order to destroy cancer cells with minimal injury to healthy tissues. In particular, it focuses on glioblastoma multiform, which is the most aggressive cancer that begins within the brain. Conventional treatments display limitations that can be overcome by using nanoparticles for targeted heating. Out of the proposed nanoparticles, this investigation focuses on a new field that utilizes carbon nanotubes (CNTs) which are able to selectively heat the cancer cells since they can convert near infrared light into heat. In the absence of any experiment or theoretical model for the estimation of an effective thermal conductivity of blood and CNTs, a first principle model is developed in this study which takes into account the blood micro-structure. Besides, a number of factors are included, namely the shape and the size of the nanoparticles, the interfacial layer formed around them and their volume fraction. METHODS Firstly, assuming that the blood consists of blood cells and plasma, the thermal conductivity of the former is estimated. Then, the effective thermal conductivity of plasma/CNTs is calculated for various parameters. Finally, the resulting "bio-nanofluid" consisting of plasma/CNTs and blood cells is formed. RESULTS It is ascertained that thin and elongated CNTs with relatively large nanolayer thickness as well as large concentrations of CNTs contribute to the increase of the thermal conductivity and, thus, in the enhancement of the heat transfer. CONCLUSIONS Investigating of how design parameters pertaining to CNTs, such as their size and shape, affect the effective thermal conductivity of blood-CNTs, possible regulating ways are suggested regarding the hyperthermic treatment. Finally, the present simple estimation of the effective thermal conductivity can be used as an effective property of the nanofluid when it comes to numerical investigations regarding heat transfer occurring during hyperthermia or other potential clinical uses (for example targeted heat of living tissues).