From The Swiss Federal Institute of Technology in Lausanne [EPFL-École Polytechnique Fédérale de Lausanne] (CH): “Steerable soft robots could enhance medical applications”

From The Swiss Federal Institute of Technology in Lausanne [EPFL-École Polytechnique Fédérale de Lausanne] (CH)

Jan Overney

Borrowing from methods used to produce optical fibers, researchers from EPFL and Imperial College have created fiber-based soft robots with advanced motion control that integrate other functionalities, such as electric and optical sensing and targeted delivery of fluids.

Over the past decades, catheter-based surgery has transformed medicine, giving doctors a minimally invasive way to do anything from placing stents and targeting tumors to extracting tissue samples and delivering contrast agents for medical imaging. While today’s catheters are highly engineered robotic devices, in most cases, the task of pushing them through the body to the site of intervention continues to be a manual and time-consuming procedure.

Combining advances in the development of functional fibers with developments in smart robotics, researchers from the Laboratory of Photonic Materials and Fiber Devices in EPFL’s School of Engineering have created multifunctional catheter-shaped soft robots that, when used as catheters, could be remotely guided to their destination or possibly even find their own way through semi-autonomous control. “This is the first time that we can generate soft catheter-like structures at such scalability that can integrate complex functionalities and be steered, potentially, inside the body,” says Fabien Sorin, the study’s principal investigator. Their work was published in the journal Advanced Science [below].

The researchers created the fibers with the thermal drawing process commonly used to produce fiber optic cables, similar to pulling a long string of cheese from a fondue and letting it harden. Material choice was critical, with elastomers – elastic polymers that return to their original shape when stretched – the preferred candidate: In addition to being flexible, they are soft enough to minimize lesions of delicate body tissues. But, says Andreas Leber, the first author of the study, “Historically, thermal drawing has been restricted to hard materials. Fortunately, our group had identified a class of thermoplastic elastomers that can be drawn and maintain their elastomeric properties after drawing.”

© Alain Herzog.

Integrating motion control, sensing, and drug delivery

To generate long fibers featuring multiple channels along their entire length, the researchers had to fine-tune the drawing process parameters. “An important characteristic of the process is the interplay between the viscosity of the material, which lets you draw a continuous fiber, and the surface tension, which can cause the channels within them to collapse,” says Fabien Sorin.

By getting the material properties, the drawing speed, and the temperature just right, the team could reliably produce the continuous channels, carefully arranged within the fibers at a micrometer scale, needed to give the fiber its robotic capabilities. For example, by using a motor to pull on one or several tendons introduced into channels – a well-established approach in smart catheters – doctors could control the orientation of the end of the fiber to guide it through the body.

Besides channels, the fibers can be equipped with a variety of elements using the thermal drawing process. “In addition to the tendons, the fibers can integrate optical guides, electrodes, and microchannels that enable drug delivery, imaging, electrical recording and stimulation, and other tools commonly used in robotics and medical applications,” explains Leber.

These functional elements also open the door to autonomous fiber-shaped robots. “The integrated optical guides give fibers the sense of sight. They can detect and avoid obstacles in their trajectory and even find targeted objects, such as cavities, all on their own,” continues Leber. Critical to this effort is a sophisticated control algorithm and software user interface developed from the ground up by the team in the lab.

Highly scalable fabrication

While it may sound complex, these multi-material fibers are remarkably simple to produce. “We use optical fiber fabrication technology, which is very scalable. You can generate hundreds of kilometers of optical fiber overnight. As a result, our fabrication approach brings a novel, scalable way to make soft catheter-like structures with an unprecedented combination of advanced functionalities.” says Sorin.

Remotely controlled catheters are only one of many exciting potential applications that this new class of fiber-based soft robots could enable. “The tendon-based approach to motion control is a first step of the development of thermally drawn smart catheters. The next step will involve moving toward electrical or magnetic actuation modes and testing the exciting opportunities of such fibers one step closer to clinical applications,” says Burak Temelkuran, co-author and group leader at the Hamlyn Center for Robotic Surgery at Imperial College.

Smart mattresses, soft prosthetics, and industrial robots

Soft robotic fibers also have a wealth of applications outside the human body. Mattresses could be equipped with them to monitor sleep quality or change their material properties in response to sensed pressure and physiological parameters, giving users a better night’s sleep. The fibers could be used to create soft prosthetics capable of responding to excess mechanical stress on a joint by becoming stiffer. And industrial or environmental sensing applications could include self-guiding soft robots that navigate based on information sensed by integrated heat sensors, haptic sensors, and even electrical and optical systems for vision.

Science paper:
Advanced Science
See the science paper for instructive material with images.

See the full article here .

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The Swiss Federal Institute of Technology in Lausanne [EPFL-École Polytechnique Fédérale de Lausanne] (CH) is a research institute and university in Lausanne, Switzerland, that specializes in natural sciences and engineering. It is one of the two Swiss Federal Institutes of Technology, and it has three main missions: education, research and technology transfer.

