Superparamagnetic microrobots: fabrication by two-photon polymerization and biocompatibility
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This work presents the fabrication and controlled actuation of swimming microrobots made of a magnetic polymer composite (MPC) consisting of 11-nm-diameter magnetite (Fe3O4) nanoparticles and photocurable resin (SU-8). Two-photon polymerization (TPP) is used to fabricate the magnetic microstructures. The material properties and the cytotoxicity of the MPC with different nanoparticle concentrations are characterized. The live/dead staining tests indicate that MPC samples with varied concentrations, up to 10 vol.%, have negligible cytotoxicity after 24 h incubation. Fabrication parameters of MPC with up to 4 vol.% were investigated. We demonstrate that the helical microdevices made of 2 vol.% MPC were capable of performing corkscrew motion in water applying weak uniform rotating magnetic fields.
KeywordsSuperparamagnetic nanocomposite Microrobots Magnetic actuation Cytotoxicity
The authors thank Eszter Barthazy and Elisabeth Müller (EMEZ at ETH Zurich) for the TEM-images, the technical support from the FIRST lab at ETH Zurich. Funding for this research is provided by Swiss National Science Foundation (SNSF), project number 130069 and the ETH Zurich (TH-28 06–3).
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