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Shark skin exhibits a well-defined multilayered architecture, consisting of three-dimensional denticles and an underlying dermal layer, which contributes to its passive drag reduction. However, the active drag reduction mechanisms of this interface remain largely unexplored. In this study, the Marangoni effect potentially arising from the active secretion of mucus on shark skin is investigated. A 3D-printed swimming robot with a porous substrate and a biomimetic shark denticle structure is developed. By introducing surfactants into the porous substrate and adjusting denticle arrangements, on-demand propulsion and controlled swimming trajectories are achieved. A superhydrophobic surface is fabricated on the swimming robot, which reduces water resistance and enhances propulsion. Moreover, denticles with a 30° attack angle demonstrate optimal propulsion performance in both Marangoni-driven hydrodynamics and aerodynamics. This study suggests that the secretion of mucus on shark skin may facilitate active drag reduction via the Marangoni effect, offering novel insights into the biomimetic structural design of autonomous swimming robots.
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http://dx.doi.org/10.3390/biomimetics10080479 | DOI Listing |
ACS Appl Mater Interfaces
September 2025
College of Metrology Measurement and Instrument, China Jiliang University, Hangzhou 310018, China.
During the long course of evolution, fish have developed complex skin structures to adapt to the dynamic aquatic environment. These skin features not only reflect optimal adaptation to the aquatic environment but also play a key role in effectively reducing fluid drag and improving swimming efficiency, to reveal the intrinsic connection between the complex skin structure of fish and drag reduction performance and to provide new design ideas for the drag reduction surface of underwater vehicles. Based on the different drag reduction characteristics of fish skin structures, this paper divides existing biomimetic drag reduction technologies into three categories: riblet drag reduction, flexible drag reduction, and composite drag reduction.
View Article and Find Full Text PDFBioinspir Biomim
September 2025
Mechanical Engineering, University of California Berkeley, 6177 Etcheverry Hall, Berkeley, California, 94720, UNITED STATES.
Riblets inspired by natural shark skin denticles are widely recognized for their drag-reducing performance. Although previous research has predominantly focused on two-dimensional riblet geometries, three-dimensional topographies remain underexplored due to the complex architecture of denticle-inspired surfaces. Natural riblet arrays, comprising thousands of interconnected denticles, pose challenges in terms of parameterization, simulation, and fabrication.
View Article and Find Full Text PDFACS Appl Mater Interfaces
August 2025
School of Microelectronics, Shanghai University, Shanghai 201800, China.
Dural closure with a replacement is a crucial procedure in neurosurgery. Conventional dura mater substitutes derived from collagen often exhibit low mechanical strength and strong adhesion to the brain tissue, leading to complications such as cerebrospinal fluid leakage, brain adhesion, and intracranial infection. Silk fibroin extracted from silkworms () can be used as an ideal substitute for dura mater with excellent histocompatibility, degradability, and tunable mechanical strength.
View Article and Find Full Text PDFBiomimetics (Basel)
July 2025
CAS Key Laboratory of Bio-Inspired Materials and Interfacial Science, Technical Institute of Physics and Chemistry, Chinese Academy of Sciences, Beijing 100190, China.
Shark skin exhibits a well-defined multilayered architecture, consisting of three-dimensional denticles and an underlying dermal layer, which contributes to its passive drag reduction. However, the active drag reduction mechanisms of this interface remain largely unexplored. In this study, the Marangoni effect potentially arising from the active secretion of mucus on shark skin is investigated.
View Article and Find Full Text PDFIntegr Comp Biol
August 2025
Department of Biological Sciences, Florida Atlantic University, Boca Raton, FL 33431, USA.
Shark skin is covered superficially by the crowns of dermal denticles, tooth-shaped scales, whose bases are embedded into the dermis. Denticles provide sharks with functional benefits, including protection during mating and enhanced drag reduction during high-speed swimming. In a few species, research showed that denticle morphology changes as a shark matures and differs between sexes, especially in regions where males bite females during mating.
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