Background:　Photodynamic　therapy　(PDT),　a　clinical　anticancer　therapeutic　modality,　has　a　long　history　in　clinical　cancer　treatments　since　the　1970s.　However,　PDT　has　not　been　widely　used　largely　because　of　metabolic　problems　and　off-target　phototoxicities　of　the　current　clinical　photosensitizers.　Purpose:　The　objective　of　the　study　is　to　develop　a　high-efficiency　and　high-specificity　carrier　to　precisely　deliver　photosensitizers　to　tumor　sites,　aiming　at　addressing　metabolic　problems,　as　well　as　the　systemic　damages　current　clinical　photosensitizers　are　known　to　cause.　Methods:　We　synthesized　a　polydopamine　(PDA)-based　carrier　with　the　modification　of　folic　acid　(FA),　which　is　to　target　the　overexpressed　folate　receptors　on　tumor　surfaces.　We　used　this　carrier　to　load　a　cationic　phthalocyanine-type　photosensitizer　(Pc)　and　generated　a　PDA-FA-Pc　nanomedicine.　We　determined　the　antitumor　effects　and　the　specificity　to　tumor　cell　lines　in　vitro.　In　addition,　we　established　human　cancer-xenografted　mice　models　to　evaluate　the　tumor-targeting　property　and　anticancer　efficacies　in　vivo.　Results:　Our　PDA-FA-Pc　nanomedicine　demonstrated　a　high　stability　in　normal　physiological　conditions,　however,　could　specifically　release　photosensitizers　in　acidic　conditions,　eg,　tumor　microenvironment　and　lysosomes　in　cancer　cells.　Additionally,　PDA-FA-Pc　nanomedicine　demonstrated　a　much　higher　cellular　uptake　and　phototoxicity　in　cancer　cell　lines　than　in　healthy　cell　lines.　Moreover,　the　in　vivo　imaging　data　indicated　excellent　tumor-targeting　properties　of　PDA-FA-Pc　nanomedicine　in　human　cancer-xenografted　mice.　Lastly,　PDAFA-　Pc　nanomedicine　was　found　to　significantly　suppress　tumor　growth　within　two　human　cancer-xenografted　mice　models.　Conclusion:　Our　current　study　not　only　demonstrates　PDA-FA-Pc　nanomedicine　as　a　highly　potent　and　specific　anticancer　agent,　but　also　suggests　a　strategy　to　address　the　metabolic　and　specificity　problems　of　clinical　photosensitizers.　©　2019　Yan　et　al.