**5.1 Other disease cured by PDT includes**

Chronic central serous chorioretinopathy is a retinal disorder that begins often at a very young age. The disease represents damage to the retinal pigment epithelium and photoreceptors. Synergistic application of PDT using verteporfin as the PS with other corresponding treatment modalities has been proven for curing the disease [131]. Loss of melanocytes gives rise to depigmentation leading to a skin disease called vitiligo. The remedy was not at all satisfying till now. In PDT using ALA with 0.5% of the drug has been proven to cure vitiligo [132, 133].

There have been reports of atherosclerosis treatment. It has been demonstrated that modest phototherapy along with PDT using a black TiO2 nanoprobe decreases intracellular lipid levels in atherosclerotic foam cells without inducing apoptosis. The nanoprobe was filled with PS porphine and hyaluronic acid to achieve the desired effect. PPT and PDT worked together to significantly reduce the thickness of the lipid cell layer [134].

*Porphyrinoid Photosensitizers for Targeted and Precise Photodynamic Therapy: Progress… DOI: http://dx.doi.org/10.5772/intechopen.109071*

## **6. Future prospective**

A promising area for cancer research is porphyrinoid photodynamic treatment, which has several potential theranostic uses. Porphyrinoids have potential in PDT, as we covered in the chapter, and theranostic is currently a study field that is expanding. These macrocyclic compounds have fluorescent characteristics that are useful for fluorescence imaging in diagnostic procedures. These substances are a prospective tool for MRI and PET imaging because of their ability to chelate with Mn, Fe, Gd, and Tc [135]. The treatment of multidrug-resistant tumors and antibiotic-resistant bacteria is always challenging, and PDT is an ideal alternative in such cases [49]. Researchers are now working on the condition called hypoxia occurring in the tumor—lack or decrease in oxygen content (hypoxia) in the TME, nanomedicines are currently employed to handle the strategy [136].

PDT plays an important role in the field of veterinary medicine because it shows encouraging results for the treatment of different animal pathologies such as bovine mastitis, malassezia, and cutaneous hemangiosarcoma [137]. Photodynamic therapy has many promising advantages to improve the quality of current treatment modalities along with easy diagnosis. Aptamer-targeted photodynamic therapy is a futuristic tool for tumor targeting, current studies showed 500-fold increased light-activated cytotoxicity and improved tissue-specific killing of cancer [138]. With light irradiation, the aptamer-modified PSs or PSs-containing nanocarriers produce significant levels of reactive oxygen species and provide improved photodynamic therapeutic efficacy in malignancies [138, 139].
