AirJet Dispensing: Providing Solutions for Deposition of Conjugates and Blocking Reagents in Lateral Flow Assays

When it comes to lateral flow test manufacturing, conjugate and blocking deposition is typically done using a saturation process. This involves either soaking sheets (batch processing) or running web materials through a dipping tank (inline processing), followed by drying.

CONJUGATES

Glass fiber or polyester are typical materials used as conjugate pads. The variable surface characteristics of these materials combined with the difficulty of dispensing particulates make it difficult to use the small orifice dispensers that are often used for test and control line dispensing.

The AirJet is a unique dispensing technology ideal for quantitative and uniform dispensing of fluids with particulates. The AirJet is an aerosol dispenser similar to an artist's airbrush that is coupled with a syringe pump. Dispensing volume, line width and air pressure are all adjustable, allowing for the dispensing of finite lines on materials (figure 1.0) or for full coating/impregnation of the material (figure 2.0).

BLOCKING

The process of adding blocking reagents is also typically accomplished using soaking or dip coating methods. In this application the AirJet adds to the process control. Using a controlled dispense volume can minimize the variation seen due to uneven absorption of reagents.

CUSTOMER APPLICATION

For this application, the customer, a long-time producer of HCV/HIV and other IVD point-of-care lateral flow tests, required an in-line system in which the blocking process would be performed with spray coating. In addition, the customer wished to replace their former conjugate dispensing process with BioDot’s AirJet spraying technology. The in-line RR120 with Ultra-Lo Tension tracking, four AirJet 3000 channels, and two dry towers were used to meet the production volume demands and to accommodate the material’s low tensile strength when saturated. For each process, a series of two AirJet dispensers led to sufficient impregnation of the materials, and the Ultra-Lo Tension configuration of the system allowed for handling of thin web materials with lower risk of snapping and tearing.  It was found that moderate web speeds ( 25 mm/sec) were used.

This AirJet technology makes it possible to deliver a precise quantity of reagent to the pads and membranes while allowing for good control over spreading. Not only is this process more efficient than dip coating, but it also reduces the inherent variability found in some of the materials. In addition, it allows for faster drying, thus leading to increased throughput.

Our team of engineers and scientists can help you determine the specifications for dispensing conjugates and blocking reagents. Please contact us with any questions.

The process of adding blocking reagents is also typically accomplished using soaking or dip coating methods. In this application the AirJet adds to the process control. Using a controlled dispense volume can minimize the variation seen due to uneven absorption of reagents.

Our team of engineers and scientists can help you determine the specifications for dispensing conjugates and blocking reagents. Please contact us with any questions.