Probing in-mouth texture perception with a biomimetic tongue

Abstract

An experimental biomimetic tongue-palate system has been developed to probe human in-mouth texture perception. Model tongues are made from soft elastomers patterned with fibrillar structures analogue to human filiform papillae. The palate is represented by a rigid flat plate parallel to the plane of the tongue. To probe the behavior under physiological flow conditions, deflections of model papillae are measured using a novel fluorescent imaging technique enabling sub-micrometer resolution of the displacements. Using optically transparent newtonian liquids under steady shear flow, we show that deformations of the papillae allow determining their viscosity from 1 Pa.s down to the viscosity of water of 1 mPa.s, in full quantitative agreement with a recently proposed model [Lauga et al., Frontiers in Physics, 2016, 4, 35]. The technique is further validated for a shear-thinning and optically opaque dairy system.

3D Biomimetic Tongue-Emulating Surfaces for Tribological Applications

“… 37 Nevertheless, whether or not the arrangements and density of papillae influence their mechanosensing efficiency remain poorly understood. In general, a regular square grid arrangement 17 , 38 of papillae has been used as a basic model of papillae distribution in literature. However, as seen in Figure 1 , the distribution of papillae is clearly complex and irregular.…”

Collective stiffening of soft hair assemblies

“…In a previous work [18], we have shown that deflections of an isolated elastomeric pillar submitted to a shear flow are proportional to the local shear stresses. In the context of in-mouth texture perception, we concluded that filiform papillae could act as sensitive stress sensors.…”

“…The deflection of an isolated pillar in a viscous flow has been successfully predicted using elastohydrodynamics [13,14,18]. In biological systems, however, hairs are usually densely packed and their mechanical behavior is likely subjected to hydrodynamic interactions.…”

“…We used a minimal biomimetic setup sketched in Fig. 1(a) (see [18] and Supplemental Material [22]). Briefly, it consists in mimicking soft hair assemblies with a pool made of an elastomer, whose bottom is decorated with cylindrical pillars of diameter 2a = 100 μm and length L = 435 ± 7 μm.…”

“…Their dynamic viscosities η were measured with the rheometer operating in a plate-plate geometry. Pillar tip deflections δ were measured [18] by correlating images of a pillar in its deformed state with a reference image where the pillar is at rest [Fig. 1(c)].…”