Rose-Inspired Micro-device with Variable Stiffness for Remotely Controlled Release of Objects in Robotics

In this work, we present a biomimetic device, with micro-prickle-like hooks capable of variable stiffness remotely controlled by a laser. We designed artificial prickles taking inspiration from the geometry of the natural prickles of the climbers Rosa arvensis ‘Splendens’, which has a peculiar downward orientation of the tip. We fabricated artificial arrays with micro-prickles using a combination of different microfabrication techniques, including direct laser lithography (DLL), micro-moulding of PDMS and thermoplastic polycaprolactone polymer (PCL) with incorporated rod-shaped gold nanoparticles (PCL@Au NPs). Due to the plasmonic effect, Au NPs heat upon laser irradiation and thus induce a controlled softening of the PCL polymeric matrix. Thermal characterization of the device under different laser intensities was performed using a dedicated setup and it provided suitable output for remotely controlling the device. The developed micro-device can hook and release a weight of 2Â g varying the prickle stiffness by using a laser power with on-off cycles. This biomimetic approach permits to gain new insights for developing innovative intelligent systems in robotics, such as controllable adhesion-based grippers for micromanipulation.