Biocompatible Triplex Ag@SiO₂@mTiO₂ Core–Shell Nanoparticles for Simultaneous Fluorescence‐SERS Bimodal Imaging and Drug Delivery

Abstract

Herein, we report the synthesis of biocompatible triplex Ag@SiO2@mTiO2 core–shell nanoparticles (NPs) for simultaneous fluorescence‐surface‐enhanced Raman scattering (F‐SERS) bimodal imaging and drug delivery. Stable Raman signals were created by typical SERS tags that were composed of Ag NPs for optical enhancement, a reporter molecule of 4‐mercaptopyridine (4‐Mpy) for a spectroscopic signature, and a silica shell for protection. A further coating of mesoporous titania (mTiO2) on the SERS tags offered high loading capacity for a fluorescence dye (flavin mononucleotide) and an anti‐cancer drug (doxorubicin (DOX)), thereby endowing the material with fluorescence‐imaging and therapeutic functions. The as‐prepared F‐SERS dots exhibited strong fluorescence when excited by light at 460 nm whilst a stable, characteristic 4‐Mpy SERS signal was detected when the excitation wavelength was changed to longer wavelength (632.8 nm), both in solution and after incorporation inside living cells. Their excellent biocompatibility was demonstrated by low cytotoxicity against MCF‐7 cells, even at a high concentration of 100 μg mL−1. In vitro cell cytotoxicity confirmed that DOX‐loaded F‐SERS dots had a comparable or even greater therapeutic effect compared with the free drug, owing to the increased cell‐uptake, which was attributed to the possible endocytosis mechanism of the NPs. To the best of our knowledge, this is the first proof‐of‐concept investigation on a multifunctional nanomedicine that possessed a combined capacity for fast and multiplexed F‐SERS labeling as well as drug‐loading for cancer therapy.

Reporter-Embedded SERS Tags from Gold Nanorod Seeds: Selective Immobilization of Reporter Molecules at the Tip of Nanorods

“…During cell incubation, NPs passed through the cytomembrane and were trapped in the endosome, encountering endogenous small thiol molecules and an acidic environment with a pH of approximately 5, which could promote the dissolution of silver. 47 It was interesting to check the signal stability distinctions of "external" tags and RE tags in these cells. From the dark-field optical imaging of live cells, it was observed that the tags were distributed in cytoplasmic regions after 2 h of incubation, which indicated the uptake of NPs ( Figure 8B).…”

Fluorescent and magnetic dual-responsive coreshell imprinting microspheres strategy for recognition and detection of phycocyanin

“…Cell experiments were carried out for C-MIP and C-NIP as described 42 with necessary modications in the followings. Hela cells were grown as a monolayer in a humidied incubator at 37 C in air-CO 2 (95 : 5) in RPMI-1640 medium that was supplemented with 10% fetal bovine serum.…”

Synthesis of magnetic core-branched Au shell nanostructures and their application in cancer-related miRNA detection via SERS

“…The unique combination of the nanoscale magnetic core and the plasmonic Au shell has opened new avenues in bio-sensing, where two different physical properties of same nanoparticles can be harnessed for detection. Among them one of the most representatives is surface-enhanced Raman scattering (SERS) based assay [8,9], which is known as a powerful tool for ultrasensitive trace detection [10][11][12][13][14][15].…”