The impact of alternating and rotating regimes on the heating characteristics of magnetic bacterial cellulose structure

Abstract

The hyperthermia efficiency itself and the heating effect are determined not only by the material properties but also by the technical-application factors. For this reason, we subjected our experimental materials to experiments in an alternating magnetic field (AMF) as well as in a rotating magnetic field (RMF). According to the known numerical models as well as the results of comparative experiments, the RMF used is expected to be more efficient in heat generation than the AMF. Such tendency can be changed in the systems of higher density. This affects the particles' freedom of movement during field application, and thus there is a block of rotation. To research this, bacterial cellulose (BC) was magnetized in contact with magnetic fluid. By magnetic modification of BC, another range of potential applications is opened up including hyperthermia. Obtained specific absorption rates (SAR) at 3 different frequencies point to the possibility of effective tuning of the heating effect in conditions of alternating magnetic fields. Preliminary temperature evolution data of magnetized cellulose samples in both RMF and AMF indicate an increase in heating rate with applied field intensity proportional to H2 up to 4.3 kA∙m−1. In this AMF value, an inflection point is observed when data are plotted as d2T/dt2. In the case of RMF such tendency is not observed which permits a better temperature evolution prediction even in higher applied fields.