Microbots: Medical Infantry | David Cappelleri | TEDxPurdueU
The speaker details microbots, submillimeter robots, engineered using electromagnets and magnetic feet, to revolutionize medicine by enabling precise force application, clot removal in deep brain areas, and targeted drug/radioactive seed delivery, asserting that *the only limit is your imagination*. ## Speakers & Context - Speaker showcasing fabricated microbots at Purdue University. ## Theses & Positions - Microbots are essential for medical applications because they offer unprecedented capabilities unattainable with larger macro-scale robots. - The primary advantage of microbots in medicine is precision: they allow quantifying subtle forces applied to cells, enabling better diagnostics (e.g., distinguishing cancer cell stiffness) and treatments. - Microbots can enable less invasive medical procedures, such as clot removal or biopsies, compared to current invasive methods. - The ultimate potential involves equipping microbots with onboard computers, cameras, intelligence, arms, and hands, allowing them to function like natural components within the body. ## Concepts & Definitions - **Microbot/Micro robot**: A robot operating at submillimeter dimensions. - **Cytoskeleton**: The internal skeleton structure found within a single cell. - **Mechanobiology**: The field studying the forces exerted on cells and how the cell reacts to those forces and develops. - **Stiffness (cell)**: The quantitative relationship between applied force and resulting cell displacement for a cell. ## Mechanisms & Processes - **Electromagnet Control**: Using surrounding electromagnets to generate controlled magnetic fields, allowing the robot to move precisely within a plane. - **Tumbling Locomotion**: A method for the robot to move over rough terrain by rolling and tumbling, which is necessary on sticky biological surfaces. - **Sliding Mode Operation**: A process involving controlled *stick-slip motion* that allows the robot to move along a surface by cyclically changing magnetic fields. - **Force Measurement**: Using a vision-based micro force sensor—a soft compliant structure—to observe the deformation of an object (like a microsphere) and calculating the applied force from that deformation. - **Autonomous Navigation**: The robot planning a path around obstacles by receiving pseudo-GPS coordinates and following them independently. - **Independent Control (Swarms)**: Achieving coordinated movement among multiple robots by using patterned, shrink-wrapped electromagnets (or micro strips of wire) arranged in an array to generate independent directional forces (up, down, left, right). ## Named Entities - **Joe**: A man who suffered a massive stroke requiring clot removal from a deep brain area. - **Purdue**: Location where the speaker showcased the fabricated robots. ## Tools, Tech & Products - **Electromagnets**: Used to surround the workspace and control the robot's movement by creating magnetic fields that can be turned on and off. - **Magnetic Feet**: Added to the robot, possessing magnetic properties different from the hat, allowing the robot to negotiate rough terrain. - **Magnetic Body**: The core component of the robot, which is susceptible to external magnetic fields. - **Soft Compliant Structure**: Used as the end effector, designed to deform when pushed on an object, facilitating force measurement. - **Micro force sensor**: Integrated system using vision observation of deformation to calculate applied force. - **Micro robot**: Small bot with onboard computers, cameras, intelligence, arms, and hands (future goal). - **Micro coils**: Prototyped components used for precise, independent magnetic control. - **Micro strips of wire**: Alternative, cheaper/easier technology used in two layers to generate patterned directional forces for independent robot movement. ## Numbers & Data - **100 microns**: Diameter of a human hair used for scale reference. - **8 human hair**: Approximate width of the initial microbots discussed. - **7 human hair**: Approximate height of the initial microbots discussed. - **Three human hairs wide by four human hairs long**: Dimensions of the developed tumbling robot. - **700 microns footprint**: Size of one of the sensing mobile micro robots. - **Four millimeters by four millimeters**: Size of the prototyped coils. - **Two millimeters in diameter**: Size of the independently moving robots prototyped. - **300 microns in diameter**: Desired size for micro coils for scalable manufacturing. ## Examples & Cases - **Lukes's biography**: (This example