Applications of phototheranostic nanoagents in photodynamic therapy

Nanotherapeutics has an increasing role in the treatment of diseases such as cancer. In photodynamic therapy (PDT) a therapeutically inactive photosensitizer compound is selectively activated by light to produce molecules capable of killing diseased cells and pathogens. A phototheranostic agent can be defined as a single nanoentity with the capabilities for targeted delivery, optical imaging and photodynamic treatment of a disease. Malignant cells, tissue and microbial etiologic agents can be effectively targeted by PDT. Photodynamic therapy is noninvasive, or minimally invasive, and has few side effects as damage to healthy tissue is minimized and the killing effect is localized. Various forms of cancer, acne and other diseases may be treated. The in vivo efficacy of photosensitizers is further improved by attaching them to nanostructures capable of targeting the diseased site. Such photosensitizer-functionalized nanostructures, or nanotherapeutics, allow site-specific delivery of imaging and therapeutic agents for improved phototheranostic performance. This review explores the potential applications of phototheranostic nanostructures in diagnosis and therapy.