Magnetic Nanorods at the Nano-Bio Interface
Magnetic Nanorod Swimmers
When rotated near a surface, magnetic nanorods can demonstrate controllable swimming. Orientation with respect to the surface and rotation angle determine translation trajectory, and rotational frequency determines translation speed. For more information, see Highly Controllable Near-Surface Swimming of Magnetic Janus Nanorods: Applications to Payload Capture and Manipulation.
A Janus nanorod rotational surface swimmer approaches a bead, captures the bead, then continues swimming along.
Magnetic nanorods attached to cell surfaces endable single-cell manipulation via rolling near a solid-liquid boundary.
Adjusting the angle of rotation with respect to the surface enables steering. The upper video shows a real time view of the rotating rod, while the lower video shows a minimum intensity projection of the upper video.
Single Particle Tracking Reveals Effect of Steric Hindrance when Moving Through Biopolymer Matrices
How does size affect how magnetic nanorods move through biopolymer matrices? Using single particle tracking and optical microscopy, we assessed transport differences between large diameter (~250 nm) and small diameter (~20 nm) nanorods undergoing magnetophoresis through a collagen rich matrix. While large diameter rods demonstrated constant velocity motion indicative of severe entanglement with the matrix, small diameter rods exhibited bimodal “fits-and-starts” type motion, suggesting they were moving through pores in the matrix. For more information, see Single Particle Tracking Reveals Biphasic Transport During Nanorod Magnetophoresis Through Extracellular Matrix.
Large diameter rods, stuck in the matrix.
Small diameter rods access pores of the matrix.