Miniature Biopsy Needle for Ductoscopy

In ductoscopy, the milk ducts of the breast are investigated using a so-called ductoscope. The ductoscope consists of a handle with three canals: (1) for insertion of the micro-endoscope, (2) for insertion of a tool, and (3) the irrigation canal to expand the milk duct, and a hollow tube that is inserted in the milk duct.

In case a lesion is found during this procedure, a biopsy procedure is performed using a biopsy basket. Unfortunately, this procedure is very unreliable and difficult to perform, often resulting in the need for a follow-up procedure.

In an effort to overcome this challenge, we have developed a biopsy needle that can be used during the ductoscopy procedure. The biopsy needle consists of two concentric cutting blades with a rectangular cut-out at the distal tip. By counter-rotating the cutting blades, a biopsy can be obtained, similar to the way a scissor works. The cutting blades are actuated using a handle in which the counter-rotating motion of the blades is transferred to an axial translation (see below).

In a proof-of-principle experiment, a milk duct phantom was manufactured out of gelatin. The biopsy needle was able to reliably obtain biopsy samples from this phantom. Furthermore, the biopsy needle was also successfully combined with the ductoscope.


  • Sakes A., Snaar K., Smit G., Witkamp A.J., and Breedveld P. (2018). Design of a Novel Miniature Breast Biopsy Needle for Ductoscopy. Biomedical Physics & Engineering Express. Accepted.

Devices for autonomous intraluminal surgery

This research is part of the AuTonomous intraLuminAl Surgery Innovative Training Network ( ATLAS-ITN) and has received funding from the European Union’s Horizon 2020 research and innovation programme under the Marie Sklodowska-Curie grant agreement No 813782 .

The goal of this project is to develop smart, flexible robots that autonomously propel themselves through complex, deformable, tubular structures. This calls for seamless integration of sensors, actuators, modelling and control.

Two early-stage researchers, Fabian Trauzettel (ESR 1) and Chun-Feng Lai (ESR 12), will be based at TU Delft, while two others, Di Wu (ESR 11) and Zhen Li (ESR 13) will have TU Delft as their secondary institution. They will focus on multi-steerable catheter technology, follow-the-leader control, control of multi-DOF catheters in unknown environments, and path planning / real-time re-planning. Details of their projects can be found here.

Research in the network will be conducted at KU Leuven, TU Delft, University of Strasbourg, Politecnico di Milano, Università di Verona, Scuola Superiore Sant’Anna Pisa, and UPC Barcelona.

SIGMA Catheter – steering inside the Heart

Developed in 2016-2017, diameter Ø3 mm, lumen Ø1 mm

In recent years, steerable catheters have been developed to combat the effects of the dynamic cardiac environment. However, current solutions are bound to a number of limitations: (1) low torsion, (2) shaft shortening, (3) high unpredictable friction, and (4) coupled tip-shaft movements. These effects make it very hard to steer in tortuous blood vessel and inside the heart.

In order to tackle these limitations we developed a novel multi-steerable catheter prototype with four degrees of freedom. The tip has two steering segments that can be steered in all directions, controlled by two joysticks on the handle: one for the thumb and one for the index finger. The prototype features automatic lock of the steering angle once the joystick is released.

To solve the four limitations mentioned above we used eight miniature Bowden-cables inside of the flexible shaft for independent omnidirectional steering of each tip segment. As each segment can steer in all directions, twisting the shaft is not needy for directing the catheter tip, which solves the issue with low torsion (1). The issue with shaft shortening (2) is solved with the Bowden-cables which are axially incompressible. The Bowden cables generate very low predictable friction (3) and coupled tip-shaft movements (4) are absent as the Bowden-cables transfer the joystick motions directly to the tip without influencing the shaft.

The ability to steer inside the heart with a variety of complex shapes and curves opens great possibilities for complex catheter interventions. We evaluated our SIGMA catheter in a transparent 3D printed heart, based on MRI-images and created by the company Materialize, as well as ex-vivo in a beating porcine heart at the LifeTec Group. Both evaluations show very promising results and superior behaviour as compared to conventional steerable catheters.


Ali A., Sakes A., Arkenbout E.A., Henselmans P., Starkenburg R. van, Szili-Torok T., Breedveld P. (2019). Catheter steering in interventional cardiology: mechanical analysis and novel solution. Proc. Inst. Mech. Eng. Part H: Journal of Engineering in Medicine, 12 p.


MemoFlex 1 – Mechanical Surgical Snake

Developed in 2016-2017, diameter Ø5 mm

During complex surgical procedures such as in skull-base surgery, there is a need to reach difficult-to-reach locations via narrow anatomic corridors. Performing surgery along complex 3D pathways requires a snake-like instrument that memorizes the 3D shape of the followed pathway and shifts the shape backward as the instrument moves forward. This snake-like method of locomotion is called “follow-the-leader locomotion”, in which the head is the “leader” and the body follows the pathway of the head, see the following animations:

Follow-the-leader locomotion requires a segmented multi-steerable instrument as well as a memory in which the angles of the segments can be stored and shifted. In robotic approaches, the actuation usually occurs by a range of electric motors controlled by a computer. Although feasible, this will result in a very complex system requiring additional safety measures to ensure reliability during surgery.

