<figure><img src="image_1.png" /></figure>

HAL
open science

# Toward a more realistic 3D biomimetic soft robotic tongue to investigate oral processing of semi-solid foods

Alejandro Avila-Sierra, Yurixy Bugarin-Castillo, Juluan Voisin, Vincent

Mathieu, Marco Ramaioli

► To cite this version:

Alejandro Avila-Sierra, Yurixy Bugarin-Castillo, Juluan Voisin, Vincent Mathieu, Marco Ramaioli. Toward a more realistic 3D biomimetic soft robotic tongue to investigate oral processing of semi-solid foods. Living Machines 2023, Jul 2023, Genoa, Italy. hal-04521277

HAL Id: hal-04521277

https://hal.science/hal-04521277

Submitted on 26 Mar 2024

HAL is a multi-disciplinary open access
archive for the deposit and dissemination of sci-
entific research documents, whether they are pub-
lished or not. The documents may come from
teaching and research institutions in France or
abroad, or from public or private research centers.

L'archive ouverte pluridisciplinaire HAL, est
destinée au dépôt et à la diffusion de documents
scientifiques de niveau recherche, publiés ou non,
émanant des établissements d'enseignement et de
recherche français ou étrangers, des laboratoires
publics ou privés.

<figure><img src="image_2.png" /></figure>

Distributed under a Creative Commons Attribution 4.0 International License
# Toward a more realistic 3D biomimetic soft robotic tongue to investigate oral processing of semi-solid foods

Alejandro Avila-Sierra, Yurixy Bugarin-Castillo, Juluan Voisin, Vincent Mathieu, Marco Ramaioli

## ► To cite this version:

Alejandro Avila-Sierra, Yurixy Bugarin-Castillo, Juluan Voisin, Vincent Mathieu, Marco Ramaioli. Toward a more realistic 3D biomimetic soft robotic tongue to investigate oral processing of semi-solid foods. Living Machines 2023, Jul 2023, Genoa, Italy. hal-04521277

HAL Id: hal-04521277

https://hal.science/hal-04521277v1

Submitted on 26 Mar 2024

HAL is a multi-disciplinary open access archive for the deposit and dissemination of scientific research documents, whether they are published or not. The documents may come from teaching and research institutions in France or abroad, or from public or private research centers.

L'archive ouverte pluridisciplinaire HAL, est destinée au dépôt et à la diffusion de documents scientifiques de niveau recherche, publiés ou non, émanant des établissements d'enseignement et de recherche français ou étrangers, des laboratoires publics ou privés.

<figure><img src="image_1.png" /></figure>
<figure><img src="image_3.png" /></figure>

<figure><img src="image_4.png" /></figure>

<figure><img src="image_5.png" /></figure>

<figure><img src="image_6.png" /></figure>

# Toward a more realistic 3D biomimetic soft robotic tongue to investigate oral processing of semi-solid foods

Avila-Sierra, A.; Bugarin-Castillo, Y.; Voisin, J.; Mathieu, V.; Ramaioli, M.

UMR SayFood, U.Paris - Saclay, INRAE, AgroParisTech, Palaiseau, France

## Introduction

Current *in vitro* experiments reproducing food oral processing lack complete accuracy in capturing the complexity of the oral anatomy and physiological biomechanics of the human tongue.

While the importance of rheology and tribology of soft food is widely recognized [1-4], there is no system yet capable of realistically simulating the dynamic changes that occur in the human oral cavity when semi-solid foods are ingested.

The tongue, a soft tissue comprising micro-asperities known as papillae, contributes to modulate oral friction and lubrication, aided by tongue wettability.

These factors play a crucial role in controlling biophysical functions like sensory perception and food transport [5], affecting the amount of residue left in mouth after swallowing.

## Aim

It is crucial to develop a system that accurately mimics the intricate architectural, chemical, and mechanical features, as well as the complex motions of the human tongue. Such a system is essential for **gaining a comprehensive and quantitative understanding of how fluids and foods interact with the surfaces of the oral cavity**.

