Magnetite-Gold nanohybrids as ideal all-in-one platforms for theranostics

Abstract

High-quality, 25 nm octahedral-shaped Fe3O4 magnetite nanocrystals are epitaxially grown on 9 nm Au seed nanoparticles using a modified wet-chemical synthesis. These Fe3O4-Au Janus nanoparticles exhibit bulk-like magnetic properties. Due to their high magnetization and octahedral shape, the hybrids show superior in vitro and in vivo T2 relaxivity for magnetic resonance imaging as compared to other types of Fe3O4-Au hybrids and commercial contrast agents. The nanoparticles provide two functional surfaces for theranostic applications. For the first time, Fe3O4-Au hybrids are conjugated with two fluorescent dyes or the combination of drug and dye allowing the simultaneous tracking of the nanoparticle vehicle and the drug cargo in vitro and in vivo. The delivery to tumors and payload release are demonstrated in real time by intravital microscopy. Replacing the dyes by cell-specific molecules and drugs makes the Fe3O4-Au hybrids a unique all-in-one platform for theranostics.

Size-selected Fe3O4–Au hybrid nanoparticles for improved magnetism-based theranostics

“…The high contrast properties of 25 nm Fe 3 O 4 –Au hybrid NPs for in vitro MRI in 4T1 mouse breast adenocarcinoma cells have been recently demonstrated [ 84 ]. In summary, a r 2 value of 276.9 mM −1 ·s −1 was obtained after 24 h of NP incubation with cell culture.…”

“…Fe 3 O 4 –Au hybrid NPs with presynthesized Au seeds (MNP-25 and MNP-44) were grown by thermal decomposition of Fe(CO) 5 in the presence of Au NPs following a modified protocol [ 84 , 99 ]. A mixture of 1 mL oleic acid and 20 mL solvent (phenyl ether for sample MNP-25 or benzyl ether for sample MNP-44) was heated up to 120 °C under argon atmosphere and kept at this temperature for 30 min.…”

Latest advances in combining gold nanomaterials with physical stimuli towards new responsive therapeutic and diagnostic strategies

“…However, applications of gold clusters for therapeutic hyperthermia under alternative magnetic force exposure have not been developed yet [62]. On the other hand, alloy iron oxide-gold nanoparticles have been investigated as contrast agents for MRI by exploiting the magnetic properties of iron oxide [63][64][65][66][67]. Magnetic alloy AuNMs and their biomedical applications have been comprehensively described in a recent review [68].…”

<p>Improving Cell Penetration of Gold Nanorods by Using an Amphipathic Arginine Rich Peptide</p>

“…Global progress in nanotechnology has led to notable developments in nanomedicine, including new diagnostic systems, drug delivery methods, and a variety of disease treatments. [1][2][3][4][5][6] One such advancement is represented by gold nanoparticles, which have a large surface-to-size ratio and are highly reactive. 7,8 These properties allow gold nanoparticle functionalization with synthetic molecules or biomolecules (eg, antibodies, polymers, drugs, DNA, RNA, and peptides), in addition to facilitating biological barrier permeation and, consequently, access to different sites of interest.…”