Nanotechnologies in Oncology: Photodynamic Therapy Approaches

Nano-oncology, the application of nanomedicine to cancer treatments, has the potential to transform clinical oncology by enhancing the efficacy of various cancer therapies. Photodynamic therapy (PDT) cancer treatment involves the administration of a photosensitizer (PS) to a patient’s localized tumor. Once the PS is accumulated within a target tumor site, it can be activated with laser irradiation at a particular wavelength and so produce reactive oxygen and cytotoxic species, which in turn destroy cancer cells. However, the administration of PSs alone within PDT cancer treatments has noted many pitfalls, such as limited uptake in tumor cells, phototoxicity, poor tissue distribution, and rapid clearance from the body, hindering the effectiveness of such treatments. Nevertheless, the combination of PSs with nanoparticles enables novel drug delivery systems to be developed, which can effectively target tumor sites with several functional molecules, including tumor-specific ligands, antibodies, and cytotoxic agents. These PS nanoparticle targeting conjugates can improve PS uptake and retention in tumor cells, allowing for significantly improved localized PDT cancer treatment outcomes, with reduced systemic and phototoxicity results. For this reason, nano-oncology is attracting considerable scientific interest, and its combinative application within PDT cancer treatments is rapidly being researched. This review highlights the progress, challenges, and opportunities in PDT cancer nanomedicine, as well as discusses the novel PS nanoengineering approaches that have been investigated in order to develop far more effective PDT nanotherapeutic treatment approaches for cancer patients.