Superparamagnetic Gold Nanoparticles Synthesized on Protein Particle Scaffolds for Cancer Theragnosis.

Cancer theragnosis using a single multimodality agent is the next mainstay of modern cancer diagnosis, treatment, and management, but a clinically feasible agent with in vivo cancer targeting and theragnostic efficacy has not yet been developed. A new type of cancer theragnostic agent is reported, based on gold magnetism that is induced on a cancer-targeting protein particle carrier. Superparamagnetic gold-nanoparticle clusters (named SPAuNCs) are synthesized on a viral capsid particle that is engineered to present peptide ligands targeting a tumor cell receptor (TCR). The potent multimodality of the SPAuNCs is observed, which enables TCR-specific targeting, T -weighted magnetic resonance imaging, and magnetic hyperthermia therapy of both subcutaneous and deep-tissue tumors in live mice under an alternating magnetic field. Furthermore, it is analytically elucidated how the magnetism of the SPAuNCs is sufficiently induced between localized and delocalized spins of Au atoms. In particular, the SPAuNCs show excellent biocompatibility without the problem of in vivo accumulation and holds promising potential as a clinically effective agent for cancer theragnosis.