Fig. 2: Understanding remora’s adhesion to soft substrates through biomimicry.
From: Mechanical underwater adhesive devices for soft substrates
a, Modelling remora adhesive disc mimicries contacting stomach tissue: a benchmark one-piece disc (left), a furled multicompartmental disc (middle) and an unfurled multicompartmental disc (right). Scale bar, 5 mm. b, Relative vacuum Vr (expelled water volume relative to theoretical maximum volume AInitial) achieved by disc mimicries post-tissue contact. c, Illustration of MUSAS delivery: (1) release, (2) adhesion and (3) safe passage. d, Schematic of the optimal MUSAS, inspired by R. albescens. Scale bar, 5 mm. e, MUSAS compacts into a size 000 capsule, with elastomeric fabrication flexibility (transparent, Ecoflex 0030; pink, Zhermack Elite Double 8). Scale bar, 1 cm. f, Active mechanical interlocking of MUSAS via SMA lamellae. Left: active lamella deformation (bottom) mimicking remora’s interlocking (top). Middle: temperature-induced SMA lamella erection. Right: modelling stress and martensite volume fraction during lamella erection. Scale bar, 1 mm. g, Designs (I–VI) tested to dissect the physico-mechanical roles of disc components, including the lamellae, multicompartment adhesive disk, backbone, disk lip curvature, and disk elastomer compatibility. h, Adhesion performance across different lip thicknesses, where Ws and We denote the lip thickness at the start and end of the disk lip, respectively. i, Contribution of disc components to adhesion. j,k, Adhesion performance (j) and shear sliding measuring retained adhesion post-plateau (k; also see Extended Data Fig. 2) of designs with various lamella orientations and row numbers, mimicking three representative remora species. It is noted that the parallel-eight-rows design (j) is the benchmark E-Curve tested in i. n = 5 devices per design were tested in h–k. For h, boxes represent the median and the Q1 and Q3 quartiles, and whiskers represent the minimum and maximum. For i and j, the dashed and dotted lines represent the median and the Q1 and Q3 quartiles, respectively. For k, the error bars represent mean ± s.d. One-way (i) and two-way (j,k) analysis of variance with Šídák multiple comparison test were used to compare different designs. Statistical significance is indicated as follows: NS, non-significant, *P ≤ 0.05, **P ≤ 0.01, ***P ≤ 0.001, ****P ≤ 0.0001.
