title: Superparamagnetic microrobots: fabrication by two-photon polymerization and biocompatibility.
abstract: 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.
authors.affiliation: Micro and Nano Systems, ETH Zurich, Zurich, Switzerland.
authors.forename: Marcel
authors.initials: M
authors.lastname: Suter
authors.forename: Li
authors.initials: L
authors.lastname: Zhang
authors.forename: Erdem C
authors.initials: EC
authors.lastname: Siringil
authors.forename: Christian
authors.initials: C
authors.lastname: Peters
authors.forename: Tessa
authors.initials: T
authors.lastname: Luehmann
authors.forename: Olgac
authors.initials: O
authors.lastname: Ergeneman
authors.forename: Kathrin E
authors.initials: KE
authors.lastname: Peyer
authors.forename: Bradley J
authors.initials: BJ
authors.lastname: Nelson
authors.forename: Christofer
authors.initials: C
authors.lastname: Hierold
mesh_terms: D002470:Cell Survival / Q000187:drug effects; D004852:Epoxy Compounds / Q000737:chemistry; D058185:Magnetite Nanoparticles / Q000737:chemistry* / Q000633:toxicity*; D008422:Materials Testing; D055616:Microtechnology / Q000379:methods*; D017785:Photons; D058105:Polymerization; D011108:Polymers / Q000737:chemistry; D012371:Robotics
chemical_list: D004852:Epoxy Compounds; D058185:Magnetite Nanoparticles; D011108:Polymers; C520895:SU-8 compound