Local mechanical response of cells to the controlled rotation of magnetic nanorods.
The mechanical response of the cytoplasm was investigated by the intracellular implantation of magnetic nanorods and exposure to low-frequency rotatory magnetic fields. Nanorods (Pt-Ni, ∼200 nm diameter) fabricated by electrodeposition in templates of porous alumina with lengths of approximately 2 and 5 µm were inserted into NIH/3T3 fibroblasts and manipulated with a rotational magnetic field. Nanorod rotation was observed only for torques greater than 3.0 × 10(-16) Nm, suggesting a Bingham-type behavior of the cytoplasm. Higher torques produced considerable deformation of the intracellular material. The cell nucleus and cell membrane were significantly deformed by nanorods actuated by 4.5 × 10(-15) Nm torques. Our results demonstrate that nanorods under magnetic fields are an effective tool to mechanically probe the intracellular environment. We envision that our findings may contribute to the noninvasive and direct mechanical characterization of the cytoplasm.
Department of Mechanical and Metallurgical Engineering, Pontificia Universidad Católica de Chile, Vicuña Mackenna, 4860, Macul, Santiago, Chile.
Matias
M
Castillo
Roberto
R
Ebensperger
Denis
D
Wirtz
Magdalena
M
Walczak
Daniel E
DE
Hurtado
Alfredo
A
Celedon
D000537:Aluminum Oxide; D000818:Animals; D002467:Cell Nucleus / Q000378:metabolism*; D003593:Cytoplasm / Q000378:metabolism*; D005347:Fibroblasts / Q000166:cytology / Q000378:metabolism*; D060328:Magnetic Phenomena; D051379:Mice; D041681:NIH 3T3 Cells; D043942:Nanotubes; D016062:Porosity
D000537:Aluminum Oxide
Bingham fluid; cytoplasm mechanics; magnetic nanorods; rotatory magnetic field