Porous Hollow Gold Nanoparticles for Cancer SERS Imaging

Surface enhanced Raman spectroscopy (SERS) is a promising molecular imaging modality capable of simultaneously detecting multiple molecular biomarkers. With the biocompatibility and functionalizability of Au, Au-nanoparticle based Raman tags possess the potential for in vivo SERS cancer biomarker detection. Here, we report the large scale synthesis of a new type of Au nanoparticles, Porous Hollow Au Nanoparticles (PHAuNPs), and demonstrate their potential application as SERS imaging tags. PHAuNPs feature a sub-20 nm porous shell and a 50 nm void core. Such unique morphology enables them to strongly absorb and scatter near infrared lights due to the surface plasmon resonant effect of Au. This makes them particularly suitable for in vivo applications, where NIR wavelengths are considered as a ‘clear window’ for deeper penetration of light. The construction and characterization of PHAuNP-based Raman nanotag, including attachment of Raman dye, pegylation and their stability, are described. Cytotoxicity of Raman nanotags are tested using the radioactive [3H]thymidine incorporation method. The results show that pegylated Raman nanotags are stable and non-toxic and can potentially be used for in vivo applications.