appears to be misplaced from another source and is ignored as it has no connection to the current transcript content). - **Microbot on biological tissue**: Demonstrates using tumbling locomotion on a sticky surface where simple pulling fails. - **Robot negotiating a penny**: Example of traversing features on the same size scale as the robot itself. - **Traversing different bumps**: Example of navigating varied topography within the workspace. - **Inclined planes**: Example of managing slopes during locomotion. - **Biologists in a petri dish**: Using robots to move individual cells out of a concentrated group for experimentation or arrangement. - **Force comparison**: Applying the same force to two different cells (Cell A and Cell B) to measure their distinct force-displacement relationships (stiffness). - **Sensing micro robot on a microsphere**: Demonstrates tracking deformation of a cell (microsphere) to determine the applied force. - **Team of three robots**: Example demonstrating the independent, patterned control of multiple robots using magnetic arrays. - **Advanced Manufacturing**: Using the system to assemble very small components, like micro-scale LEGOs. - **Joe's stroke**: Case study of a massive stroke requiring clot removal from a deep brain area where surgeons struggle. - **Targeted Drug Delivery**: Loading microbots with drugs to achieve higher concentrations at a tumor site compared to traditional diffusion. - **Radioactive Seed Delivery**: Using microbots to deliver radioactive seeds for cancer treatment instead of invasive procedures. - **Biopsies**: Using spikes/spokes on the robot to collect tissue samples internally for analysis, minimizing invasiveness. ## Trade-offs & Alternatives - **Battery Power vs. Wireless Control**: Large robots can use batteries; microbots require magnetic actuation (electromagnets). - **Large Tires vs. Magnetic Feet**: Magnetic feet are better for negotiating sticky, internal surfaces. - **Probes vs. Micro Robots**: Probes lack precision in force measurement, risking cell damage; microbots offer quantifiable force application. - **Single Control vs. Swarm Control**: Individual control vs. coordinated action using patterned magnetic fields. - **Micro Coils vs. Micro Strips**: Micro coils are ideal but expensive; micro strips offer a cheaper/easier alternative for achieving directional force control. ## Counterarguments & Caveats - If the electromagnet on the robot's hat isn't used, the robot can still be guided magnetically. - Applying force with a probe risks the user not knowing the actual force applied to the cell. - Initial electromagnets create global fields, hindering the independent control of multiple robots. - Manufacturing micro coils or strips at the micro scale is noted as being extremely difficult and expensive. ## Methodology - **Electromagnet Array Setup**: Surrounding the workspace with electromagnets to establish the initial magnetic field for guiding the robot. - **Magnetic Feet Development**: Designing magnetic feet with different magnetic properties than the main body magnet. - **Soft Compliant Structure Use**: Employed as an end effector to measure mechanical properties by observing object deformation. - **Microscopy Integration**: Combining microscopy with a camera to observe deformation and calculate force based on known stiffness data. - **Patterned Coil/Strip Programming**: Programming patterned coils/strips to generate specific, directional forces to achieve independent manipulation control. ## Conclusions & Recommendations - The ultimate goal is to operate these microbots at the micro scale *inside* the human body. - If a medical need can be conceptualized, the microbots have the potential to address it. - The final call to action: *The only limit is your imagination.* ## Implications & Consequences - Microbots could allow surgeons to remove blood clots deep in the brain where current techniques struggle (as seen in Joe's case). - Targeted drug delivery can improve patient outcomes by achieving higher drug concentrations directly at a tumor site. - Microbots can enable less invasive biopsies by retrieving tissue samples internally. - Future microbots could have the full capability suite: onboard computers, cameras, intelligence, arms, and hands. ## Verbatim Moments - *"Microbots, microbots."* - *"The first thing you need to know about a micro robot is it's very small so we say its submillimetre dimensions."* - *"The only limit is your imagination."* - *"Microbots, microbots."* - *"This is an unscripted event in Joe's life in my life."*