# Electroadhesive Stabilization of Soft Robotic Catheters

Mostafa A Atalla, Tim de Visser, Aimée Sakes, Michaël Wiertlewski, Yasemin Vardar

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Mostafa A Atalla, Tim de Visser, Aimée Sakes, Michaël Wiertlewski, Yasemin Vardar. Electroadhesive Stabilization of Soft Robotic Catheters. 2025. hal-05022573

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# Electroadhesive Stabilization of Soft Robotic Catheters

Mostafa A. Atalla<fnref n="1" />,<fnref n="2" />,*, Tim de Visser<fnref n="1" />,*, Aimée Sakes<fnref n="1" />, Michaël Wiertlewski<fnref n="2" /> and Yasemin Vardar<fnref n="2" />

## I. INTRODUCTION

Minimally invasive endovascular interventions have revolutionized cardiovascular treatments, offering significant advantages over traditional open-heart surgeries, including shorter recovery times and reduced infection risks. Central to these procedures is interventional catheterization, where catheters are inserted through small incisions and guided through the vasculature to the targeted region. Once in position, interventions such as stent placement or heart valve installation are performed. A critical factor in the success of these procedures is the stability of the catheter, which ensures precision and allows force exertion when necessary.

However, maintaining catheter stability remains a significant challenge. Catheters are typically coated with low-friction materials to reduce the risk of vascular damage when navigating through blood vessels. This necessary design choice has a drawback: The low-friction coating makes the catheter slippery, making it highly sensitive to small perturbations and thus compromising its stability. This problem becomes even more pronounced in open spaces, such as inside the beating heart, where the absence of contact with surrounding tissue increases the instability at the tip. This instability limits catheter functionality, particularly in tasks that require high precision and force, such as valve replacement or tissue biopsy.

State-of-the-art catheter stabilization techniques range from external methods, such as securing short peripheral intravenous catheters with dressings, tape, sutures, or adhesives [1–3], to internal anchoring solutions, such as inflatable balloons [4], origami actuators [5] and foldable braces [6, 7]. External methods lack dynamic friction control and are not suitable for long catheters; internal approaches, such as balloon tip catheters, focus solely on tip stabilization, risking tissue damage or perforation from high localized pressure [8–10]. Furthermore, incorporating mechanical components for stabilization increases the complexity of the device and the risk of failure.

In this work, we propose a novel active stabilization mechanism for catheters that addresses the shortcomings of existing methods; see its concept Fig.1. The stabilization mechanism uses electroadhesion to enable the catheter to adhere to its surrounding tissue throughout its length when needed, providing a stable base for operation in open spaces.

<figure><img src="image_2.png" /><figcaption>Fig. 1. (a) Electroadhesive catheter design and prototype. (b) Working principle of electroadhesive catheters.</figcaption></figure>

We introduce our proof-of-concept for this mechanism and present the preliminary experimental validation results.

## II. MATERIALS & METHODS

Electroadhesion is an electrostatic phenomenon in which adhesion forces between two surfaces are generated by inducing surface polarization charges through a voltage difference [11, 12]. Electroadhesion can generate strong adhesion pressures exceeding (10 kPa) at operating voltages of (3 – 5 kV) with a low current rating (1 mA). This phenomenon has been utilized in various applications, including soft grippers [13–15], robotic locomotion [16–18], and tactile interfaces [19, 20]. Depending on the substrate,

<footnote>* authors contributed equally</footnote>

<footnote n="1">¹Department of BioMechanical Engineering, Faculty of Mechanical Engineering, Delft University of Technology, Delft, The Netherlands</footnote>

