Advantages and Limitations of Lamination & Injection Molding

Lamination

Microfluidic cartridges are laminated with double-sided pressure sensitive adhesives (PSA). Laser or die-cutting techniques create microfluidic channels and interconnect holes in different layers of material. The depth of the channel in our devices can be as small as 25 μm or as large as several millimeters.

Advantages:

  • Quick turn-around time for rapid prototyping and fluidic functionality tests. With laser cutting, no special tool is required. Parts can be cut and laminated within the same day.
  • Different materials (filters, plastic, metal, glass) can be integrated into one device.
  • Excellent channel thickness control (within 5-10%) for devices requiring optical detection.

Limitations:

  • For optimum performance, feature width should be 400 μm or larger.
  • Micro fluidic flow characteristics in narrow channels may be affected by uneven edges of laser cut PSA.
  • When laser cutting is used, low molecular weight polymer residues can be redeposited at cut edges and may interfere with particular bioassays. Special cutting and cleaning procedures are needed to ensure assay compatibility.
  • To ensure assay functionality, early initiation of material selection and testing is critical.
Laminated Parts
COP Slides

Injection Molding

Microfluidic devices are injection molded and channels are sealed with heat lamination, ultrasonic welding, or laser welding.

Advantages:

  • High accuracy and reproducibility of plastic parts.
  • Ability to incorporate features as small as 50 mm into the parts.
  • 3-D features can be incorporated into the design.
  • Edges of the microfluidic channels are very smooth.

Limitations:

  • Difficulty in bonding materials of different types.
  • Bonding methods can be difficult to optimize and control.
  • To ensure assay functionality, early initiation of material selection and testing is critical.
  • Higher cost and slower turnaround time (weeks to months) than those required for laminated devices (days to weeks).

Image of Injection Molding for Protein Microarray

Protein Microarray