Magneto-plasmonic nanostars for image-guided and NIR-triggered drug delivery

Abstract

Smart multifunctional nanoparticles with magnetic and plasmonic properties assembled on a single nanoplatform are promising for various biomedical applications. Owing to their expanding imaging and therapeutic capabilities in response to external stimuli, they have been explored for on-demand drug delivery, image-guided drug delivery, and simultaneous diagnostic and therapeutic (i.e. theranostic) applications. In this study, we engineered nanoparticles with unique morphology consisting of a superparamagnetic iron oxide core and star-shaped plasmonic shell with high-aspect-ratio gold branches. Strong magnetic and near-infrared (NIR)-responsive plasmonic properties of the engineered nanostars enabled multimodal quantitative imaging combining advantageous functions of magnetic resonance imaging (MRI), magnetic particle imaging (MPI), photoacoustic imaging (PAI), and image-guided drug delivery with a tunable drug release capacity. The model drug molecules bound to the core-shell nanostars were released upon NIR illumination due to the heat generation from the core-shell nanostars. Moreover, our simulation analysis showed that the specific design of the core-shell nanostars demonstrated a pronounced multipolar plasmon resonance, which has not been observed in previous reports. The multimodal imaging and NIR-triggered drug release capabilities of the proposed nanoplatform verify their potential for precise and controllable drug release with different applications in personalized medicine.

Recent Advances in Surface-Enhanced Raman Scattering Magnetic Plasmonic Particles for Bioapplications

“…Among various nanoparticles, plasmonic NPs and magnetic NPs are widely used in biological applications, but each have certain drawbacks that can be complimented by the other type of the NPs [ 51 ]. For example, the weakness of magnetic NPs such as toxicity [ 52 , 53 ], aggregation [ 54 , 55 , 56 ], easy corrosion in water [ 52 ] makes it difficult to work well in biological environments [ 52 , 53 , 54 , 55 , 56 ], while Au NPs hardly detect small amounts (giving low signal) of molecules in the mixture by SERS technology [ 57 , 58 ].…”

“…Therefore, they can be used as both SERS substrates and traditional magnetic NPs. Also, the interplay between the magnetic core and the plasmonic shell in the hybrids exhibits a synergistic effect in thermotherapy and bioimaging [ 21 , 51 ]. Some studies have reported on Fe-Au core shell MPPs, where the Au shell reduces the overall magnetic property, but this property is strong enough for MPP to act as a magnetic NP [ 21 , 35 , 51 ].…”

“…Also, the interplay between the magnetic core and the plasmonic shell in the hybrids exhibits a synergistic effect in thermotherapy and bioimaging [ 21 , 51 ]. Some studies have reported on Fe-Au core shell MPPs, where the Au shell reduces the overall magnetic property, but this property is strong enough for MPP to act as a magnetic NP [ 21 , 35 , 51 ]. For example, in Han et al’s study, the saturation magnetization of Fe 3 O 4 NPs is 64.9 emu g −1 ; after the Au shell is coated, the saturation magnetization decreased to 59.2 emu g −1 and it still retains same coercivity (30 Oe) [ 21 ]; Zhou et al showed the saturation magnetization after coating the Au shell of Fe 3 O 4 decreased from 77.3 emu g −1 to 36.8 emu g −1 and 17.5 emu g −1 but maintained the same coercivity (306 Oe) [ 35 ]; both Fe 3 O 4 -Au core shell MPPs still retain magnetic property.…”

“…For example, in Han et al’s study, the saturation magnetization of Fe 3 O 4 NPs is 64.9 emu g −1 ; after the Au shell is coated, the saturation magnetization decreased to 59.2 emu g −1 and it still retains same coercivity (30 Oe) [ 21 ]; Zhou et al showed the saturation magnetization after coating the Au shell of Fe 3 O 4 decreased from 77.3 emu g −1 to 36.8 emu g −1 and 17.5 emu g −1 but maintained the same coercivity (306 Oe) [ 35 ]; both Fe 3 O 4 -Au core shell MPPs still retain magnetic property. On the other hand, the Au shell supplements better heating in magnetic hyperthermia [ 21 ] and Fe-Au core-shell MPPs exhibited a higher transverse relaxivity comparing with Fe 3 O 4 NPs in bioimaging [ 51 ]. Another combination between magnetic and plasmonic is Ag and Fe based on MPPs that are similar with Au-Fe MPPs in sensitive specific detection [ 36 , 38 , 43 , 59 ], better bioimage [ 28 ] and moreover, they show antibacterial synergistic ability [ 60 , 61 ].…”

Nanoplasmonics in High Pressure Environment

“…During the past decade, nanoplasmonics was employed for the production of photovoltaic devices [1][2][3][4][5][6], optical devices [7][8][9][10][11][12][13][14][15], and biosensors [16][17][18][19][20]. Additionally, nanoplasmonics enabled the enhancement of photocatalysis [21][22][23], the luminescence upconversion enhancement [24,25], and the optical tuning of luminescence and upconversion luminescence [26,27].…”