Gold Nanorattles with Intense Raman In Silica Nanoparticles (Nano‐IRIS) as Multimodal System for Imaging and Therapy

Abstract Hybrid colloids consisting of silica coated plasmonic core‐shell metal nanoparticles have driven progress in plethora of applications and are under intense investigation in diverse fields of research. In this regard, we have designed a multifunctional nanocomposite consisting of 1,4‐benzenedithiol (BDT) tagged gold nanorattles (Au‐NRT) as core embedded within a solid silica shell with an additional mesoporous silica shell coating forming an “IRIS” like morphology, referred to as Nano‐IRIS. The nanorattle structure with a solid gold octahedron core and porous cubic gold shell serves as an excellent SERS probe due to the presence of intrinsic electromagnetic (EM) hot‐spots. The intelligent design of incorporating a solid SiO₂ layer in the core‐shell Nano‐IRIS structure helped in incorporating two different imaging functionalities, namely SERS and fluorescence‐based bioimaging into a single nanoplatform, thereby imparting a multimodal imaging attribute to Nano‐IRIS. The solid SiO₂ layer not only helped in keeping the Raman reporter intact in the pores of AuNRT but also maintained the distance between the gold surface and the fluorescent drug Doxorubicin (DOX) encapsulated inside the mSiO₂ layer to achieve fluorescence imaging without quenching. Additionally, Nano‐IRIS also emerged as a drug delivery system demonstrating highly efficient concentration dependent chemotherapy via ROS production and oxidative DNA damage.