Herein, in this study, we report the used of biofunctional nanoconjugates (BNC) composed of ZnPcS4 bound to antibody (anti GCC-mAb) functionalized AuNPs for targeted ZnPcS4 PS delivery through the binding on the GCC receptors expressed on target Caco-2 cells, with the purpose of exploring the concept of active targeting, enhancing PS cellular uptake and consequently enhancing the overall PDT efficacy on human colorectal cancer cell line, Caco-2. This evidence concerns the gene GUCY2C and colorectal cancer.