Modeling Propulsion of Soft Magnetic Nanowires.

Area of Science:

• Biomedical Engineering
• Materials Science
• Nanotechnology

Background:

• Remote navigation of artificial nanostructures in fluids is crucial for biomedical applications.
• Fabricating 3D helical nanostructures is challenging.
• 1D soft magnetic nanowires offer a simpler alternative, adopting chiral shapes under rotating magnetic fields.

Purpose of the Study:

• To develop a comprehensive numerical approach for modeling the propulsion of externally actuated soft magnetic nanowires.
• To validate the model against experimental data for composite nanowires.
• To explain previously unexplained propulsion behaviors.

Main Methods:

• A bead-spring model was developed to simulate arbitrary filament geometries and flexibility.
• The model rigorously accounts for intra-filament hydrodynamic interactions.
• Numerical predictions were compared with experimental results for Ni-Ag and Ni-Ag-Au nanowires.

Main Results:

• The bead-spring model accurately predicts the propulsion of composite two-segment (Ni-Ag) nanowires.
• The model successfully explains bidirectional propulsion observed in three-segment (Ni-Ag-Au) nanowires.
• The numerical approach provides a rationalization for complex nanowire behaviors.

Conclusions:

• The developed numerical model is a powerful tool for designing and understanding magnetically actuated soft magnetic nanowires.
• This work facilitates the advancement of nanorobotics for targeted drug delivery and diagnostics.
• The model's ability to explain complex phenomena like bidirectional propulsion enhances the predictability of these nanodevices.