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Control Your Quality: Real-Time Biomagnetic Separation Process Monitoring

Quality Control is one of the key issues at IVD-kits manufacturing. To assure the lot-to-lot consistency is critical to have consistent results when the reagents are used in the analyzers. To decide where to place the quality Control points is one of the more critical decisions, with large repercussion in the kits manufacturing costs. A single control point at the end of the process implies that a ‘no-pass’ result would force the whole batch to discard, wasting all the time and resources invested on it. Having too many QC along the different process steps would greatly increase the costs, as tests usually involve intensive labor and/or expensive analysis techniques.

For CLIA IVD-kits manufacturing (or any products involving magnetic beads), we can take advantage of the biomagnetic separation process itself to check the magnetic beads behavior. As usually there are many separation steps (several washing before and after each conjugation), having them optically monitored provide inexpensive QC points along the whole process.

Reference curve resized 600

If you want to know everything about monitoring biomagnetic separation processes in real time, download our free guide about this topic:

FREE Download: Real-time monitoring of biomagnetic separation

The dynamics of the magnetic beads are very different when the beads are well re-suspended and when clumps are formed. Basically, if you have clumps, the magnetic separation is equivalent to having beads of larger diameter and the process is faster. Unfortunately, the usual SOP (Standard Operation Procedures) only checks visually if the separation is complete at the defined separation time. Even if the clumps accelerate the separation time, it would be impossible to detect by eye-sight at the final specified time, as both suspensions would be crystal clear.

Taking advantage of advanced biomagnetic separation

By recording the transmitted light across the vessel, we can monitor the transparency changes during the separation process, showing the described sigmoidal-like behavior. As shown in the figure (real case), using the same suspension in the same SEPMAG® Q1L, the time is reduced by almost a 30% when beads have become aggregated due to a bad storage protocol.

We can take advantage of this behavior to stablish quality control protocols that can indicate re-suspension problems during the biomagnetic separation steps. A reference curve can be generated for each step and the experimental curve obtained during the process. Any significant deviation from it would be an early indicator of quality problem. That may allow stopping the batch and/or take corrective actions before going ahead with the following steps, avoiding the cost and delays to detect the problem and later on the whole manufacturing process.

QC curves resized 600

The optical monitoring of the biomagnetic separation process gives us much more information than just the separation time. Besides giving us a methodology to objectively determine this parameter –i.e., not dependent on subjective eye-sight-, the measured curve would be an early alert for many quality control problems. Its shape would change not only as a result of the clumps formation, but also viscosity or concentration, or if the magnetic beads have different diameter or content of magnetic content.

When the entire process is monitored rather than separation time alone, Quality Problems can be identified more quickly. Deviations from the reference curves may reveal numerous production problems (aggregation, incorrect bead characteristics and incorrect concentration) that can be detected during the Biomagnetic Separation step. This means corrective actions can be taken sooner, thus reducing costs.

In future documents we will discuss with more detail how different production problems affect the optical curve, so that the reader can have a basic guide to detect the rooth cause of the non-conformity of the batch.

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Lluis M. Martínez | SEPMAG Chief Scientific Officer

Founder of SEPMAG, Lluis holds a PhD in Magnetic Materials by the UAB. He has conducted research at German and Spanish academic institutions. Having worked in companies in Ireland, USA and Spain, he has more than 20 years of experience applying magnetic materials and sensors to industrial products and processes. He has filed several international patents on the field and co-authored more than 20 scientific papers, most of them on the subject of magnetic particle movement.

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