Material research for wearable and implantable devices_Stanford University'
Tonight, I had the pleasure of virtually attending a seminar hosted by Stanford University. The first presentation immediately resonated with my own research interests in sensor design and fabrication.
🧠 Additively Manufactured Micro-Lattice Dielectrics for Multiaxial Capacitive Sensors
Speaker: Arielle Berman, PhD Candidate, Bao’s Group, Stanford University
Human skin enables us to interact with the world by sensing both normal and shear forces. Reproducing this dual-mode sensitivity in artificial systems is a longstanding challenge in soft electronics.
Key question:
Can we reliably fabricate sensors that detect both normal pressure and shear force, using a scalable method?
🔍 Current Limitations in Shear Sensing
Most existing shear sensors rely on:
- Complex fabrication processes
- Multiple lamination steps
- Planar lithography techniques
- Poor repeatability
These limitations make them impractical for large-scale or robust wearable applications.
🧩 3D-Printed Lattices: A New Direction
While 3D-printed lattice structures have shown promise in detecting normal pressure, they haven’t yet achieved consistent multiaxial sensing.
A key insight from the talk was that the microstructure of the dielectric layer has a significant effect on sensor performance—not just in magnitude but in the type of force detected.
🧪 Their Approach: CLIP-Based Fabrication
The team proposed a novel approach using Continuous Liquid Interface Production (CLIP) to create complex, fine-resolution lattice structures. This method enables:
- High repeatability
- Design freedom
- Tailored mechanical and electrical properties
By carefully engineering the dielectric micro-lattice, they demonstrated sensors capable of detecting both normal and shear forces with good sensitivity and reproducibility.
🌿 Texture Morphing with Soft Matter
Speaker: Siddharth Doshi
Surfaces are more than boundaries—they act as gateways to our environment.
Living organisms achieve dynamic control of surface texture using soft, responsive materials. This talk focused on the possibilities and challenges of texture morphing with soft matter systems.
🔧 Key Challenges:
- Encoding complex textures in a programmable way
- Achieving reversible, controllable morphing
- Maintaining material robustness under deformation
⚡ Transparent, Patternable, and Stretchable Conducting Polymer Solid Electrodes for Dielectric Elastomer Actuators
Speaker: Eunyoung Kim, PhD Candidate, Bao Group
Dielectric elastomer actuators (DEAs) are a promising class of cutaneous haptic devices, offering silent, fast, and compliant actuation.
💡 Types of Haptics:
- Electromagnetic motors
- Piezoelectric actuators
- Liquid crystal elastomers
- Dielectric elastomer actuators (DEA)
❗ Problem:
Most DEA electrodes are non-biocompatible, require protective layers, or are not patternable.
✅ Requirements for DEA-Compatible Solid Electrodes:
- Electrical: High conductivity
- Mechanical: Low modulus, thin profile
- Fabrication: Biocompatibility, transparency, and patternability
🧪 State-of-the-Art Limitations:
- PDMS/Carbon grease: Requires protective layer
- VHB4910/Liquid metal: Also requires protective encapsulation
- Other PDMS composites: Face trade-offs in conductivity and flexibility
🌟 Innovation:
A new P123DA/PEDOT:PSS solid electrode design shows promising:
- Transparency
- Patternability
- Biocompatibility
- Stretchability
🧬 In-Silico EIS Characterization of Supported Lipid Bilayers on PEDOT:PSS Electrodes
Speaker: Julian Mele, PhD Candidate
Explored the use of electrochemical impedance spectroscopy (EIS) to model and characterize lipid bilayer behavior on PEDOT:PSS substrates.
🧠 Electrochemical Performance of PEDOT:PSS Stimulation Electrodes
Speaker: Gerwin Dijk, PhD Candidate
Focused on the role of conducting polymers in therapeutic electrical stimulation, such as:
- Deep brain stimulation for movement disorders
- Spinal cord stimulation for chronic pain relief
🎯 Requirements for Long-Term Neural Interfaces:
- Sustained functional response
- High electrode stability
- No tissue damage over time
🧵 Biomimetic Design Approaches:
- Tissue-like materials: Soft, thin, hydrogel- or mesh-based electrodes
- Cell-seeded interfaces for bio-integration
🔍 Material Comparison:
- Conventional Platinum (Pt) electrodes
- Enhanced Pt-PEDOT:PSS electrodes
Material research for wearable and implantable devices_Stanford University'
