α,ε-Hybrid Peptide-Stabilized Magnetic Nanoparticle-Coated Paper-Based Actuators

The development of α,ε-hybrid peptide-stabilized magnetic nanoparticles and their application to fabricate a paper-based actuator has been reported. From single-crystal diffraction analysis, the nitropeptide 2 has an extended structure with a trans geometry. The one-pot in situ multiple oxidation-reduction reaction of a synthetic nitropeptide solution in ammonium hydroxide and FeCl₂ leads to the formation of Fe₃O₄ nanoparticles. The reduction reaction replaces the nitro group with an amine group, which finally acts as capping agent for the stabilization of the Fe₃O₄ nanoparticles. Paper-based soft magneto machines with multivariant actuation modes such as contraction-expansion, bending, and uplifting locomotion have been studied. The device has potential as controllable paper-based soft robots.