Laser-Ablative Synthesis of Silicon–Iron Composite Nanoparticles for Theranostic Applications

Abstract

The combination of photothermal and magnetic functionalities in one biocompatible nanoformulation forms an attractive basis for developing multifunctional agents for biomedical theranostics. Here, we report the fabrication of silicon–iron (Si-Fe) composite nanoparticles (NPs) for theranostic applications by using a method of femtosecond laser ablation in acetone from a mixed target combining silicon and iron. The NPs were then transferred to water for subsequent biological use. From structural analyses, it was shown that the formed Si-Fe NPs have a spherical shape and sizes ranging from 5 to 150 nm, with the presence of two characteristic maxima around 20 nm and 90 nm in the size distribution. They are mostly composed of silicon with the presence of a significant iron silicide content and iron oxide inclusions. Our studies also show that the NPs exhibit magnetic properties due to the presence of iron ions in their composition, which makes the formation of contrast in magnetic resonance imaging (MRI) possible, as it is verified by magnetic resonance relaxometry at the proton resonance frequency. In addition, the Si-Fe NPs are characterized by strong optical absorption in the window of relative transparency of bio-tissue (650–950 nm). Benefiting from such absorption, the Si-Fe NPs provide strong photoheating in their aqueous suspensions under continuous wave laser excitation at 808 nm. The NP-induced photoheating is described by a photothermal conversion efficiency of 33–42%, which is approximately 3.0–3.3 times larger than that for pure laser-synthesized Si NPs, and it is explained by the presence of iron silicide in the NP composition. Combining the strong photothermal effect and MRI functionality, the synthesized Si-Fe NPs promise a major advancement of modalities for cancer theranostics, including MRI-guided photothermal therapy and surgery.

Electrospun Fenoprofen/Polycaprolactone @ Tranexamic Acid/Hydroxyapatite Nanofibers as Orthopedic Hemostasis Dressings

“…In this nano era, nanotechnologies and the related nanomaterials have demonstrated their powers in almost all the applied scientific fields [6,7], including numerous biomedical treatments [8][9][10][11][12][13][14]. Those nano-related elements are bringing out revolutionary changes in the field of orthopedics for orthopedic surgery.…”

Editorial: Special Issue “Laser Synthesis and Processing of Nanostructured Materials”

“…Special Issue was focused on recent trends in the fabrication of functional nanostructures, nanomaterials and nanotextured surfaces using laser radiation. The resulting content of this Special Issue comprising 10 original papers reflects the diversity of the developing nanofabrication strategies that utilize pulsed laser radiation, including pulsed laser ablation in liquid (PLAL) for nanomaterial generation [ 1 , 2 , 3 , 4 ], pulsed laser deposition (PLD) of functional coatings [ 5 ], laser-induced forward transfer (LIFT) [ 6 ], laser sintering [ 7 ], pulsed laser surface nanotexturing [ 8 ] and direct laser writing in transparent media [ 9 , 10 ].…”

“…A perfect example of expanded functionality originating from a combination of different materials within unified nanoparticles was given by Bubnov et al, who reported on PLAL-based synthesis of silicon–iron (Si-Fe) nanohybrids [ 1 ]. In particular, the authors demonstrated that such a material combination is favorable for the spectrally strong broadband light-to-heat conversion performance of the produced nanoparticles, while the presence of Fe atoms provides them with magnetic properties.…”