The QS World University Rankings ranks EPFL(CH) 14th in the world across all fields in their 2020/2021 ranking, whereas Times Higher Education World University Rankings ranks EPFL(CH) as the world’s 19th best school for Engineering and Technology in 2020.

EPFL(CH) is located in the French-speaking part of Switzerland; the sister institution in the German-speaking part of Switzerland is The Swiss Federal Institute of Technology ETH Zürich [Eidgenössische Technische Hochschule Zürich] (CH). Associated with several specialized research institutes, the two universities form The Domain of the Swiss Federal Institutes of Technology (ETH Domain) [ETH-Bereich; Domaine des Écoles Polytechniques Fédérales] (CH) which is directly dependent on the Federal Department of Economic Affairs, Education and Research. In connection with research and teaching activities, EPFL(CH) operates a nuclear reactor CROCUS; a Tokamak Fusion reactor; a Blue Gene/Q Supercomputer; and P3 bio-hazard facilities.

ETH Zürich, EPFL (Swiss Federal Institute of Technology in Lausanne) [École Polytechnique Fédérale de Lausanne](CH), and four associated research institutes form The Domain of the Swiss Federal Institutes of Technology (ETH Domain) [ETH-Bereich; Domaine des Écoles polytechniques fédérales] (CH) with the aim of collaborating on scientific projects.

The roots of modern-day EPFL(CH) can be traced back to the foundation of a private school under the name École Spéciale de Lausanne in 1853 at the initiative of Lois Rivier, a graduate of the École Centrale Paris (FR) and John Gay the then professor and rector of the Académie de Lausanne. At its inception it had only 11 students and the offices were located at Rue du Valentin in Lausanne. In 1869, it became the technical department of the public Académie de Lausanne. When the Académie was reorganized and acquired the status of a university in 1890, the technical faculty changed its name to École d’Ingénieurs de l’Université de Lausanne. In 1946, it was renamed the École polytechnique de l’Université de Lausanne (EPUL). In 1969, the EPUL was separated from the rest of the University of Lausanne and became a federal institute under its current name. EPFL(CH), like ETH Zürich (CH), is thus directly controlled by the Swiss federal government. In contrast, all other universities in Switzerland are controlled by their respective cantonal governments. Following the nomination of Patrick Aebischer as president in 2000, EPFL(CH) has started to develop into the field of life sciences. It absorbed the Swiss Institute for Experimental Cancer Research (ISREC) in 2008.

In 1946, there were 360 students. In 1969, EPFL(CH) had 1,400 students and 55 professors. In the past two decades the university has grown rapidly and as of 2012 roughly 14,000 people study or work on campus, about 9,300 of these being Bachelor, Master or PhD students. The environment at modern day EPFL(CH) is highly international with the school attracting students and researchers from all over the world. More than 125 countries are represented on the campus and the university has two official languages, French and English.


EPFL is organized into eight schools, themselves formed of institutes that group research units (laboratories or chairs) around common themes:

School of Basic Sciences
Institute of Mathematics
Institute of Chemical Sciences and Engineering
Institute of Physics
European Centre of Atomic and Molecular Computations
Bernoulli Center
Biomedical Imaging Research Center
Interdisciplinary Center for Electron Microscopy
MPG-EPFL Centre for Molecular Nanosciences and Technology
Swiss Plasma Center
Laboratory of Astrophysics

School of Engineering

Institute of Electrical Engineering
Institute of Mechanical Engineering
Institute of Materials
Institute of Microengineering
Institute of Bioengineering

School of Architecture, Civil and Environmental Engineering

Institute of Architecture
Civil Engineering Institute
Institute of Urban and Regional Sciences
Environmental Engineering Institute

School of Computer and Communication Sciences

Algorithms & Theoretical Computer Science
Artificial Intelligence & Machine Learning
Computational Biology
Computer Architecture & Integrated Systems
Data Management & Information Retrieval
Graphics & Vision
Human-Computer Interaction
Information & Communication Theory
Programming Languages & Formal Methods
Security & Cryptography
Signal & Image Processing

School of Life Sciences

Bachelor-Master Teaching Section in Life Sciences and Technologies
Brain Mind Institute
Institute of Bioengineering
Swiss Institute for Experimental Cancer Research
Global Health Institute
Ten Technology Platforms & Core Facilities (PTECH)
Center for Phenogenomics
NCCR Synaptic Bases of Mental Diseases

College of Management of Technology

Swiss Finance Institute at EPFL
Section of Management of Technology and Entrepreneurship
Institute of Technology and Public Policy
Institute of Management of Technology and Entrepreneurship
Section of Financial Engineering

College of Humanities

Human and social sciences teaching program

EPFL Middle East

Section of Energy Management and Sustainability

In addition to the eight schools there are seven closely related institutions

Swiss Cancer Centre
Center for Biomedical Imaging (CIBM)
Centre for Advanced Modelling Science (CADMOS)
École Cantonale d’art de Lausanne (ECAL)
Campus Biotech
Wyss Center for Bio- and Neuro-engineering
Swiss National Supercomputing Centre