“…According to the nanostructure, nanoparticles can be generally categorized into three types: 1) NPs with mixed hydrophilic and hydrophobic domains, 2) NPs with a core-shell structure, and 3) NPs with a double-layered capsule structure ( Figure 2 ). In this respect, natural polysaccharides such as hyaluronic acid (HA) [ 102 , 103 , 104 , 105 ], chitosan [ 102 , 106 , 107 , 108 ], chitin, heparin [ 95 , 99 , 100 ], and fucoidan [ 84 ] have been utilized as potential photosensitizer carriers due to their biocompatibility and biodegradability. In addition, not only polymers but also hydrophobic small molecule anticancer drugs (such as doxorubicin [ 96 ], docetaxel [ 97 , 107 , 109 , 110 ], paclitaxel [ 85 , 93 , 103 , 111 , 112 ], camptothecin, and quercetin [ 113 , 114 ]) can be grafted onto PS.…”