Multifunctional molecular devices armed with cancer-tracking and drug-activating features have been successfully developed to treat metastatic breast cancer in this project. Initially, modular, multifunctional and programmable molecular devices comprising a gold core, a navigator that enables binding to cancer biomarker(s) and an activator that induce drug release of cancer cells were synthetically assembled. These devices were tested against metastatic breast cancer cells and demonstrated good biocompatibility, cancer-targeting, and drug release capabilities. Overall, this project has successfully identified programmed death-ligand 1 (PD-L1) as a viable cancer biomarker for the targeted delivery of the device, established a drug release mechanism in cellular environments, and most importantly, developed an unprecedented cancer-targeting technology that can be programmed to non-invasively target metastatic breast cancer cells with high precision and selectivity without affecting normal cells. In recognition of the clinical potential of this cancer-selective, effective, and safe anti-cancer technology, this project has gained further funding, including a P2D translational funding and ITPA-Wellcome Trust Springboard funding from University of Edinburgh to further develop the cancer-targeting technology to enter clinical translation. The key results of this project have been further disseminated in scientific meetings, conferences, pitch competition, and commercialisation workshops, establishing extensive network within CRUK Edinburgh, Edinburgh Innovations, Eureka Institute for Translational Medicine, and Spin-Up Science.