Designing Screen Printed Electrodes for Functionality and Commercialisation
Introduction
If you're beginning work with screen printed electrodes (SPEs), one of the most effective starting points is to use a proven, off-the-shelf electrode before investing in a custom design. This allows you to validate your assay quickly, reduce early-stage risk, and build confidence in your electrochemistry before committing to manufacturing decisions.
A strong starting point is exploring commercially available electrodes such as:
https://shop.zimmerpeacock.com/en-gb/collections/bare-electrodes
Using these platforms helps you focus on what truly matters early on: assay development, signal quality, and reproducibility — rather than immediately tackling manufacturing complexity.
Understanding the SPE Architecture
Screen printed electrodes are fundamentally layered systems, consisting of:
- Substrate (base material)
- Conductive inks (working, counter, reference electrodes)
- Conductive tracks (sometimes enhanced with silver)
- Insulator (defining exposed electrode areas)
🔬 Each layer is printed and cured sequentially, meaning design choices directly influence both performance and manufacturability.
Substrate Selection: Proven vs Experimental
Your substrate choice underpins both reliability and scalability.
Recommended Materials
✅ PET (Polyethylene terephthalate)
- Industry standard (e.g. glucose strips)
- Highly scalable
- Commercially validated
✅ Polyimide
- Flexible and thin
- Ideal for wearable sensors
Less Suitable Options
⚠️ PVC
- Risk of plasticiser leaching during curing
⚠️ Paper
- Ink absorption leads to poor conductivity and distorted signals
⚠️ Ceramic
- High quality but limited scalability and higher cost
💡 Practical Insight: PET remains the lowest-risk option for commercial development.
Electrode Materials: Function vs Cost
Material choice must balance electrochemical performance with commercial viability.
Key Options
| Material | Advantages | Limitations |
|---|---|---|
| Carbon | Low cost, scalable | Lower conductivity |
| Gold | Excellent for biomolecule binding | High cost (~€0.50 per electrode) |
| Platinum | Ideal for oxidase-based assays | Expensive |
💡 Key Insight: Carbon is typically the best commercial choice — unless your chemistry specifically requires gold or platinum.
Advanced Materials: When and How to Use Them
- Graphene inks → lose structure, act like graphite
- Nanoparticles → best applied as surface coatings
- Carbon nanotubes / MXenes → more effective as post-processing
🔬 These materials are powerful but should generally be applied after printing, not incorporated into bulk inks.
Rethinking the Reference Electrode
Silver/silver chloride (Ag/AgCl) is common — but not always necessary.
Real-World Insight
✅ Many commercial biosensors (e.g. glucose strips) do not use Ag/AgCl
✅ Instead, they rely on redox mediators (e.g. ferricyanide)
💡 This enables:
- Fewer print steps
- Lower cost
- Simplified manufacturing
Do You Really Need an Insulator?
In research, insulators are common. In commercial products — less so.
Alternative Strategy
✅ Use adhesive layers or tapes to:
- Define fluid flow (microfluidics)
- Act as insulation simultaneously
📌 This reduces:
- Manufacturing steps
- Complexity
- Cost
Electrode Size: A Critical Commercial Lever
Electrode size directly impacts both cost and throughput.
Why It Matters
- Larger electrodes = more material usage
- Larger formats = fewer units per sheet
| Electrode Type | Relative Cost |
|---|---|
| Large R&D SPE | ~4× higher |
| Optimised SPE | Baseline |
✅ Smaller electrodes:
- Improve manufacturing efficiency
- Reduce cost per unit
- Enable higher production throughput
💡 Best Practice: Start with commercially realistic dimensions early — not as a later optimisation.
Think in Arrays, Not Individual Devices
SPEs are manufactured in sheet formats (arrays).
Benefits of Sheet-Based Thinking
✅ Easier automation
✅ Better positional control
✅ Higher throughput
⚙️ Early singulation introduces:
- Loss of positional data
- Increased variability
- Process inefficiencies
📌 Golden Rule: Keep electrodes in arrays until the final stage.
Connector Design: Follow the Industry Standard
Consistency improves compatibility with instrumentation.
Recommended Dimensions
- Total width: ~7.2 mm
- Connector width: 1.5 mm
- Pitch: 2.54 mm
- Length: ~4 mm
✅ Layout convention:
- Working electrode → centre
- Reference → right
- Counter → left
Feature Size and Manufacturability
Fine features increase risk in screen printing.
Practical Limits
- <100 µm → not suitable
- ~200 µm → possible but difficult
- ≥500 µm → reliable
✅ Millimetre-scale designs:
- Improve yield
- Simplify manufacturing
- Reduce variability
Reproducibility: The Foundation of Commercial Success
Even the best assay fails without consistency.
Key Challenge
- Variability in electrode area leads to signal variability
✅ High-quality SPEs should deliver:
- Low relative standard deviation (RSD)
- Consistent electrochemical responses
- Reliable calibration
Practical Takeaways
✅ Smart Development Approach
- Start with off-the-shelf SPEs before customisation
- Validate assay performance early
- Avoid premature design complexity
⚙️ Design for Manufacturability
- Use PET substrates where possible
- Minimise printing steps
- Follow standard connector layouts
🔬 Performance Considerations
- Choose materials based on chemistry AND cost
- Keep designs within manufacturable feature sizes
- Prioritise reproducibility over peak performance
📌 Commercial Mindset
- Design for scale from day one
- Think in arrays, not individual sensors
- Minimise materials and process steps
Closing Thoughts
Designing screen printed electrodes is not just about achieving a working signal — it is about building a system that can be reliably manufactured, scaled, and commercialised.
Starting with proven electrode platforms allows you to focus on the assay, gain confidence in your approach, and make informed decisions when moving towards custom designs.
If you are developing a biosensor or electrochemical device and would like expert guidance on scaling from concept to production, you can start a conversation here:
https://www.zimmerpeacock.com/contact
Hashtags
#Electrochemistry #Biosensors #ScreenPrintedElectrodes #Diagnostics #MedTech #SensorDesign
