This thesis describes work aimed at developing a new type of therapeutic hybrid nanoparticle which retains the biocompatible surface structure of established polymer nanoparticles but also has a metal nanoparticle interior, which provides the optical properties required for photothermal excitation. This work exploited the expertise in preparation and spectroscopy of metal nanoparticles in Chemistry and Chemical Engineering, and the expertise in biocompatible surfaces, antibody conjugation and tissue culture in Pharmacy.