Year: 2026
Type: preprint
Abstract: Capsules are attractive platforms for microrobot delivery, combining structural simplicity with protected delivery and rapid release remains challenging. Inspired by the latched spring mechanism of Impatiens balsamina seed dispersal, a magnetothermally triggered capsule integrates a phase-change hydrogel latch, a monostable cover that serves as an elastic spring, and a payload-carrying base. Mechanical analysis guides the cover design to avoid bistability after assembly and premature hydrogel latch rupture before triggering. During transport, the hydrogel constrains the inverted cover. Under an alternating magnetic field, Fe3O4-mediated heating softens the hydrogel and induces cohesive failure, releasing stored energy to drive capsule opening and microrobot ejection. The capsule opens within 50 ms after hydrogel softening and ejects microrobots at an estimated initial velocity of 1.0 m/s. Demonstrations on a three-dimensional platform and ex vivo porcine stomach establish protected delivery, target-site opening, and post-release actuation.
Source: arXiv (Cornell University)
Language: English
Topic: Micro and Nano Robotics
Subfield: Condensed Matter Physics
Field: Physics and Astronomy
Domain: Physical Sciences
Open Access status: green
OpenAlex ID: W7214939224