In a desire to create a simpler system, we explored an alternative follow-the-leader approach by using a mechanical memory. Following the design approach of our MultiFlex, the MemoFlex 1 contains a 12 cm long, Ø5 mm multi-steerable tip with 14 segments that can be controlled individually in 28 Degrees of Freedom. Using 56 steering cables, the tip is connected to a bendable handle. When the handle is bent in a certain shape, the shape is mirrored and replicated by the tip.

The shape memory is a pre-bent stainless steel rod that slides through the bendable handle, driven by a crank. As the rod slides through the handle, its shape is detected by a 3D-printed compliant helicoid insert that makes the handle follow the shape of the rod precisely. The mechanism replicates the handle-shape to the tip which will then maneuver along a curved pathway equivalent to the shape of the pre-bent rod. The shape of the pre-bent rod can be derived from CT or MRI-images.

Our novel copy-and-replication mechanism shows promising results. Yet, the prototype has a high mechanical complexity. We therefore continued this research with an improved prototype, the MemoFlex 2, which contains aan improved shape memory mechanism and a strongly simplified compliant 3D-printed tip.


Octopus-based Instrument used for first time in OR

The ‘mechanical octopus’, a steerable laparoscopic instrument used for minimally invasive surgery in the abdominal cavity, has been used for the first time in an operating room.

Surgeons at the Haags Medisch Centrum are positive about the benefits that the innovative technology in the LaproFlex gave them during a gynaecological operation. The technology behind the instrument was conceived by Paul Breedveld, professor of Medical Instruments & Bio-Inspired Technology. Jules Scheltes, who also obtained his PhD at TU Delft in the field of medical product development and who co-founded the Dutch company DEAM, has been working these past two years to market the product. Following an exciting period, he received CE certification earlier this summer for the LaproFlex and is producing and selling it in Europe.

Paul Breedveld
‘The LaproFlex is an example of research at a university finding its way into industry.’

Jules Scheltes
‘Co-founder Wimold Peters and I are especially proud that we have managed to pull this off with our team. Surgeons have indicated that the instrument is providing them with a better view of the organ they are operating on, and that they can access it from an optimal approach route and are not inconvenienced by intersecting instruments in their field of operation anymore. This is great news. This is exactly what we’ve been working towards.’

What makes this instrument special is that it has a flexible tip. This is made possible by an ingenious steering system based on the anatomy of an octopus’ tentacle, the so-called cable crane mechanism, which ensures that the scissors or grasper can be steered in every direction. Paul Breedveld and the researchers in his Bio-Inspired Technology Group (BITE) have further developed this technology, which has now been globally patented, into a large number of prototypes of steerable surgical instruments. DEAM is a spin-off company of the BITE group that develops steerable precision instruments for minimally invasive interventions. DEAM collaborates with a number of universities of technology and university medical centres. The LaproFlex is the first commercially available instrument using a cable crane mechanism and is considered to be a particularly affordable, disposable alternative for the extremely pricey Da Vinci operation robot.


Pulze Hammer II: Catheter

Developed in 2017-2018, diameter 2 mm

We want to go deeper into the human body, using incisions that are smaller or even non existent. For this purpose we need small flexible tools that are able to deliver sufficient forces without buckling.

In an effort to facilitate high force delivery in a small flexible medical instrument, the pulze catheter prototype (2 mm) has been developed. Buckling is prevented by using a dynamic loading method, in which a high-speed indenter collides with the non-moving target. The flexible prototype consists of a distal spring-loaded indenter, which is manually actuated using a compliant (re)load mechanism, allowing for loading, locking, and (re)loading of the prototype while inserted in the body.

We are currently testing this catheter ex-vivo. Further development of this crossing prototype may in time allow for performing surgery deep inside the body.


Design of instruments for veterinary interventions

If you are looking for a challenging assignment that combines bio-inspiration with actual animals, I have currently multiple projects available directed towards veterinary research. The projects are in collaboration with the Rotterdam Zoo and Faculty of Veterinary Medicine of the University Utrecht. Projects are aimed at surgical interventions of different types of animals, including elephants, rhinos, birds, and horses. A selection of the projects is illustrated below:

  • Suturing abdomen of larger animals

Suturing of the abdomen of larger animals is difficult and often results in ripping along the suture line due to the large force on the stitches. This ripping will in most cases lead to death of the animal. Since operations, such as caesarean sections, can be necessary at time to safe both the mother as well as the offspring, a solution should be found for this problem.

