Qing Xiang and Paulo Cesar Morais
The huge demand for biocompatible, robust, accurate and noninvasive technology to assess the temperature of a biological targeted site for monitoring the hyperthermia effect brings the topic of remote thermometry to a very high level of interest. There are already promising research directions to fulfil such demand in the short term and a review of the achievements in this issue is certainly worth. This report offers an overview of the research regarding the most promising nanothermometers nowadays, with emphasis on those addressed to remote operation while using optical or magnetic responses of nanosized materials as the thermometric property. More specifically the optical emission intensity, optical emission peak shift and optical emission lifetime will be covered as far as the optical-based nanothermometers are concerned. Additionally, for the magnetic-based nanothermometers the magnetization or the magnetic susceptibility are the thermometric properties covered in this review. Furthermore, the review includes the hyperthermia effect based on nanosized metallic or magnetic particles plus a couple of thermally-responsive polymeric drug delivery systems, aiming to provide an integrated view of the multipurpose platform offered by actuating-sensing nanoparticles. As far as the regulatory system is concerned the availability of noninvasive thermometry incorporating biocompatibility, robustness and accuracy will establish the grounds needed for the approval of the hyperthermia technology for therapeutic purposes, thus allowing the market of this technological option on a global scale.