The developed thionated photosensitizers do not exhibit cytotoxicity in the dark, while show good photodynamic efficacy against cancer cells and 3D multicellular tumor spheroids.80 The authors further conjugated the thionated photosensitizers to the trastuzumab, a monoclonal antibody targeting human epidermal growth factor receptor 2 (HER2), to achieve tumor-specific delivery and demonstrated their tumor-specific therapeutic activity against a HER2-positive cell line. Here, ERBB2 is linked to neoplasm.