<footnote n="2">²Department of Cognitive Robotics, Faculty of Mechanical Engineering, Delft University of Technology, Delft, The Netherlands</footnote>
<figure><img src="image_3.png" /><figcaption>Fig. 2. (a) Experimental setup for sliding friction experiments. (b) Recorded coefficients of friction between the catheter prototype and friction substrate over the sliding distance, measured at varying input voltages. (c) Box plots showing the average dynamic friction coefficients calculated at varying input voltages, with six trials conducted for each input voltage. Red horizontal lines indicate the medians, while red crosses (×) represent outliers.</figcaption></figure>

electroadhesion devices use monopolar, bipolar, or multi-
polar (interdigitated) electrode configurations. Monopolar
electrodes adhere to conductive substrates, while bipolar
and multipolar configurations work with both conductive
and non-conductive surfaces. The adhesion forces can be
controlled by varying the voltage and can dissipate when
power is turned off [21, 22]. The ability of electroadhesion
to provide strong and controllable adhesion, its adaptability
to diverse surfaces, and its compatibility with thin, flexible
designs make it a promising solution for addressing the
stabilization needs of interventional catheterization.

The proposed electroadhesive catheter features an inter-
digitated electrode design created through helical windings
embedded over the catheter shaft, as shown in Fig.1 (a&b).
The helical windings seamlessly integrate with the catheter’s
cylindrical shape by embedding each electrode wire into pre-
made helical slots on the backing layer. These slots enable
precise electrode placement and maintain proper insulation
between the electrodes, ensuring reliable device functionality.
The assembled backing layer and electrodes are coated with
a dielectric layer to safeguard surfaces in contact with the
electroadhesive catheter.

To validate the concept, we fabricated a scaled-up proto-
type of the electroadhesive catheter (8 mm outer diameter),
as shown in Fig.1 (a). A 6 mm PVC Nelaton catheter (Zarys,
Poland) was cut to length and placed in a 3D-printed mold.
This mold was used to create the backing layer around the
catheter body using Ecoflex 00-50 (Smooth-On, PA, USA),
which was cured for 24 hours. We then embedded two
(0.5 mm) square copper wires into the helical slots on the
backing layer. Then, we manually dip-coated the dielectric
layer with Ecoflex 00-50 at (0.5 mm/s) and cured it for four
hours. After curing, the wires were trimmed, and connectors
were added for high-voltage amplifier connection.

We conducted a proof-of-concept experiment, illustrated
in Fig.2 (a), to measure the sliding friction force of the elec-
troadhesive catheter moving on a curved conductive copper
substrate of diameter (22 mm) at different input voltages.
The catheter was mounted using a 3D-printed bracket and

loaded onto the substrate with a normal force of (0.5 N)
using a linear stage (NRT150/M, Thorlabs, NJ, USA). The
substrate was actuated horizontally at a constant speed of
(0.1 mm/s) using a second linear stage. A 6-axis force
sensor (Nano43, ATI, NC, USA) mounted at the base of the
catheter bracket recorded the normal load and sliding friction
forces throughout the experiment. For each input voltage, we
repeated the experiment six times.

III. RESULTS & DISCUSSION

The friction experiments validated the ability of the pro-
posed catheter to generate increased friction upon activation
of the electroadhesion electrodes. When the catheter slid
over the curved substrate, the coefficient of friction initially
rose to the static friction level and then stabilized at the
dynamic friction level, as shown in Fig.2 (b). Increasing the
applied voltage resulted in higher friction forces, potentially
enhancing adhesion and stability. As depicted in Fig. 2 (c), at
relatively low voltages (< 1 kV), we observed little friction
increase, likely due to the marginal adhesion forces generated
at these levels. Beyond 1 kV, friction increased linearly
with voltage, reaching up to a 12% increase at (2.5 kV).
These results confirm the ability of the proposed catheter to
increase friction on demand, which could potentially fulfill
the stability requirements of interventional catheters.

IV. CONCLUSION & FUTURE WORK

In this work, we introduced the concept of electroadhesive
catheters, which utilize electroadhesion to actively stabilize
interventional catheters by adhering to the vessel walls on de-
mand, enabling precise operation. We fabricated a scaled-up
prototype based on the electroadhesion interdigitated design
pattern. Preliminary validation experiments demonstrated the
prototype's ability to increase friction by up to 12% at 2.5 kV
input voltage, confirming the feasibility of the design and
its potential for catheter applications. In the future, we plan
to enhance the system to achieve a higher friction increase
percentage and to test the system in a clinically relevant
environment in tissue phantoms and ex-vivo animal tissues.
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