Stimulus-responsive inorganic semiconductor nanomaterials for tumor-specific theranostics

Nanotheranostics utilizing nanoparticles for diagnostics and treatment simultaneously, have attracted tremendous attention in anticancer therapy due to its excellent performance, such as distinct efficiency and specificity to tumor. Semiconductor nanomaterials, as a unique type of nanomaterials, have widely been harnessed for nanotheranostics because of the specific properties including the optical, magnetic and photoresponsive properties. Herein, this review firstly discussed serval types of semiconductor nanoparticles and the distinct properties for the potential biomedical applications. Metal chalcogenides, transition metal oxides and other inorganic semiconductors were overviewed for nanotheranostics application. Meanwhile, in order to improve the theranostics accuracy and efficiency, the exogenous and endogenous stimuli were comprehensively discussed. The exogenous stimuli, including light, magnetism, ultrasound, and radiation, which are commonly employed for imaging and therapy, were subsequently discussed according to the attributes. In addition, the tumor microenvironment (TME), which is well known as pH, reactive oxygen species (ROS), hypoxia, GSH, and enzymes, were tremendously utilized for TME-responsive sensor, therapy and drug release. In the end, the challenges and perspective of semiconductor nanomateraials for tumor-specific theranostics were also proposed.