4 - Biomedical nanoparticle carriers with combined thermal and magnetic response

Abstract

Nanostructured carriers with dual characteristics that combine two different approaches have been the object of intense research worldwide and constitute an interesting advance in research into procedures that aim to treat diseases and cancer. Some systems combine the use of two different drugs to treat cancer. Simultaneously, these drugs can act at different phases of the cell cycle aiming to arrest the cells’ growth after they developed chemoresistance. Other systems have combined the thermal and magnetic properties, seeking to obtain advantages on the control of the release kinetics or modulating a treatment, giving more specificity of action. As the temperature of the human body remains almost stable at 37°C, a slight local heating, observed in some pathological conditions such as inflammation and infection can represent an important opportunity to biomedical nanosystems for selective temperature-responsive release of their contents. The combination of both magnetic and thermal properties is often more suitable, as an external magnetic field can force align or move nanoparticles and provide an adequate means of remote heating in part of a tissue. Temperature can trigger a change in surface properties, modifying the size, water content, and diffusivity of radioisotopes. Still under the action of an adequate magnetic field, thermal-responsive and magnetic hybrid nanosystems can release, selectively, drugs and allow the separation/immobilization of proteins in specific sites. As organic-constituted nanomaterials are not suitable for magnetic applications, only hybrid systems (inorganic and organic) can be used in this approach. The present chapter aims to review the most recent advances in biomedical nanoparticle carriers that combine thermal and magnetic responses, detailing the mainly inorganic materials used as core and as well as the temperature-responsive polymers more commonly applied as an organic part of these new, hybrid, therapeutic nanosystems.