## Materials & Methods

<figure><img src="image_7.png" /></figure>

<figure><img src="image_8.png" /><figcaption>**Figure 1.** BSRT manufacturing (A) and schematics of the pneumatic system (B) used to fabricate/control the soft robotic actuator. Manufacturing: (1) pouring of the Ecoflex® mixture (containing Span 80 (0.5 wt %) to modulate wettability[6]) into the moulds, (2) adding the surface texturing mould, (3) de-moulding of the cured actuator and its base, and (4) final gluing of both parts.</figcaption></figure>

<figure><img src="image_9.png" /></figure>

<figure><img src="image_10.png" /><figcaption>**Figure 2.** 3D Image (A) showcases the CAD model of the artificial papillae based on average in vivo data [5]. This model includes a surface area of 10 x 10 mm, incorporating a randomized distribution. Moreover, (B) features a snapshot of the model surface pattern applied to the upper surface of the soft actuator. This image was captured using a digital camera, showcasing the soft robotic tongue surface at a magnification of 50x.</figcaption></figure>

## Biomimetic Soft Robotic Tongue (BSRT): design & validation

<figure><img src="image_11.png" /></figure>

<figure><img src="image_12.png" /><figcaption>**Figure 3.** Soft robotic tongue actuator designed to replicate the oral preparation stage of semi-solid foods. (A) CAD representation of the soft actuator, including posterior and longitudinal cross-section views, and dimensions. (B) inflation/deflation sequence of the soft actuator, simulating: (1) food compression against the hard palate, (2) food anterior-posterior transport, and (3) and (4) the lateral displacement of the food bolus to facilitate thorough mixing with saliva. Graph (C) shows the pressure profiles recorded during the oral processing of apple puree (5 mL).</figcaption></figure>

<figure><img src="image_13.png" /><figcaption>**Figure 4.** The soft robotic tongue is located within an artificial oral cavity for simulating food oral processing (FOP), exemplified by the manipulation of a model food (apple puree, 5 mL). The delineation of the upper surface of the tongue is visually represented by a dashed red line, while the major portion of the food bolus exists between the upper surface of the tongue and a discernible pointed black line. The simulated stages encompass essential FOP actions: (1) compressing the food against the hard palate, (2) food anterior-posterior transport, and (3) and (4) lateral displacement of the food bolus to enable comprehensive mixing. Image (i) depicts the beginning of the actuation sequence, where the food is manually inserted into the oral cavity. At this stage, the lateral air chambers are not inflated and generate suction. Image (3') shows the moment when both lateral chambers come together during FOP.</figcaption></figure>

## Conclusions

Here, we present a unique three-dimensional pneumatic and multi-degree-of-freedom soft robotic actuator emulating the roughness, the applied pressure and movements, and the wettability of human tongue (68.1 ± 3.8°). By adjusting the actuation pattern, the artificial tongue can simulate clinically relevant bolus dynamics, operating under realistic conditions (i.e., salivary lubrication, temperature, and representative stresses/forces).

<figure><img src="image_14.png" /></figure>

<footnote>[1] Sethupathy et al. 2020. Food Reviews International 37, 538-571</footnote>

<footnote>[2] Panda et al. 2020. Innovative Food Science & Emerging Technologies 66, 102524</footnote>

<footnote>[3] He et al. 2022. Annual Review of Food Science and Technology 13, 167-192</footnote>

<footnote>[4] Marconati et al. 2020. Food & Function 11, 4363-4375</footnote>

<footnote>[5] Andablo-Reyes et al. 2020. Applied Material & Interfaces 12, 49371-49385</footnote>

<footnote>[6] Marconati 2019. PhD thesis, University of Surrey, U.K.</footnote>
# Toward a more realistic 3D biomimetic soft robotic tongue to investigate oral processing of semi-solid foods

Avila-Sierra, A.; Bugarin-Castillo, Y.; Voisin, J.; Mathieu, V.; Ramaioli, M.

UMR SayFood, U.Paris - Saclay, INRAE, AgroParisTech, Palaiseau, France

## Introduction

Current *in vitro* experiments reproducing food oral processing lack complete accuracy in capturing the complexity of the oral anatomy and physiological biomechanics of the human tongue.

While the importance of rheology and tribology of soft food is widely recognized [1-4], there is no system yet capable of realistically simulating the dynamic changes that occur in the human oral cavity when semi-solid foods are ingested.

