Gold nanosphere-antibody conjugates for hyperthermal therapeutic applications

Gold nanoparticles can be conjugated with antibodies or other proteins, and the resulting composite particles will selectively attach to various kinds of biological material. Although exploitation of this for staining microscopy specimens is well known, there has recently been interest in attaching gold nanoparticles to live cells for therapeutic reasons. One motivation is that gold nanoparticles display a strong plasmon resonance with light, which can be exploited in principle for an 'in vivo' photothermal therapy. The treatment of cancer by this technique has recently received attention by others, but here we show how gold nanoparticle-based therapies can be developed to target live macrophage cells. We have employed 'active targeting', a scheme in which gold nanoparticles are functionalised with an antibody specific to the target macrophage cell. We describe how to prepare the conjugated particles, demonstrate that they will selectively attach 'in vitro' to their target macrophage cell but not to a non-target cell type and show that their presence renders the target cell susceptible to destruction by a low power laser.