Multiplexed Immunoassay System Gains New Shutter

A long-life shutter mechanism has been developed for a new immunoassay system.

The shutter assembly has extended the mechanism's life from one million to over 10 million operations. Pronostics Ltd. has developed a range of revolutionary medical diagnostic products based on its core multiplexing technology, UltraPlex, which enables barcoding at a molecular level so that large numbers of biologic assays can be undertaken concurrently in a single container. This new technology, which is easier and cheaper to use than existing chip-based array technologies, drastically cuts the cost and time of performing diagnostics in hospital laboratories.

By attaching individual test molecules to metal microparticles, which are uniquely identified by physical barcodes, multiple tests may be tracked and analyzed simultaneously.

The assays are carried out in industry standard 96-well plates with liquid handling being performed by the UltraPlex SmartStation robotic system. Each well contains microparticles coated with the capture antigens and serum from one patient. The captured antibodies on the surface of the microparticles react with target antibodies in the serum and imprison them onto the surfaces of the microparticles. In the final stage of the assay, samples are automatically analyzed under a powerful microscope first using "white” light and then switching to high intensity white light from below the plate. The assay plate is then transferred to the UltraPlex SmartReader where the microparticles are decoded and their fluorescence levels measured to identify the disease.

Each light source is fitted with a shutter mechanism to enable the light to be selected or obscured. Due to the frequency of the shutter opening and closing, the mechanism quickly wore out. Looking for a company to provide it with the engineering resources to develop a more robust and "drop-in” solution, Pronostics chose Emessem Solenoid (Woking, UK).

Emessem Solenoid first needed analyze the shutter mechanism and its interaction with the light source and light tubes. The company also had to determine the nature and detail of the power supply driving the actuator within the shutter mechanism and the connections needed to integrate the shutter to the microscope. Once this had been achieved, Emessem Solenoid began the task of specifying the performance requirements of the assembly. This included the operating speed and stability of the shutter, the heat dissipation characteristics of the assembly, and light attenuation.

The company also needed to focus on the operating life of the shutter mechanism, electrical power consumption, and vibration characteristics. Key to the success of the project was the selection, adaptation, and manufacture of a suitable rotary solenoid to drive the shutter mechanism.

As part of the Magnet-Schultz Group, a solenoid manufacturer, Emessem Solenoid was in a unique position to develop the ultimate solenoid for the mechanism. Having completed its development, Emessem Solenoid then designed the assembly parts. Prototypes were manufactured before final testing was carried out to assess functional performance and longevity.

"Emessem Solenoid have done a magnificent job in developing the new shutter systems,” said Chris Savory, European sales manager at Pronostics. "Previously we were using an [U. S.] manufactured shutter which was not only very expensive but also wore out very quickly. Emessem Solenoid's new shutter is an excellent alternative, providing ten times the longevity and costing substantially less.” Emessem Solenoid is maintaining a file of its shutter innovation to support further development should greater levels of performance be required






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