The tongue, a soft tissue comprising micro-asperities known as papillae, contributes to modulate oral friction and lubrication, aided by tongue wettability.

These factors play a crucial role in controlling biophysical functions like sensory perception and food transport [5], affecting the amount of residue left in mouth after swallowing.

## Aim

It is crucial to develop a system that accurately mimics the intricate architectural, chemical, and mechanical features, as well as the complex motions of the human tongue. Such a system is essential for **gaining a comprehensive and quantitative understanding of how fluids and foods interact with the surfaces of the oral cavity.**

## Materials & Methods

<figure><img src="image_2.png" /></figure>

<figure><img src="image_3.png" /><figcaption>**Figure 1.** BSRT manufacturing (A) and schematics of the pneumatic system (B) used to fabricate/control the soft robotic actuator. Manufacturing: (1) pouring of the Ecoflex® mixture (containing Span 80 (0.5 wt %) to modulate wettability[6]) into the moulds, (2) adding the surface texturing mould, (3) de-moulding of the cured actuator and its base, and (4) final gluing of both parts.</figcaption></figure>

<figure><img src="image_4.png" /></figure>

<figure><img src="image_5.png" /><figcaption>**Figure 2.** 3D Image (A) showcases the CAD model of the artificial papillae based on average in vivo data [5]. This model includes a surface area of 10 x 10 mm, incorporating a randomized distribution. Moreover, (B) features a snapshot of the model surface pattern applied to the upper surface of the soft actuator. This image was captured using a digital camera, showcasing the soft robotic tongue surface at a magnification of 50x.</figcaption></figure>

## Biomimetic Soft Robotic Tongue (BSRT): design & validation

<figure><img src="image_6.png" /></figure>

<figure><img src="image_7.png" /><figcaption>**Figure 3.** Soft robotic tongue actuator designed to replicate the oral preparation stage of semi-solid foods. (A) CAD representation of the soft actuator, including posterior and longitudinal cross-section views, and dimensions. (B) inflation/deflation sequence of the soft actuator, simulating: (1) food compression against the hard palate, (2) food anterior-posterior transport, and (3) and (4) the lateral displacement of the food bolus to facilitate thorough mixing with saliva. Graph (C) shows the pressure profiles recorded during the oral processing of apple puree (5 mL).</figcaption></figure>

<figure><img src="image_8.png" /><figcaption>**Figure 4.** The soft robotic tongue is located within an artificial oral cavity for simulating food oral processing (FOP), exemplified by the manipulation of a model food (apple puree, 5 mL). The delineation of the upper surface of the tongue is visually represented by a dashed red line, while the major portion of the food bolus exists between the upper surface of the tongue and a discernible pointed black line. The simulated stages encompass essential FOP actions: (1) compressing the food against the hard palate, (2) food anterior-posterior transport, and (3) and (4) lateral displacement of the food bolus to enable comprehensive mixing. Image (i) depicts the beginning of the actuation sequence, where the food is manually inserted into the oral cavity. At this stage, the lateral air chambers are not inflated and generate suction. Image (3') shows the moment when both lateral chambers come together during FOP.</figcaption></figure>

## Conclusions

Here, we present a unique three-dimensional pneumatic and multi-degree-of-freedom soft robotic actuator emulating the roughness, the applied pressure and movements, and the wettability of human tongue (68.1 ± 3.8°). By adjusting the actuation pattern, the artificial tongue can simulate clinically relevant bolus dynamics, operating under realistic conditions (i.e., salivary lubrication, temperature, and representative stresses/forces).

<figure><img src="image_9.png" /></figure>

<footnote>[1] Sethupathy et al. 2020. Food Reviews International 37, 538-571</footnote>

<footnote>[2] Panda et al. 2020. Innovative Food Science & Emerging Technologies 66, 102524</footnote>

<footnote>[3] He et al. 2022. Annual Review of Food Science and Technology 13, 167-192</footnote>

<footnote>[4] Marconati et al. 2020. Food & Function 11, 4363-4375</footnote>

<footnote>[5] Andablo-Reyes et al. 2020. Applied Material & Interfaces 12, 49371-49385</footnote>

<footnote>[6] Marconati 2019. PhD thesis, University of Surrey, U.K.</footnote>