Cilia‐Inspired Flexible Arrays for Intelligent Transport of Viscoelastic Microspheres

Abstract

Anisotropic microstructures are widely used by being cleverly designed to achieve important functions. Mammals' respiratory tract is filled with dense cilia that rhythmically swing back and forth in a unidirectional wave to propel mucus and harmful substances out of the lung through larynx. Inspired by the ciliary structure and motion mechanism of the respiratory tract systems, a viscoelastic microsphere transporting strategy based on integration of airway cilium‐like structure and magnetically responsive flexible conical arrays is demonstrated. Under external magnetic fields, the viscoelastic microspheres can be directionally and continuously transported alongside the swing of the cilia‐like arrays that contain magnetic particles. This work provides a promising route for the design of advanced medical applications in directional transport of microspheres, drug delivery systems, ciliary dyskinesia treating, and self‐cleaning without liquid.

Multifunctional Magnetocontrollable Superwettable‐Microcilia Surface for Directional Droplet Manipulation

“…[15,21] Briefly, a series of regularly arranged tapered holes were formed on a commercial polyethylene (PE) sheet by the impact of a mechanical arm on which a stainless steel needle was mounted. [15,21] Briefly, a series of regularly arranged tapered holes were formed on a commercial polyethylene (PE) sheet by the impact of a mechanical arm on which a stainless steel needle was mounted.…”

“…When a magnet is brought close to the superhydrophobic MMA surface, a tiny concave region can be generated. Short microcilia exhibit a weak magnetic response, [15,21] resulting in a smaller curvature of the microcilia, i.e., the tiny concave region formed on the surface, and thus the driving force is too weak to push the water droplets. When the magnetic field moves to the right, the droplet follows the magnetic field to the right; and when the magnetic field moves in the opposite direction, the droplet also moves back under the action of this propulsive force.…”

“…[13] Further, the response of magnetite in a homing pigeons' body to the geomagnetic field assists them in orientation, long-distance migration, and homing. [15] To achieve nondestructive and efficient transportation of droplets, a smart responsive surface with low adhesion is highly sought-after. [15] To achieve nondestructive and efficient transportation of droplets, a smart responsive surface with low adhesion is highly sought-after.…”

Magnetoresponsive Surfaces for Manipulation of Nonmagnetic Liquids: Design and Applications

“…On the one hand, the conical microstructures can be fabricated using facile methods, e.g., by magnetic particle-assisted molding (MPAM). [5,[72][73][74] Using replica molding technique (similar to the fabrication process of the magnetic micropillars shown in Figure 2a), magnetic microneedles with embedded magnetic particles can be obtained. [4,72] Magnetic Microneedles: Figure 4a presents the typical fabrication process of magnetic microneedle surfaces.…”

Tunable and Magnetic Thiol–ene Micropillar Arrays

“…It offers remarkable properties like fast curing where 2 mm thick thiol-ene layer is fully cured by UV dose of approximately 100 J m −2[3] and the ability to tune the mechanical properties of the material from low Young's modulus value of less than 11 MPa [4] to high Young's modulus value of 1750 MPa [2a] by controlling the crosslinking density. [7] Notable applications of magnetic pillars that have been reported include tactile force sensing, [8] liquid flow sensing, [9] mixing in microfluidic devices, [10] mixing of droplets, [11] switchable adhesive surfaces, [5a] cell analysis, [12] directional wetting, [13] real-time manipulation of light, [6] micromanipulation of beads, [14] and droplet transport. [2] Thiol-ene is therefore a promising material for polymer-based functional materials including micropatterned responsive surfaces.…”