Cartridge & Consumable Design

• Lyospheres
• Encapsulated lyospheres
• Dried down suspended reagents
• Loose powdered reagents

• Foil Blisters
• Polymer Blisters
• Covered Reservoirs
• Ampoules
• Bags
• Glass or polymer tubes

Liquid/Reagent Mixing: Controlling the mixing dynamics of the liquids and reagents with sample to ensure homogenous distribution.

Liquid Mixing Methods:

• Shuttle mixing – via differential pressure
• Vibration / Sonication
• Stirring with magnetic bars
• Static Mixing through channel shape eg: Split height herringbone
• Aspiration and Dispense via Pipette

Liquid Metering / Measurement: Controlling the volume of the stored or introduced liquids in the consumable for the correct reagent dilution, flushing, separation and mixing of the inputs and/or stored reagents.

Liquid Metering Methods:

• Overflow Reservoir Volume
• Differential pressure – known pressure drop
• Surface energy modification and/or selection eg: digital fluidics
• Hydrophobic filters
• Air Displacement Pipettor and pipette
• Peristaltic Pump
• Flowmeter

Liquid Movement: Controlling the stored or introduced liquids in the consumable for the dilution, flushing, separation and mixing of the inputs and/or stored reagents, via microfluidic or macrofluidic channels and reservoirs formed through film on moulds or lamination, or through sterile bags and tubes.

Liquid Movement Methods:

• Valves – pancake, pinch, check, pressure actuated
• Differential pressure
• Surface energy modification and/or selection
• Hydrophobic filters
• Robotic Pipettor
• Peristaltic or Positive Displacement Pumps

Channel Formation Methods:

• Thin film welded onto moulded substrates with channels – Thermal, Ultrasonic, Laser
• Layered / Laminated films formed with adhesive or welding
• Polymer tubing and connections

Sample Inputs: Controlling the means of sample introduction to the consumable and measurement to suit the onboard reagents through separation, metering or mixing to ensure homogenous distribution.

Sample Introduction Methods:

• Direct Liquid – eg: Blood, Saliva, Urine, etc – into measurement chamber
• Pre-processed – eg: swab into diluent solution
• On Consumable Swab – eg: swab into input chamber, and then flushed with onboard liquid
• Sample filtered to remove contaminants or non-soluble components
• Sterile Bag (Blood, Saline, etc)

Every consumable will experience similar phases of development, however the costs of the phases will be based upon the complexity of the ultimate consumable design.  What is essential is planning for the costs of development, and the associated costs of ramping up the volumes required for development from Prototype, to Production in volume.   Associated with each of the phases of development is the maturity of the manufacturing process steps at that phase, and the resultant comparative cost of the consumable. For Example, as the design and assembly maturity improves, the production yield improves:

• Prototype – 70%
• Alpha – 80%
• Beta – 85%
• Pre-production – 90%
• Early production – 90-95%
• Stable production – 99%

However, as the production volume goes up, process automation becomes cost effective, and consumable unit cost reduces through volume purchasing of raw materials, and reduction of labor in the process.

Used Consumable Disposal: the consumable is assembled from polymers and metals that can be re-cycled – generally, most components used in a biological investigation use will become biological waste and incinerated.  However the consumable will be designed to seal in all components introduced and used in the assay.

Sealing Methods:

• Hydrophobic Filters (HPF)  – to control fluid flow/metering while preventing egress of all reagents and biological materials in the fluid
• Welded channels – tested through pressure leak-down during assembly
• Interference fit lids / caps for the sample input 
• Gaskets used in all interfaces where differential pressure used – with HPF separation as required
• Tube welding and sealing