Glass Microfluidic Chips: When and Why

Why use glass?

• Outstanding chemical resistance — inert to almost all solvents, acids and bases, where polymers can swell or craze.
• Excellent optics — high transparency and very low autofluorescence, ideal for sensitive fluorescence and UV work.
• High-pressure capability — rigid and strong, suited to high-pressure flows.
• Well-defined surface chemistry — a stable silanol surface for reproducible coatings and electro-osmotic flow.
• Thermal stability — tolerates high temperatures and harsh cleaning.

How glass chips are made

Channels are typically patterned by photolithography and wet or dry etching, then a second wafer is bonded on top — often by high-temperature fusion bonding or anodic bonding — to seal the channels. The result is a robust, fully inorganic device. Fused silica is used where the best UV transmission and lowest fluorescence are needed.

The trade-offs

• Cost and lead time — etching and bonding are slower and more expensive than moulding plastic.
• Not for high volume — glass does not mass-produce as cheaply as injection-moulded thermoplastics.
• Brittle — can crack under mechanical shock.

Glass vs polymer: how to choose

Choose glass when chemical compatibility (especially organic solvents), high pressure, or the very best optical performance are non-negotiable — common in analytical chemistry, electrophoresis and demanding droplet work. Choose a polymer when cost at scale, disposability or toughness matter more. Many teams prototype in glass or PDMS and move to thermoplastics for production. Compare options on our materials page.

Frequently asked questions