Development of "Smart" photodynamic theranostics agents

Cancer has been the leading cause of human deaths for more than a century. Research focusing on cancer treatment has always attracted many scientists’ attention. Radiotherapy and chemotherapy are the traditional methods to kill cancer cells effectively; however, their side effects can cause pains and suffering to the patients. Huge efforts have been invested to design targeted cancer therapy to minimize the harmful side effects and simultaneously kill the cancer cells efficiently. In recent decades, photodynamic therapy (PDT) has become an attractive cornerstone for targeted cancer therapy. With the use of photosensitizers and light irradiations, cancer cells can be killed selectively through the generation of cytotoxic reaction oxygen species while specific targeting could avoid undesired and unnecessary damage to normal cells. The use of light in medical application first appeared in 1900 in Professor von Tappeiner’s research group. They found that paramecia could be killed in the presence of light and acridine. Further discoveries enabled von Tappeiner’s group to determine that skin cancer can also be treated with the combination of light and a photosensitizer. Such a photosensitization process that could cause cell death was eventually named as “Photodynamic Therapy,” opening a new era in the cancer treatment history.¹ There are two main sequences in PDT. First, the administration of photosensitizer into the patient’s body and second, the activation of photosensitizer by non-thermal light of a specific wavelength. Upon activation, the photosensitizer will produce reactive oxygen species (ROS) which pose a cytotoxic effect to the proximity area.² Expeditious development of.... © 2021 Elsevier Ltd. All rights reserved.