Directional Particle Delivery Using Freestanding BTO/LSMO Magnetoelectric Scrolls.

Freestanding magnetoelectric films fabricated utilizing water-soluble sacrificial layers exhibit significant potential for transformative applications in next-generation technologies and biomedicine. This study presents the fabrication, comprehensive characterization, and multifunctional analysis of BaTiO3 (BTO) and La0.7Sr0.3MnO3 (LSMO) multilayer films. These heterostructures undergo spontaneous morphological transformation into three-dimensional scrolls (3D) or spring-like architectures driven by stress-induced curling mechanisms. A programmable transition from planar, two-dimensional (2D) configurations to self-rolled, three-dimensional magnetoelectric scrolls with tunable diameters is achieved via precise modulation of the relative thicknesses of the BTO and LSMO layers. The resulting freestanding magnetoelectric scrolls exhibit dual functionalities: effective encapsulation of drug simulants, as exemplified by polystyrene microparticles, and the capacity for directed movement at room temperature under ultra-low magnetic field actuation. The fundamental mechanism underpinning this controlled self-assembly arises from the synergistic interaction between strain relaxation after sacrificial layer dissolution and the intrinsic ferroelastic properties of BTO. Concurrently, the room-temperature ferromagnetism inherent to LSMO enables real-time magnetic modulation of scroll deformation dynamics. Biocompatibility assessment via hemolysis assays confirmed the cytocompatibility of these magnetoelectric scrolls. This integrated architecture exhibits considerable potential for multifunctional biomedical applications, including targeted therapeutic delivery, bladder lavage, and thrombus removal. These findings establish freestanding BTO/LSMO magnetoelectric scrolls as promising candidates for the development of next-generation intelligent, stimuli-responsive, and magnetically navigable biomaterials.