Magnetically amplified photothermal therapies and multimodal imaging with magneto-plasmonic nanodomes. (September 2018)

• Record Type: Journal Article
• Authors: Li, Zhi; Aranda-Ramos, Antonio; Güell-Grau, Pau; Tajada, José Luis; Pou-Macayo, Laia; Lope Piedrafita, Silvia; Pi, Francesc; G. Roca, Alejandro; Baró, María Dolors; Sort, Jordi; Nogués, Carme; Nogués, Josep; Sepúlveda, Borja
• Is Part Of: Applied materials today. Volume 12(2018)
• Page Start: 430
• Page End: 440
• Publication Date: 2018-09
• Subjects: Magneto-plasmonic nanoparticles -- Photothermal therapies -- Magnetic manipulation -- Contrast agents; Materials science -- Periodicals; Materials -- Research -- Periodicals; 620.1105
• DOI: 10.1016/j.apmt.2018.07.008
• Languages: English
• ISSNs: 2352-9407

Abstract

Graphical abstract: Highlights: MP nanodomes show magnetic dipoles equivalent to 10 3 superparamagnetic iron oxide nanoparticles. They show similar photothermal conversion efficiency (65%) as the best plasmonic nanoheaters. Magnetic concentration enables large enhancement of the optical heating efficiency. MP nanodomes are high contrast agents for NMR ( T 2 ), X-ray absorption, and fluorescence imaging. Magnetic enrichment at the illumination region enables near 100% efficiency in photothermal treatments in vitro. Abstract: Nanotherapies require new ways for controlling and improving the delivery of the therapeutic agents to the site of action to maximize their efficacy and minimize the side effects. This control is particularly relevant in photothermal treatments to reduce the required light intensity and amount of injected nanoparticles, and to minimize necrotic cell deaths. Here we present a novel concept for multifunctional nanobiomedical agents: magneto-plasmonic (MP) nanodomes for magnetically guided and amplified photothermal therapies and as contrast agents for multimodal imaging. The MP nanodomes are composed of a Fe/Au bilayer semi-shell deposited on a 100 nm diameter fluorescent polystyrene nanosphere, which gather a unique combination of straightforward functionalization, high colloidal stability, very strong ferromagnetic behavior and intense optical absorption efficiency in the near infrared. We show that the photothermal conversion efficiency of the Fe/Au nanodomes with high Fe ratios is substantially larger than pure plasmonic Au nanodomes and the state-of-art plasmonic nanoheaters, i.e. Au nanorods and nanoshells, by merging strong optical absorption, minimized scattering and low optical anisotropy. Remarkably, the effective magnetophoretic concentration of the Fe/Au nanodomes at the illumination region enables large local increase of the optically induced temperature rise. The Fe semishell also provides very intense T 2 contrast in nuclear magnetic resonance, which is at least 15-fold larger per particle than commercial iron oxide contrast agents. Moreover, the fluorescent polystyrene nanosphere and the Au semishell integrate valuable fluorescent and X-ray contrasts, respectively, which we have used to assess the nanodomes internalization by cancer cells. The MP nanodomes are nontoxic to cells even in the case of magnetophoretic local enrichment with initially high particle concentration (100 μg/mL). Remarkably, we demonstrate amplified local photothermal treatments by the magnetic enrichment of the nanodomes at the illumination region, which enables reaching nearly 100% reduction of cell viability with low particle concentration (10 μg/mL) and mild NIR laser intensity (5 W/cm 2 ). These results highlight the high potential of MP nanodomes for magnetically guided and amplified photothermal therapies.