Application of infrared waves in cancer therapy

Phototherapy techniques refer to light-activated medical treatments in which incident lights with specific wavelengths are used for therapeutic applications. The two most commonly used forms of phototherapy are photodynamic therapy and photothermal therapy, which are based on localized chemical and thermal damage to lesion sites, respectively. These two methods have gained considerable attention over the past decades as noninvasive and safe therapeutic modalities. However, numerous efforts have been made to increase the efficiency of these approaches and attain higher tumor specificity with fewer side effects for their practical clinical use. The phenomenon that has made this path more hopeful for researchers is the emergence of nanotechnology, which has undeniably played a critical role in overcoming the associated key challenges in this regard. Various nanomaterials with well-established sizes, shapes, chemical compositions, and surface functionalities have been exploited for photothermal applications. Great strides have been made in developing more efficient therapeutic agents, especially for cancer theranostics. In the present chapter, we first introduce photodynamic and photothermal therapy methods with a detailed discussion of their mechanisms of action. We then focus on the role of nanoparticle-based therapeutic approaches in overcoming the limitations of these two methods as well as in the development of more efficacious combinatorial cancer therapy strategies.