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.

Plasmonic Gold Nanorattle Impregnated Chitosan Nanocarrier for Stimulus Responsive Theranostics

“…The intrinsic fluorescence property of DOX was used to assess the uptake efficiency of the nanocarriers. DOX, when embedded inside the pores of AuNRTs with PCM, is expected to show negligible fluorescence because of the strong quenching effect of gold. , However, upon laser irradiation, the AuNRTs generate heat, which melts the PCM causing a stimulus responsive release of DOX from the nanocarriers. The fluorescence of the released DOX within cells on laser exposure was measured using flow cytometry (details in Experimental Section) to monitor the cellular internalization and release process.…”

“…Among the class of metal nanoparticles, Au based nanostructures have achieved a remarkable status in cancer nanomedicine due to its size- and shape-tunable optical properties, strong NIR responsiveness, excellent photothermal conversion efficiencies, and biocompatibility . Moreover, synthesis of novel Au based nanostructures with hollow and porous morphology has further propelled the development of multifunctional systems having both therapeutic and diagnostic or imaging modalities organized into a single theranostic platform. , Simultaneous loading of therapeutic cargo such as drugs, proteins, and genes, and diagnostic agents such as fluorophores and Raman reporters into the pores of such structures have enabled researchers to diagnose or image the diseased site, as well as precisely control the release of the entrapped therapeutic payload at the desired site in response to a specific stimulus. Further, photothermal therapy (PTT) or chemotherapy individually is less efficient in treating tumor cells; however, combining PTT with localized delivery of anticancer drugs may exhibit synergistic cancer cell killing, thus increasing the overall therapeutic efficacy.…”

Achieving enhanced peroxidase-like activity in multimetallic nanorattles

“…This means that molecules can access the surface of the Au cores, inner and outer AgAu shell walls, and the regions within the pores in the NRs. 19,20,43 Although these factors can contribute to the peroxidise-like activity for the NRs and NSs, it is plausible that they do not fully account for the substantial enhancement when compared to NPs.…”

Plasmonic 3-D wrinkled polymeric shrink film-based SERS substrates for pesticide detection on real-world surfaces

“…A few more SERS substrates were made by depositing various plasmonic nanostructures on paper, polymeric film, porous alumina membrane, and 3-D SERS sensing platforms. [13][14][15][16] The signal amplitude of the analyte's Raman fingerprints was significantly increased by these additional fabrications. The practical application of the SERS substrate demonstrates that it is an excellent tool for detection due to its intriguing qualities, including non-destructiveness, non-invasiveness, usability, affordability, ultra-sensitivity, rapidity, multiplexing capability, portability, etc.…”