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

[Image: see text] 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 FeCl(2) leads to the formation of Fe(3)O(4) nanoparticles. The reduction reaction replaces the nitro group with an amine group, which finally acts as capping agent for the stabilization of the Fe(3)O(4) 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.