Biointegrable soft actuators alimented by metabolic energy

Project Information

INTEGRATE

Grant agreement ID: 101046333

DOI

10.3030/101046333

Project closed

EC signature date 9 February 2022

Start date 1 June 2022

End date 31 May 2026

Funded under

• The European Innovation Council (EIC)

Total cost

€ 1 698 750,00

EU contribution

€ 1 698 750,00

Coordinated by

VELTHA IVZW
Belgium

Periodic Reporting for period 2 - INTEGRATE (Biointegrable soft actuators alimented by metabolic energy)

Reporting period: 2023-06-01 to 2024-11-30

Summary of the context and overall objectives of the project

State-of-the art implantable actuating devices, such as automated prosthetics, have time-limited operational capacities because they are sustained by batteries which, ultimately, rely on external power sources to be recharged. INTEGRATE proposes a radically new way to solve this problem: use metabolic energy from the patient to power implanted devices. To achieve this ambitious goal, INTEGRATE will develop i) new 3D printable soft actuating materials inspired by human muscles whit high performances and low power consumption and ii) an artificial organ capable of harvesting metabolic (biochemical) energy and transforming it into electricity. The actuating materials (Bionic Muscles) will be prepared via the self-assembly of biocompatible colloidal liquid crystals and stimuli-responsive polymers. A modular design and 3D printability will offer the possibility to manufacture these materials on the basis of the patient’s anatomy and needs. The Energy-Harvesting Organ will be capable of converting pH differences within various body fluids (e.g. gastric juice and saliva) into electricity with high efficiency, providing the necessary power to sustain the Bionic Muscles. This research has the potential to revolutionize the field of implantable devices and will lead to a turning point in robotics, wearable technologies, materials science, energy conversion, and materials engineering.

Work performed from the beginning of the project to the end of the period covered by the report and main results achieved so far

During the first year of activity, the INTEGRATE team reached the following milestones:
1) We developed a computational tool that makes it possible to predict how the building blocks of the artificial muscles behave when mixed in solution before and during 3D printing. This tool is extremely important for the optimization of a 3D printing process that favors long-range alignment of the building blocks
2) We developed a computational tool that makes it possible to predict the actuation properties of the 3D-printed artificial muscles as a function of the size and the shape of the colloidal particle (cylindrical or plate-like), the molar mass of the polymers and their chemical nature. The results from these computations show that the artificial muscles proposed by INTEGRATE will exhibit actuation properties comparable or superior to that of human muscles. Unlike muscles, that can only perform active contraction, these actuators will be capable of controlled expansion and contraction.
3) We selected cylindrical particles as first-generation building blocks for the artificial muscles and we selected a material that can be obtained from renewable resources. We were successful in grafting stimuli-responsive polymers onto the particles. These functionalized particles were then used to formulate a 3D-printable ink.
4) We are currently exploring four alternative strategies for the development of the artificial electric organ using hydrogels, commercial membranes, ultrathin self-assembly membranes with intrinsic selectivity and biomimetic membranes. We were able to build hydrogel-based soft batteries with power densities that exceed 1.5 W/m2 per repeating unit. These batteries are powerful enough to aliment small electronic circuits. Because of their composition and the tendency to quickly discharge, these batteries are not suitable for INTEGRATE’s purposes, yet are a useful test bench for the development of more advanced technologies.
We used commercial membranes to construct an artificial electric organ that converts ion gradients between body fluids into electricity. This strategy might pave the way to the fast realization of an electric organ prototype with medium-term market potential.
We are also trying to develop energy-converting membranes inspired by biological membranes. We were able to synthesize block copolymers capable of assembling into planar membranes. Using a templated self-assembly strategy, we prepared biomimetic membranes with thickness of 30 nm and surface areas as large as 8 cm2. We demonstrated that the incorporation of natural ion carriers makes these membranes selective for specific ions. This high-risk-high-gain strategy seems promising to yield high-performance artificial electric organs inspired by the anatomy of electric fish on the long term.

Progress beyond the state of the art and expected potential impact (including the socio-economic impact and the wider societal implications of the project so far)

The research activities introduced in the previous section yielded several important results beyond the state of the art. The computational method enabling the prediction of the actuation properties of the artificial muscles is new from a methodological point of view and has been recently published in the open-access Journal of Chemical Physics (https://doi.org/10.1063/5.0129105). For the first time to our knowledge, we were able to prepare cellulose colloidal particles grafted with photo-cross-linkable and stimuli-responsive polymers. This breakthrough has enormous innovation potential beyond the field of actuators as it introduces a new type of 3D-printable formulation. A patent application to protect these results is currently in preparation. Finally, the new method developed to form molecularly thin bioinspired membranes has important implications in the fields of membrane science and biophysics. The method is described in a paper currently under peer-review for publication.

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