# Photodynamic Therapy--An Up-to-Date Review
## 4 Nanomaterials for Photodynamic Therapy
\begin{table}
\begin{tabular}{c c c c c} \hline
**Photosensitizer** & **Absorption Range** & **Approval Status** & **Potential Applications** & **Refs.** \\ \hline Indocyanine green (ICG) & Near-infrared (-800 nm) & FDA approved (for diagnostic in cardiology, hepatology, ophthalmology, fluoressence-guided cancer surgery) & Topical melanoma PDT, management of chronic periodontitis & [46; 47; 48] \\ \hline Methylene blue & 600–665 nm & Approved in Canada (for periodontal diseases and nasal decolonization of _Staphylococcus aureus_) & Photoantimicrobial activity against yeasts and filamentous fungi, dental caries, basal cell carcinoma & [19; 49; 50; 51; 52] \\ \hline Rose Bengal & 500–550 nm & Dental caries & [19; 50] \\ \hline Curcumin & 300–500 nm & Not yet approved & Local superficial infections and cancers & [1; 37] \\ \hline Thiophenes & 225–400 nm & Skin and cervix cancer & [1] \\ \hline
5-Aminolevulinic acid (ALA) & 410–630 nm & FDA approved (for dermatology indications) & Hypertrophic actinic keratoses on the face and scalp, vulvar lichen sclerosis, glioblastoma & [6; 53; 54] \\ \hline Methyl aminolevulinate (MAL) & \textasciognognolumn{2}{c}{FDA approved (for dermatology indications)} & Actin keratoses, basal cell carcinoma, Bowen disease, viral warts & [6; 11; 55] \\ \hline Hexvix/Cysview & 380–450 nm & EU and FDA approved (for intravesical administration and diagnosis of bladder cancer) & Bladder cancer, prostate cancer, colon cancer & [56; 57] \\ \hline Meta-tetrahydroc-phenylchlorin (m-THPC) & \textasciognolumn{2}{c}{Approved in EU (for palliative treatment of patients with advanced head and neck cancer)} & Pancreatic cancer, biliary cancer, breast cancer metastases & [45; 52; 58] \\ \hline Lutetium texaphyrin & \textasciognolumn{2}{c}{-732 nm} & Phase I trial (for locally recurrent prostate cancer) & Skin metastases, breast cancer & [45; 52] \\ \hline Verteporfin & \textasciognolumn{2}{c}{-689 nm} & Approved in Japan (for subfoveal choroidal neovascularization in wet age-related macular degeneration) & Central serous chorioretinopathy (CSCR), choroidal hemangioma, gastric cancer & [6; 69; 70; 71] \\ \hline Talaporfin sodium & \textasciognolumn{2}{c}{-664 nm} & Approved in Japan (for early endobronchial carcinoma) & Esophageal cancer, gastric cancer, bile duct carcinoma & [52; 59; 62; 63] \\ \hline \end{tabular}
\end{table} 
Table 1: Cont. Due to its low toxicity, inertness, and good biocompatibility, gold is one of the preferred materials among metallic nanoparticles. Moreover, its affinity towards thiol and amine groups allows facile surface functionalization with ligands like antibodies, proteins, nucleic acids, and carbohydrates [14; 29; 67; 68]. Gold nanocages, nanorods, and nanoshells are considered brilliant photo-response structures, capable of sensitizing singlet oxygen formation and generating ROS that can destroy cancer cells [69]. Gold nanoclusters were reported as effective delivery vehicles for clinically approved PSs, providing spatiotemporal control and diminishing undesirable side effects [70]. Silver is another material of interest in PDT because, besides its ability to generate singlet oxygen, it also has antimicrobial properties [14; 64; 71; 72; 73]. Ag nanoparticles' large specific area increases the contact area between this material and bacteria or viruses, thus enhancing its bactericidal effect. Moreover, when being used as nanocontainers of PSs, these particles perform a bimodal action, increasing the efficiency of fault detection and isolation of microorganisms [8; 74]. Copper sulfide nanoparticles are widely used in PDT as they are cheap, simple, easy to prepare, and can be surface functionalized [8]. CuS nanoparticles also present photothermal and photodynamic properties that, coupled with their insignificant cytotoxicity, make them suitable for bacteria eradication from infected wounds [75]. CuS nanodots can also serve as the base material for nanotheranostics with excellent biocompatibility [76].