A Remotely Actuated Multifunctional Nitinol–PMMA Smart Biocomposite: Microcellular Foaming, Shape Morphing, and Controlled Drug Release

The fabrication of smart biomaterials that can perform precisely controlled multifunctional tasks in vivo is a significant and challenging goal in therapeutic medicine. Therefore, a remotely actuated, multifunctional smart biocomposite was fabricated herein using Ni-Ti alloy (Nitinol) and poly(methyl methacrylate) (PMMA). The Nitinol-PMMA composite achieved three distinct functions: shape morphing, microcellular foaming, and drug release. Under a noncontact electromagnetic field, the smart biocomposite underwent simultaneous preprogrammed shape morphing due to the heating of Nitinol and microcellular foaming in the carbon dioxide (CO₂)-saturated PMMA. This foaming enhanced the impact strength of the composite by 143% and enabled the controlled release of preloaded agents such as sodium benzoate (NaBz) from the PMMA matrix. The potential of the Nitinol-PMMA composite for vascular clamping was confirmed in an in vitro environment, wherein it exhibited excellent cytocompatibility with NIH 3T3 fibroblasts. The kinetic analysis of NaBz release using the Korsmeyer-Peppas model confirmed that the drug release was governed by a quasi-Fickian mechanism correlated to the porosity of the material. This remotely actuated system that integrates actuation, microbubble control, and customized therapy via tailored drug delivery represents a promising paradigm for the development of minimally invasive medical devices.