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The standard method for developing and validating Biomagnetic separation processes is sampling the supernatant at different times. This sample is usually measured using a spectrophotometer. Bead concentration is determined by selecting the right wavelength to avoid interferences with the biomolecules presents in the buffer and comparing it with a calibration curve. The separation time is selected when the number of beads approaches zero. Magnetic susceptibility using the fundamental frequency or some of its harmonics has recently been proposed as alternative.

Free PDF guide: "The Basic Guide  for Monitoring Biomagnetic Separation Processes"

One of the problems with these approaches involves the sampling method, because the concentration differs at different points of the working volume. How and from where the sample should be taken is a controversial question.

Obtaining real-time information about the entire working volume (ml at the laboratory, liters at production) is a suitable option for checking the evolution of the process. To achieve this goal without interfering with the Magnetic Bead Separation process, optical measurements seem to be a better candidate than magnetic techniques.

This article explains the advantages of monitoring Magnetic Bead Separation processes. If you are interested in knowing more about this innovation download our free basic guide for monitoring Magnetic Bead Separation processes:

The starting suspension, in which the magnetic beads are homogenously distributed, is opaque (unless concentration is very low), however when the solid phase is separated, the buffer becomes transparent. Measuring the light transmitted through the vessel gives a real-time measurement of the evolution of the Magnetic Bead Separation process. When constant magnetic force is used, the beads move radially from the center, so that measuring transmitted light gives a good picture of the process evolution.

This method can be used with different wave lengths, using spectrophotometry if necessary. It is likely to improve accuracy, however, the system needs to be tailored to the bead/particle and suspension. The correct wavelength for a 50 nm magnetic particle is not the same as that for a 1 micron magnetic bead. A simpler approach, measuring white light transmittance, has proven effective for a wide range of diameters and buffers.

Using the constant magnetic force of Advanced Magnetic Bead Systems makes it simple to optically monitor the evolution of the process. Also, as you will see in later chapters, these systems make it easy to interpret the information obtained and use it to obtain information about the process and/or control its performance.

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FREE Download: Basic guide to magnetic bead cell separation

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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