Immunochromatographic Assays also known as Lateral Flow Tests or just Strip Tests are immunoassays performed on an easy to use strip format. This strip format provides numerous benefits to both the user and the manufacturer. While there are a number of variations of this Point of Care (PoC) technology, they all function using the same basic principles and materials. To date there is an ever growing range of assays in clinical, environmental, veterinary, agriculture, bio-defense, etc… Benefits of this format are:

  • Ease of use
  • Requires relatively small amount of sample
  • Adequate level of sensitivity
  • Ease of manufacture in large scale
  • Stability of the final product at room temperature (shelf life)
  • Ease of implementation with a reader technology
  • Ease of approval by regulatory instances (format well known by the market)
  • Relatively inexpensive to manufacture

LF_Assembly

 

Manufacturing Schemes

Traditionally, a lateral flow immunoassay device is assembled with a variety of materials and reagents. Typical components are a plastic backing card, membrane, sample pad, absorbent pad, conjugate pad, and possibly a wick and/or cover tape. Reagents are dispensed or coated, each material is laminated to a backing card and the card is singulated into individual test strips. Manufacturing can be completely manual, “Batch” style process, completely automated, “In Line Continuous” process, or a “Hybrid” of the two.

BATCH PROCESSING – The batch process starts with sheets or rolls of each component. Each material goes through its own process independently (dispensing, drying, etc…) and then once prepared, the final test is assembled and cut. The batch processing scheme has the lowest cost of equipment but requires much higher labor cost.

  • Test/Control/Conjugate Dispensing – BioDot’s XYZ3060 or ZX1010 are used for positioning of the test, control and conjugate reagents. BioDot’s proprietary BioJet, AirJet and FrontLine dispensers provide precision non-contact and contact dispensing capabilities. Dispensing can be performed on pre-laminated cards or solitary materials. 
  • Master Card Lamination- BioDot’s LM5000 (clamshell laminator) is a manual device used to assemble precut membrane, conjugate pad, absorbent pads and plastic backing with precision overlap to create a laminated master test strip card.
  • Cover Tape Lamination – The LM5000 can be used to manually laminate the cover tape (a second LM5000 and/or additional nest is required).
  • Master Card Cutting – The CM4000 Guillotine cutting module cuts laminated master cards into individual test strips. This robust cutter is designed to provide precision cuts and maximum flexibility for the R&D and manufacturing environments.
  • Assembly – Manual assembly of cut strips into the cassette. BioDot’s AR3000 assembly roller is uses pressure to close the cassette. 

HYBRID PROCESSING (roll stock membrane lamination) – The hybrid manufacturing process is a combination of the manual batch processing steps and automated in-line machines. This approach provides some of the automation benefits like improved quality and material cost reduction of fully automated processes but with a smaller capital costs.

  • Membrane Pre-lamination – Membrane is supplied in a roll format and must be cut and laminated to the plastic backing card before dispensing. The LM8010 takes a roll of membrane and laminates it onto adhesive lined plastic backing cards. Auto-tracking and guides accurately position the materials and pinch rollers complete the lamination. Automating this step saves on material costs and increases product quality. After laminating the web is cut back to individual cards.
  • Test/Control/Conjugate Dispensing – Individual membrane laminated cards are presented to BioDot’s XYZ3060 or ZX1010 for dispensing test/control lines. BioDot’s proprietary BioJet, AirJet and FrontLine dispensers provide precision non-contact and contact dispensing capabilities.
  • Master Card Lamination – BioDot’s LM5000 (clamshell laminator) is used to assemble the conjugate pad, absorbent pads and membrane with plastic backing to create a laminated master test strip card.
  • Cover Tape Lamination – The LM8020 is used to laminate the cover tape(s) onto the master card. The tape(s) is supplied in roll stock and the master cards are manually fed. The cover tape is positioned through fixed guides and custom profiled rollers assure proper adhesion of the materials. After lamination the roll is then cut back into master cards. The LM8020 can also be used to assembly the absorbent and wicking pads to the master card. Any reagent processing would need to precede this step.
  • Master Card Cutting – The CM4000 Guillotine cutting module cuts laminated master cards into individual test strips. This robust cutter is designed to provide precision cuts and maximum flexibility for the R&D and manufacturing environments.
  • Assembly – Two options are available here: 1. Manual assembly per batch processing or 2. The use of the JOT assembly system using manual or automatic feeding of cut strips and cassette bottom and top. The JOT machine would automatically place the strip into the bottom cassette and the top cassette onto the bottom with a final press to complete the assembly. The placement of parts is under vision control.

IN LINE PROCESSING- An In Line manufacturing process starts with all materials in roll format. This manufacturing scheme offers the highest throughput and quality control. Typically equipment in this scheme is designed to meet the specific needs of an application. This approach allows multi-tasking between dispensing and impregnation applications, and quality control monitoring.

  • Test/Control/Conjugate Dispensing and Drying – BioDot’s RR120 is a reel-to-reel system designed for web dispensing/coating and drying. For test/control line dispensing BioDot’s proprietary BioJet and FrontLine dispensers provide precision non-contact and contact dispensing. For conjugate and blocking applications BioDot’s AirJet technology is available. Web tracking, vision inspection, part, marking, dip coating and drying are all available on the system. Processed materials are rewound onto a core that is compatible with the in line lamination equipment.
  • Slitting – A slitting module is used to cut processed webs down to narrower widths for lamination.
  • Master Card Lamination – The LM9000 lamination machine brings together rolls of processed test strip materials for continuous lamination on one machine. Each material has a payout roller (with liner take up if needed) and guide to assure accurate alignment along the plastic backing. Profiled rollers make sure there is good adhesion to the backing. Once each layer has been laminated the reel can be cut into master cards or can be re-rolled onto a larger diameter take up reel.
  • Master Card/Roll Cutting - Cutting the laminated cards into individual strips can be done with guillotine cutting or rotary cutting. For guillotine cutting rolls or master cards can be used to feed to a single blade cutting system. Rotary blade cutting is available for master cards and utilizes multiple blades that simultaneously cut the entire master card.
  • Assembly – The JOT system is a machine that can be configured for fully automatic assembly of the lateral flow device from the strip cutting operation to final assembly of the device. The master laminate can be magazine fed or roll fed to the strip cutting with pick and place to a conveyor feed to the assembly operations. The cassette parts are bowl fed and placed onto an assembly conveyor for vision controlled pick and place operations.

 

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