A multiphysics model of magnetic hydrogel under a moving magnet for targeted drug delivery

Abstract

A remarkable characteristics of magnetic hydrogel is its ability to dramatically alter its morphology and location in a remote way. Herein, a three-dimensional (3D) multiphysics model is presented to study the motion and deformation of the drug-loaded magnetic hydrogel in a moving fluid under an varying magnetic field created by a moving magnet. The magneto-chemo-hydro-mechanical model allows for nonlinear finite deformation, and the governing equations are formulated by balances of mass and forces. The constitutive relations are achieved via the second law of thermodynamics. In particular, the fluid-structure interaction is considered between the magnetic hydrogel and its surrounding fluid. After validation with theoretical works, the movable and deformable behaviors of the magnetic hydrogel are then studied under varying magnetic velocity, hydrogel radius, magnetic field strength, and fluid flow velocity. Results show that the slower moving magnet, the larger hydrogel radius and the flow velocity can shorten the time for the hydrogel to reach the channel outlet. In addition, the magnetic targeting system is obtained for transporting the drug-loaded hydrogel to the specific site through controlling the magnet velocity and the maximum magnetic field strength. The present multiphysics model may provide theoretical guidance in design and optimization of magnetic hydrogel-based drug targeting system.