Star-Shaped Magnetic-Plasmonic Au@Fe₃O₄ Nano-Heterostructures for Photothermal Therapy

Abstract

Here, we synthesize a Au@Fe 3 O 4 core@shell system with a highly uniform unprecedented star-like shell morphology with combined plasmonic and magnetic properties. An advanced electron microscopy characterization allows assessing the multifaceted nature of the Au core and its role in the growth of the peculiar epitaxial star-like shell with excellent crystallinity and homogeneity. Magnetometry and magneto-optical spectroscopy revealed a pure magnetite shell, with a superior saturation magnetization compared to similar Au@Fe 3 O 4 heterostructures reported in the literature, which is ascribed to the star-like morphology, as well as to the large thickness of the shell. Of note, Au@Fe 3 O 4 nanostar-loaded cancer cells displayed magnetomechanical stress under a low frequency external alternating magnetic field (few tens of Hz). On the other hand, such a uniform, homogeneous, and thick magnetite shell enables the shift of the plasmonic resonance of the Au core to 640 nm, which is the largest red shift achievable in Au@Fe 3 O 4 homogeneous core@shell systems, prompting application in photothermal therapy and optical imaging in the first biologically transparent window. Preliminary experiments performing irradiation of a stable water suspension of the nanostar and Au@Fe 3 O 4 -loaded cancer cell culture suspension at 658 nm confirmed their optical response and their suitability for photothermal therapy. The outstanding features of the prepared system can be thus potentially exploited as a multifunctional platform for magnetic-plasmonic applications.

Quantitative Analysis of Photothermal Therapy of Tumor Tissue Using Various Gold Nanoparticle Injection Schemes

“…Photothermal therapy is currently being studied from various perspectives. Muzzi et al [ 23 ] proposed the use of particles with an Fe 3 O 4 shell structure on a star-shaped Au core to increase the light conversion efficiency of the light absorption enhancer. Magnetometry and magneto-optical spectroscopy reportedly revealed a pure magnetite shell with excellent saturation magnetization.…”

Revealing the Effect of Photothermal Therapy on Human Breast Cancer Cells: A Combined Study from Mechanical Properties to Membrane HSP70

“…Cancer is still a serious threat to human health, and its high morbidity and mortality rates have promoted researchers to develop more effective cancer therapies. 1 A variety of emerging cancer therapies including immunotherapy, 2 photothermal therapy (PTT), 3,4 and photodynamic therapy (PDT) 5,6 have been developed. PTT is deemed a most promising tumor treatment method due to its advantages of minimally invasive and localized treatment.…”

“…Cancer is still a serious threat to human health, and its high morbidity and mortality rates have promoted researchers to develop more effective cancer therapies . A variety of emerging cancer therapies including immunotherapy, photothermal therapy (PTT), , and photodynamic therapy (PDT) , have been developed. PTT is deemed a most promising tumor treatment method due to its advantages of minimally invasive and localized treatment. − However, PTT also faces many challenges, including but not limited to the fact that the depth of light penetration is insufficient to completely ablate tumors, the systemic distribution of photothermal conversion agents in the body leads to unnecessary heat damage to normal tissues, and the overexpression of heat shock proteins (HSPs) in cancer cells can greatly reduce the therapeutic effect by increasing the resistance of cells to heat .…”

A hydrogel gripper enabling fine movement based on spatiotemporal mineralization

“…In recent years, photothermal materials have attracted a lot of attention for their unique properties of converting light into heat. [23][24][25] Photothermal materials such as metals and their compound, 26,27 organic polymers 28,29 and two-dimensional materials 30 can be loaded into temperature-sensitive hydrogels to prepare light-controlled hydrogel actuators. Compared with other stimuli, light has the merits of remote control, high precision and easy adjustment, and therefore it provides an attractive opportunity for the delicate control of hydrogel actuators.…”