Anisotropic metal nanoparticles have been successful used in a wide range of biomedical applications, such as diagnostics and therapy, because of their unique optical and electronic properties. Even though there is a wide range of morphologies synthetically available, the understanding of the mechanism behind the anisotropic growth of the nanoparticles is still incomplete. Regarding their application in diagnostics, metallic nanoparticle-based biosensors are facing new challenges, such as the discovery of novel circulating cancer biomarkers (e.g. cell-free DNA), which require sensitivities that cannot be achieved by traditional approaches. The research of this thesis covers current challenges in three specific areas found in the interface between bio- and nanoscience. (1) Colloidal synthesis, where a novel synthesis of gold nanorods (AuNRs) has been developed by the addition of Hofmeister salts into the growth solution. The thorough characterization of the surfactant micelles in the growth solution provided a better understanding of the role of the surfactant as symmetry breaking component in the anisotropic growth. (2) Diagnostics and disease prevention, where two new metal nanoparticle-based biosensors have been developed. The first one exploits the control of a photoresponsive fluid over the dimensions of anisotropic gold nanoparticles for UV exposure sensing and erythema prediction, where the nanoparticles are synthesized and used for sensing purpose at the same time. The second one is a AuNR-based biosensor for circulating cell-free DNA with inverse sensitivity, i.e. the lower the analyte concentration, the higher the response intensity. (3) Bio-inspired materials, where a hybrid system made of AuNR-DNA has been designed to study the sequence-specific binding between transcription factors and DNA. This system has been further expanded to build a versatile multi-logic gate platform, capable of performing six different logic operations. Finally, the use of alternative plasmonic nanomaterials for sensing and bio-inspired materials has also been explored
