Hello everyone,
I want to share a project proposal I’ve developed for a 20 mm biohybrid soft robotic platform called the Tripodal Thinker (Project TT).
(Rough 2D Draft)
My research is heavily focused on chemically actuated robots, soft robotics, biomimetic/bioinspired robotics, and biohybrid robotics, but I am looking to connect with the Open Robotics community to get feedback on the mechanical modeling, kinematic conversion, and future control/sensing loops.
The Core Concept
The Tripodal Thinker is an autonomous bio-hybrid system designed to achieve directional locomotion through the integration of living neural and musculoskeletal tissue. Instead of traditional motors, it utilizes functional neuromuscular junctions (NMJs) to drive movement.
- The Chassis: A 20 mm flexible polydimethylsiloxane (PDMS) structural frame featuring three legs oriented in a tripodal stance.
- The Neural Engine: A central vertex cavity (5 mm diameter, 2 mm depth) houses a 0.04-inch cerebral organoid derived from human-induced pluripotent stem cells (iPSCs).
- The Actuators: Each leg features four micro-grooves (15 μm width and depth). Canals 1–3 are functionalized with Laminin-111 and Matrigel to grow aligned C2C12 skeletal muscle myotubes. Canal 4 is passivated with Pluronic F-127 to act as an open metabolic conduit for oxygen and nutrient flux.
The Kinematics & Locomotion Mechanics
The system relies on a mechanical passive compliance strategy:
- The “Wedge” Principle: Each foot features a 45° angled slant. This geometry functions like a mechanical one-way door—allowing the chassis to slide forward easily but “catching” the substrate to prevent slipping backward.
- Force Conversion: Rhythmic acetylcholine (ACh) releases from the central organoid trigger coordinated contractions in the leg myotubes. This inward muscular pull is converted by the 45° slanted feet into a directional forward push.
- Target Velocity: We are modeling a baseline locomotion speed between 5 mm to 20 mm per hour inside a controlled liquid media environment.
Project Milestones & Verification Goals
- Signal Fidelity: Achieving clean Signal-to-Noise Ratios (SNR) of neural bursts via calcium imaging or micro-electrode arrays that map directly to muscle twitches.
- Chemotactic Navigation: Evaluating autonomous decision-making by placing nutrient/growth factor gradients in the dish and measuring directional velocity changes toward the target.
- Actuation Efficiency: Sustaining locomotion using only the biochemical energy provided by the fluid medium, without relying on external optogenetic or electrical pacing.
Where I Need Engineering & Robotics Collaboration
Because this is an entirely compliant, non-linear biological system, standard rigid-body physics engines don’t easily apply. I would love to get feedback or collaborate with researchers skilled in:
- Soft Body Simulation: Has anyone successfully modeled tissue-actuated PDMS frameworks using soft-body platforms, Gazebo plugins, or the SOFA framework?
- Computer Vision Tracking: Strategies for setting up low-overhead micro-optical tracking pipelines to measure real-time multi-axial deformation of a 20 mm device inside an incubator.
- Compliance Modeling: Optimizing the 10:1 PDMS ratio or the 45° foot geometry to match the contraction forces generated by differentiated C2C12 myotubes.
You can check out my full working concept document here: Project TT: Development of a 20 mm Bio-hybrid Tripod - Google Docs
I would highly value any technical feedback on the kinematic assumptions, simulation pathways, or fabrication logic!
Best regards,
Aleph Jeremiah Rambie