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Device Technologies and Biomedical Robotics

Device Technologies and Biomedical Robotics - Poster Session A

Poster I19 - Bio-inspired Soft-bodied Robotic Pump for Transportation of Viscous Fluid and Solid Cargo

Thursday, October 24, 2024
10:00 AM - 11:00 AM EST
Location: Exhibit Hall E, F & G

Introduction:  The human body requires the transport of viscous fluids and solids through many biological processes, peristalsis being one such. This function, though, can be compromised due to several factors, specifically tumor growth, and results in lumen immobility. This dysmotility can prevail in the lungs where it causes respiratory difficulties while these constrictions in the oviduct create obstructions leading to reproductive issues. Therefore, restoring this essential function is a priority for current medical devices that aim to enhance the quality of life. Here we propose to design and implement a functional pump that actively restores the peristaltic motion by developing miniature soft robotic pumps that create an undulating motion. The pump, for this particular research, is tested inside a silicone-based esophageal model and can transport both viscous liquids and soft-bodied cargoes. The restored peristaltic motion was able to pump fluids with various viscosities and at different angles. The research also verifies the ability to transport different-sized soft-bodied cargoes. The mechanism can be adapted for other aforementioned medical purposes such as the female oviduct as well as the trachea. The pump functions wirelessly using a rotating magnet therefore omitting any surgical procedures that need to be conducted to perform similar functions.

Materials and

Methods:  Fabrication and Magnetization of Magnetic Modules
To do this, NdFeB particles and Ecoflex 00-30 were mixed to create a composite of the ratio 1:2 by weight. This mixture was spread onto an acrylic substrate with PET tape as walls and cured at 70 °C. Using a precise laser cutter, a 12 x 6 matrix was cut. Then these were magnetized by wrapping a 12-module strip around a cylindrical fixture on a glass slide and inserted into an impulse magnetizer with a magnetic field impulse of 2.3 T and a maximum discharging voltage of 300 V. For the back layer, pure Ecoflex-0030 was deposited onto an acrylic substrate with PET tapes as walls and cured at 70 °C for an hour.

Assembly and Model Integration
With a module-to-module distance of 1 mm, modules were attached in the correct order using fresh Ecoflex-0030 as an adhesive. The back layer was cut with a 0.5-mm fin length and a 4-mm anchor. Multiple sheets were organized onto a blanketing back layer, then rolled up and deployed inside a silicone esophageal model (use fresh Ecoflex-0030 as adhesive).

Additional Methods
The experimental setup was a magnetic actuation setup composed of a step motor to generate a rotating magnetic field. The viscous liquids used included syrup, glycerol, and porcine mucus (7:1 water to mucin ratio).

Results, Conclusions, and Discussions: Efficiency of Liquid Uptake and Recycling
With a phase shift of 3π/4 between the undulating sheets, the model was able to mobilize glycerol and eject it from the other end (as depicted in Figure 5). This motion then continued to provide constant liquid movement and allowed for the undulating sheets to recycle the glycerol and diffuse it even further.

Varying Viscosity Testing
After testing different viscous liquids, the pump can transport less viscous liquids like water as well as extremely viscous, and non-newtonian, fluids like mucus (with a 7:1 water to mucin ratio).

Varying Bead Diameter Testing
The pump could transport various cargo sizes where hydrogel beads of diameters 3.5, 4.5, and 5.75 mm were used. The undulating sheets had a phase shift of 3π/4.

Angle Inclination versus Fluids & Cargoes
Using 3-D printed spacers, the experimental setup was set at angles of 0, 5, and 10 degrees against gravity. The distance between the rotating magnet and the model was kept constant. It could transport liquids and 4.5-mm beads out to the other end up until the angle of 10 degrees.

Conclusion
To conclude, the research presents a wireless soft robotic pump that can transport liquids and solids efficiently. The fundamental undulating motion is realized by programming a magnetic sheet with a specific magnetization profile which is applied with iteration to its neighboring modules to encode an undulating motion through the sheet. The proposed wirelessly actuated robotic pump holds promise in enabling diverse implantable medical devices designed to address the challenges of lumen dysmotility in various diseases such as esophageal cancer.

Discussion
To improve the current design, the magnetic sheets could be scaled down using advanced manufacturing, i.e. micro-molding to adapt to narrower lumens. To increase the omniphobicity of the modules, they can be patterned with microstructures or coated with materials which would increase the transportation of fluids and liquids. This mechanism could be used for various lumens inside the human body to restore transportation abilities. For instance, it could be used to restore movement in the fallopian tube that helps carry eggs from the ovaries to the uterus.

Acknowledgements (Optional):