Bioinspired Magnetic-Responsive Microcolumn Arrays for Active/Passive Antifouling and Droplet Manipulation

Marine biofouling poses safety risks and economic burdens to human marine activities. Researchers have increasingly focused on developing bioinspired antifouling surfaces as sustainable and eco-compatible alternatives to traditional toxic methods. However, their practical applications remain limited by several challenges such as high costs, complex preparation processes, poor durability in harsh marine environments, and unresolved environmental impact concerns regarding material lifecycle and degradation products. Herein, inspired by the oscillation of coral tentacles and the movement of respiratory cilia, a bionic magnetic-responsive microcolumn array (MMA) surface is fabricated through magnetic field-assisted and template methods. The superhydrophobic MMA (SMMA) surface featuring uniform micro/nanostructures is constructed by laser etching. The SMMA surface achieves dual active/passive antifouling through a synergistic strategy of superhydrophobic wettability and dynamic deformation of the microcolumn arrays. Under external magnetic fields, the SMMA surface continuously oscillates, generating a dynamic surface perturbation that mechanically disrupts biofouling adhesion and accumulation of fouling organisms. Meanwhile, its superhydrophobic properties passively reduce the effective contact area between the surface and bacteria, inhibiting bacterial growth and reproduction. Following a 120 h antifouling test, the magnetically actuated SMMA surface exhibits significantly enhanced antibacterial properties over its static counterpart, achieving inhibition rates of 94.08% against <i>P. pantotrophus</i> and 88.29% against <i>B. subtilis</i>. With sensitive magnetic responsiveness and flexible microcolumn bending properties, the SMMA surface produces directional driving forces under moving magnetic field stimulation, enabling rapid, nondestructive, and directional manipulation of multisubstances, including liquid droplets and solid spheres. Furthermore, the SMMA surface possesses outstanding mechanical durability and physical and chemical stability, providing a cost-effective, high-efficiency, and eco-friendly solution for marine antifouling surfaces and emerging applications in biomedical detection, local chemical reactions, and microfluidic control.