  • Design of an stand-up aid for horses after surgery

When horses suffer a bone fracture, the bone needs to be surgically stabilised using screws and plates. In many cases this is done successfully. However, after the horse wakes up after surgery, they are often very tense and tend to panic, which can result in refracture of the bone. The goal of this project is to design a device that can help the horse to stand up safely after the surgery.

  • Design of a bullet removal device in Elephants and Rhinos

In Africa, elephants and rhinos are often hunted for their tusks. Luckily, on some occasions, the elephants and rhinos are able to get away. However, they often sustain severe damage due to bullet wounds. The main challenge the veterinarians face is the removal of these bullets. These bullets are often very deep inside the animal and, therefore, difficult to reach. Furthermore, they often migrate through the body to deeper locations, potentially becoming life threatening. In this assignment, you will develop a bullet removal device for elephants and rhinos that can be used in the field.

  • Design of a tusk extraction device for Elephants

When an elephant’s tusk breaks off, the living tissue inside the tusk will become exposed. If it is not possible to safe the tusk, the best option is to extract it to prevent further harm to the elephant. However, current methods for removing tusks are difficult to perform. Therefore, in this assignment you will develop a new type of instrument that allows for easy and fast task extraction.

  • Design of a smart hatch for animals in Rotterdam Zoo (internship)

In Rotterdam Zoo, they would like to build a smart hatch system for their Wallabies. This system will allow them to keep track of which animal is where and also allows them to capture specific animals with minimal stress.

  • Design of a tusk protection device for Elephants in Rotterdam Zoo (internship)

On some occasions, an elephant tusk might get damaged and a crack may form. On these occasions, veterinarians often place a metal ring around the tusk to protect the living tissue inside the tusk and prevent further damage. However, these rings are heavy and do not offer full protection. Therefore, in this assignment you will design a new type of tusk “ring”.

Contact: Aimée Sakes,

EU – 3D Printed medical devices

This research is part of EU Interreg 2 Seas Mers Zeeën 3D MED: Development and streamlined integration of 3D printing technologies to enable advanced medical treatment and its widespread application.

The goal of this project is to research the possibilities of 3D printing for the advanced design and production of medical devices, in order to improve affordability and accessibility of medical treatment. The benefit of 3D printing is that complex shapes can be created in one single production step, which offers great potential for easy manufacturing and added functionality. The focus will be on developing design methods for complex medical devices with internal mechanisms used in eye surgery, which can be printed as one functioning assembly. This research is executed in collaboration with DORC, the Dutch Ophthalmic Research Centre.

4TU – Soft Robotics

This programme is a collaboration of the four technical universities of the Netherlands (4TU): Eindhoven University of Technology, University of Twente, Wageningen University, and Delft University of Technology.

Conventional robots operate in pre-programmed environments, enabling the execution of repetitive tasks at superhuman speed and accuracy, based on a design of interlinked rigid segments that are position controlled. A radically different approach is required to enable robots to safely interact with organic matter (which is inherently vulnerable and unpredictable) or to operate in human-inhabited environments. Robots should be soft and compliant, but designing, manufacturing, modelling and controlling them brings many scientific and technological challenges. These challenges have recently begun to be addressed in the emerging research community of ‘soft robotics’.

Our soft robotics programme aims to establish a leading soft robotics community in the Netherlands, that will establish an integrated design approach for soft robotic hardware, control and actuation, inspired by nature. Unlike conventional robots, humans and animals are soft and flexible, and adaptive. While in conventional robots components such as motors, sensors, beams and computer are stacked, in animals functionalities such sensing, control, and actuation are fully integrated, distributed, and robust (i.e., failure of parts does not lead to a non-functional system). In biology the nervous system is distributed over the entire body, and the ‘design’ of the biomechanical motion systems reduces the control demands for the nervous system. For this reason, we want to unravel the solutions found in nature, and use them as inspiration for the design of Soft Robots.

Novel non-assembly 3D printed structures will be explored to integrate electronics and embedded micro-actuators. Additionally, we will investigate bio-inspired power cable structures that can withstand extreme stretch due to their shape. In close collaboration with Wageningen University, we will combine bio-to-techno transfer with techno-to-bio transfer, whereby knowledge of biological functionality is gained from building soft robotic devices.

For more information about this project, please contact Aimée Sakes,

Design of a Self-Propagating Tree-Root Inspired Needle (CLOSED)

Tree roots are able to find their way through the soil towards a water source. They do this by growing their roots in a special way. First, they extend the middle part of the root into the soil. Second, they thicken the roots.

In this assignment, you will develop a soft tree-root inspired needle that is able to propel itself through the body in a minimally invasive way. The challenge will mainly lie in how you can propagate yourself through the body.

If you are interested in this assignment, please contact: Aimée Sakes,

Solving medical problems through nature’s ingenuity