Precision Fluid Dispensing Systems for Point-of-Care Diagnostic Applications

How to Improve Cycle Time, Volume Accuracy, and More

Point-of-care (POC) diagnostics is a crucial field of research in the medical industry since these POC devices help doctors make critical decisions and help patients monitor their health. These devices can range from HIV tests to blood tests and, more recently, COVID-19 tests.

Nordson EFD provides fluid dispensing equipment that helps manufacturers meet and exceed requirements for quality and product consistency that is essential in life sciences. In this blog post, we will share details about several diagnostic applications where our fluid dispensing products increased production, improved accuracy, and more.

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DIAGNOSTIC READERS

APPLICATION #1: ADHERING PARTS OF BLOOD GAS ANALYZERS

-Fluids Used:

• UV-cure adhesives

-Application Requirements:

A medical manufacturer needed greater accuracy when dispensing a UV-cure adhesive to assemble blood gas analyzers. They were also looking for an automated solution, having previously used benchtop dispensers to assemble the readers by hand.

-Dispensing Solutions:

• PICO XP Jetting Systems

The production of most diagnostic analyzers is meticulous and requires precise dispensing operations to ensure correct functioning of the end product. With this in mind, we recommended the PICO XP jetting system because of the extreme accuracy and reliability it offers.

This jetting system allowed the manufacturer to accurately dispense lines of UV-cure adhesives along two parts to bond them together. As the next generation product to our standard PICO Pµlse, the PICO XP provides better, more repeatable deposit tolerances. It self-adjusts to maintain micron-level stroke of the jetted volume over time, staying closer to the initial dispensing parameters and making this our most accurate jetting valve.

 

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APPLICATION #2: ADHERING PARTS OF COVID-19 DIAGNOSTIC READERS

-Fluids Used:

• UV-cure adhesive and cyanoacrylate mix

-Application Requirements:

A healthcare technology company needed a solution for accurately dispensing a mix of UV-cure adhesive and cyanoacrylates to assemble a new COVID-19 diagnostic reader. The parts needed to be bonded together properly in order for the reader to accurately read the inserted test strips.

-Dispensing Solutions:

• 752V Diaphragm Valves
• EV Series Automated Fluid Dispensing Systems
• RV Series Automated Fluid Dispensing Systems

The 752V diaphragm valve features an open/close stroke adjustable from 0.13 mm to 0.64 mm to produce a fast response and positive shutoff. This helped the manufacturer reduce fluid waste when dispensing. Its wetted parts are made from an inert ultra-high molecular weight (UHMW) polyethylene which made the valve suitable for dispensing the fast-curing cyanoacrylate mix.

 

Due to the geometries of the COVID-19 diagnostic reader, we recommended both our EV Series and RV Series automated dispensing systems. While our EV robot could dispense the UV-cure adhesive and cyanoacrylate mix along X, Y, and Z coordinates of the substrate, a fourth axis was needed to rotate 360° around the part and dispense in hard-to-reach places such as where the test strip would be inserted.

 

Both robots include vision, meaning they have either a pencil or CCD camera that displays an on-screen preview of the dispensing path to make programming complex patterns easier. For this medical application where reliability was essential, the vision system was able to provide assurance of correct part alignment using fiducial recognition.

 

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TEST STRIPS

APPLICATION #1: DISPENSING VARIOUS REAGENTS ONTO TEST STRIPS

-Fluids Used:

• Various reagents

-Application Requirements:

This medical manufacturer needed a different robot from what had been used prior to provide easier setup and better software. The dispensing of reagents onto test strips needed to be accurate to avoid any false positive/negative test results.

-Dispensing Solutions:

• PROPlus Series Automated Fluid Dispensing Systems

For this application, we recommended our PROPlus Series robot. This is our most sophisticated and advanced automated dispensing system that is designed for simplified usability. It features our unique DispenseMotion™ software that seamlessly integrates with the camera. The high-definition CCD smart camera features a global shutter to eliminate any blurriness or distortions when the robot is operating. It also features laser height detection (see image below) to identify height variations and self-adjust accordingly for superior accuracy.

This provided a high level of accuracy when dispensing sub-microliters of fluid onto each conjugate pad of the test strip. It was crucial that deposits were accurate so that each fluid was dispensed onto the correct pad to avoid overflow and provide an accurate test result.

 

As we can see in the lateral flow of a test strip below, the chemistries must be dispensed only on certain sections of the test strip. This manufacturer had separate test strips for COVID-19, glucose, blood, and more. It was vitally important that the fluid volume be controlled and applied only to particular sections. That way, when the blood or test sample is added to the sample pad, the right antibodies and antigens are latching onto the sample to provide an accurate test result.

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APPLICATION #2: DISPENSING ONTO BLOOD TEST STRIPS

-Fluids Used:

• UV-cure adhesives
• Reagents

-Application Requirements:

This medical technology manufacturer needed a faster solution to keep up with an increase in production and market demands.

-Dispensing Solutions:

• PICO Pµlse Jetting Systems

Although their previous process included our 754V aseptic valves, xQR41 MicroDot™ valves, and Ultimus V fluid dispensers, an exponential increase in demand required them to switch to a jetting solution. We can see in the video below how eliminating the Z-axis greatly speeds up the dispensing process up to 1000Hz (deposits per second) continuously. Jetting is also quicker to set up since it doesn’t require programming where a tip would be coming down onto a substrate, eliminating the risk of bending tips and damaging substrates.

Our PICO Pµlse jetting system was able to increase their blood test strip production with its ability to dispense micro-deposits in a fast and repeatable manner, vastly improving throughput. In the future, we will recommend our new PICO XP jetting system, which provides superior repeatability for longer periods regardless of valve stack temperature changes.

 

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Conclusion

Overall, Nordson EFD provides reliable precision dispensing solutions designed to help manufacturers meet the strict quality control regulations in the life sciences industry. We also work with a network of skilled machine builders and integrators who design automated solutions for the growing diagnostic reader and test strip markets.

If you would like to discuss your next point-of-care diagnostics application with an experienced fluid dispensing expert or get a recommendation on our outside team of machine builders, don’t hesitate to email us at [email protected].

 

 

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