SlipStream™ Flow Cell Technology

SlipStream™ flow cell technology is a process by which CiDRA® Precision Services, LLC’s  plasma activated PDMS BioGasket™ technology and world class hard material precision machining expertise are married to produce laminated flow cells with unparallel optical and fluidic characteristics.   SlipStream™ technology is primarily used in the Life Sciences industry as consumable flow cells and as permanent flow cells within instruments.  With the ability to span microfluidic to macrofluidic flow regimes, to manufacture both large and small devices, and to produce flow cell channels with unparallel optical quality, SlipStream™ technology is ideal for high performance applications needing a low performance price tag. 

Years of development at CiDRA® Precision Services, LLC has led to amazingly simple and robust manufacturing processes.  The process involves some or all of the following steps:

  1. Machine Top and Bottom Glass Windows:   CiDRA® Precision Services, LLC leverages over a decade of expertise and infrastructure investment to produce holes, channels, chamfers or any other required feature in the top and bottom windows.   
  2. Clean Top and Bottom Glass Windows:  Both ultrasonic and plasma cleaning are used to produce pristine working surfaces.
  3. Cut BioGasket™ to the Desired Channel Shapes:  For most applications, flow channel shapes are cut in PDMS layers ranging from 25um to 700um thick using a micron resolution robotic cutting system. 
  4. Plasma Activate the BioGasket™:  Using state-of-the-art vacuum plasma cleaners and proprietary gas mixtures makes for a robust activation process.
  5. Laminate the Flow Cell Assembly:  Done in batch for cost effective production.
  6. Add Pressure & Temperature:  With pressures less than 100psi and temperatures less than 100°C, the infrastructure to complete the bonding reaction kinetics is readily available and inexpensive. 
  7. Add fluidic fittings:  Luer Loks, Nanoports, custom designed fittings or none at all.
  8. Inspection:  Inspect the flow cell for compliance with customer requirements using the latest technology vision systems and interferometers.

The details of manufacturing specific cells depend on the flow cell size, design requirements, production volume and cost targets.  In some instances,  we manufacture cells in large sheets and then dice them to final size.  This approach has the obvious advantage of scale.  In other cases, we precut and drill the glass windows and assemble each cell individually.

SlipStream™ Technology Advantages

  • Pristine Optical Characteristics:  Because SlipStream™ technology uses low temperature and pressure during the bonding processes, the top and bottom flow cell windows do not warp, dimple or discolor during assembly.  In addition, SlipStream™ does not use etching so it produces pristine flatness and surface roughness in the fluidic channels.  SlipStream™ is the only viable way to produce cost effective, flow cells made from difficult to deep-etch materials such as fused silica.
  • Many Material Choices:  SlipStream™ technology is the only technology that can use any combination of top and bottom window materials in the flow cell construction – not just CTE matched materials.  Flow cells can be manufactured from borosilicate glass, fused silica and quartz, silicon, sapphire, and some ceramics.  This allows ultimate flexibility to choose the best materials for application.
  • Streamlined Prototyping and Manufacturing:  No masks are required because SlipStream™ Flow cells use micro-robotic cutting to manufacture the channels.  As a result, the technology is ideal for prototyping and volume production alike.
  • Design Flexibility:  With micro-robotic cutting, a wide range of fluidic geometries can be created with little or no hardware changes.  It is as simple as loading a new CAD file.
  • Three Dimensional Constructions:  With low temperature and pressure bonding, SlipStream™ technology makes it easy to manufacture flow cells with complex, multilayer flow paths.

There are many technologies capable of producing laminated flow cells, most of which find their origins in the MEMS world.  The table below provides a high level comparison of the leading technologies.

Flow Cell Technology Comparison

 

SlipStream™

DRIE

HF Etching

Powder Blasting

Photosensitive Glass Etching (*)
Feature Size >50m >5um >5um >50um >20um
Channel Depth 25um - >1mm 0.1 - 500um 0.1 - 100um 25um - >1mm 25um – 1mm
Wall Angle >89.5 >89.5 >98 ~70 >98
Channel Surface Roughness (Ra) <2nm <2nm ~100nm 1um 1um
Materials Any Glass, Fused Silica, Silicon, SiC, AlN, others Borosilicate Glass,
Fused Silica, Silicon		 Foturan™
Bonding Technology Low Temperature/ Pressure High Temperature/Pressure
Warping During Bonding No Yes
(*)  Foturan has a medium level of autofluoresence, meaning its autofluoresence  is higher than borosilicate glass and PDMS.  See the table provided in flow cell materials page for a ranking of the autoflurosence of the materials CiDRA® Precision Services, LLC uses.               

 

 

SlipStream™ Flow Cell Specifications

Parameter

Specification
Optical Flatness (all surfaces) Less than 500nm/mm
Bottom & Top Plate Thickness 100um to 1cm
Top & Bottom Plate Thickness Tolerance Less than +/-20um
Top & Bottom Plate Parallelism Tolerance Less than +/-10um
Channel Thickness 25um to 700um
Channel Width 50um to >1cm
Channel  Dimensional Accuracy +/-20um
Standard  Gasket Colors Clear, White
Surface Roughness (Ra) for All Optical Surfaces <2nm
Scratch/Dig Within Clear Aperture 10um/20um
Maximum Operational Temperature 200°C
Maximum Pressure 100psi (*)
Maximum Size 2,000cm2

(*) Design dependent