2024-03-04 ピッツバーグ大学
＜関連情報＞
化学、流体流れ、力学を統合して、固定された微細構造における三次元（3D）パターンの自発的形成を促進する Integrating chemistry, fluid flow, and mechanics to drive spontaneous formation of three-dimensional (3D) patterns in anchored microstructures
Moslem Moradi, Oleg E. Shklyaev, and Anna C. Balazs
Proceedings of the National Academy of Sciences Published:March 4, 2024
DOI:https://doi.org/10.1073/pnas.2319777121
Significance
Through modeling, we show that enzymatic reactions on flexible microposts in solution inherently generate reaction-convection processes, which provide untapped approaches for regulating the spatiotemporal behavior of soft matter in fluids. Through self-generated fluid flows, the posts form distinct “fingerprints” that characterize the properties of that given system. Each variation in the system’s features leads to the formation of a different fingerprint. Hence, the system constitutes a sensor, allowing specific chemicals to be identified through the formation of specific patterns. The posts also display kaleidoscopic behavior, where one structure controllably morphs into another, enabling one material to perform multiple tasks. The findings reveal how reaction-convection processes involving immersed posts produce a distinctive interplay among chemistry, hydrodynamics and fluid-structure interactions.
Abstract
Enzymatic reactions in solution drive the convection of confined fluids throughout the enclosing chambers and thereby couple the processes of reaction and convection. In these systems, the energy released from the chemical reactions generates a force, which propels the fluids’ spontaneous motion. Here, we use theoretical and computational modeling to determine how reaction-convection can be harnessed to tailor and control the dynamic behavior of soft matter immersed in solution. Our model system encompasses an array of surface-anchored, flexible posts in a millimeter-sized, fluid-filled chamber. Selected posts are coated with enzymes, which react with dissolved chemicals to produce buoyancy-driven fluid flows. We show that these chemically generated flows exert a force on both the coated (active) and passive posts and thus produce regular, self-organized patterns. Due to the specificity of enzymatic reactions, the posts display controllable kaleidoscopic behavior where one regular pattern is smoothly morphed into another with the addition of certain reactants. These spatiotemporal patterns also form “fingerprints” that distinctly characterize the system, reflecting the type of enzymes used, placement of the enzyme-coated posts, height of the chamber, and bending modulus of the elastic posts. The results reveal how reaction-convection provides concepts for designing soft matter that readily switches among multiple morphologies. This behavior enables microfluidic devices to be spontaneously reconfigured for specific applications without construction of new chambers and the fabrication of standalone sensors that operate without extraneous power sources.
