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Optical monitoring of Biomagnetic Separation: how to parameterize the process

Validation is a mandatory requirement at IVD-kits manufacturing. The lot-to-lot consistency is critical to assure consistent results when the reagents are used in the analyzers. The key to have an efficient and cost-effective QC protocol would be having the right number of test points, and whatever possible, use existing techniques not requiring intensive use of manpower.

Advanced Biomagnetic Separation systems have recently incorporated monitoring systems to record the suspension transparency changes. By recording the transmitted light across the vessel, we can monitor the transparency changes during the whole separation process. The resultant curves give a quantitative value of the transparency at the end of the process, and also show how it changes since the vessel is introduced in the magnetic separation rack.

Any change of the properties of the magnetic beads (diameter, magnetic charge), the buffer (viscosity, ionicity, beads concentration) would affect the separation behavior. Any deviation from the expected curve can be used as an alarm. It would allow stopping the batch before incurring in additional costs and/or make the corrective actions when possible.

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

The importance of having well-defined conditions

If the Biomagnetic Separation System has well-defined conditions (i.e. homogenous force), the recorded curves will not only indicate that something is wrong, but also help identify the specific problem. When using a constant magnetic force in all the working volumes, the opacity versus time curve typically hasa sigmoidal shape. The curve can be parameterized just by the two values that define this curve: the exponent p and the time t50.The first reflects the ‘steepness’ of the curve and the second reflects the time it takes to reach 50% of the difference between the maximum and minimal opacity. These two parameters change on a different way depending on what different magnetic bead (diameter, % magnetic content, magnetic material) or the suspension (buffer viscosity, beads concentration, ionicity) characteristics vary.

On a typical example, the changes in the concentration would affect the curves modifying both the exponent p and the t50. The biomagnetic separation is a cooperative behavior where the beads interact between them through magnetic dipolar interaction (overcoming the thermal agitation). The higher the concentration the nearer the magnetic beads would be to the nearest neighbor. As a consequence, diluting the sample slows down the separation. This behavior is reflected in the transparency changes by a lower is p (the curve is less ‘stepper’) and a higher t50 (slower separation) for diluted samples when compared with the original suspension.

Conductive nanocomposite particles serve as electrochemical biosensors

Oxidative stress has been reported to be a significant aspect in the development of several pathologies, including atherosclerosis and diabetes mellitus. In addition to being the byproduct of a number of oxidases found in biological systems, hydrogen peroxide can be utilized as an effective indicator of oxidative stress. As such, several methods have been developed to detect its presence.

Real-Time Process Monitoring for Biomagnetic Separation

The validation of each single production batch is a mandatory requirement at IVD-kits manufacturing. The lot-to-lot consistency is critical to assure consistent results when the reagents are used in the analyzers.

Since many steps are involved in the production process, the placement of 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 may seem cheap, but it implies that a ‘no-pass’ result would force the whole batch to discard, wasting all the time and resources invested on it. The other solution, having many QC along the different process steps would greatly increase the costs, as tests usually involve intensive labor and/or expensive analysis techniques. The key to have an efficient and cost effective QC protocol would be having the right number of test points, and whatever possible, use existing techniques not requiring intensive use of manpower.

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 aremany separation steps (several washing before and after each conjugation),havingthem monitored provide inexpensive QC points along the whole process.

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

To do it, however, we should update the way that Biomagnetic separation steps are usually validated. In many cases, these processes are validated solely by separation time. The technician checks by eye-sight the transparency of the suspension after the defined separation times, and if he/she found it OK, signs the form. No information about how the process has run is recorded. This single end-of time point control limits the possibility of audits if problems are detected in later steps.

To address this issue, Advanced Biomagnetic Separation systems have recently incorporated monitoring systems to record the suspension transparency changes. By recording the transmitted light across the vessel, we can monitor the transparency changes during the whole separation process. The resultant curves give a quantitativevalue of the transparency at the end of the process, and also show how it changes since the vessel is introduced in the magnetic separation rack. Properly recorded, these graphs would allow comparing the successive batches, and generating references curves.

An antigen presenting nanoplatform for expanding T cell populations

Immunotherapy requires the manufacture and expansion of an activated T cell population. Adoptive cell transfer therapy is a promising method, utilizing a patient’s own cells and expanding them in vitro before re-introduction. Activation of T cells requires antigen presenting cells such as dendritic cells, which are capable of interacting with and stimulating the T cells. Obtaining these cells can be costly and time-consuming. As such, researchers at Yale University have come up with a way to present antigen fragments to T cells using a combination of carbon nanotubes and magnetic nanoparticles.

Mistake #5 in CLIA IVD-kit manufacturing: Inappropriate safety precautions when working with magnetic fields

The first four mistakes we described in the last weeks are related to the production process of CLIA IVD-kits. However, even if you get a perfect reproducible, high performant process, it is a last mistake you should avoid. We have frequently see IVD-manufacturers to adopt solutions implying high safety risk for the operators and the equipment.

FREE Download: Five critical mistakes in CLIA IVD-kits manufacturing

Magnetic nanoparticles used to study hearing loss

Researchers have developed a way to utilize magnetic nanoparticles to study and potentially treat hearing loss. Unlike traditional methods employing glass pipettes or similar probes, the nanoparticles developed as part of the most recent study do not impose a mechanical load on cells. Additionally, the particles greatly enhance temporal and mechanical resolution, and address a number of issues associated with studying mechanotransduction in a biological system.

Mistake #4 in CLIA IVD-kit manufacturing: Neglecting process scalability

When developing a CLIA IVD-kit, the initial focus is on the biomarker and how to coat the magnetic beads. Biomagnetic separation conditions usually get swept to one side.

The ongoing proliferation of nanotechnology research

Nanotechnology is an emerging field that has grown significantly in the recent past. The last decade has seen a proliferation of research in the nanoscience arena. According to a SciFinder search carried out in 2014 by magneticmicrosphere.com, the number of articles dealing with nanoparticles nearly doubled in 1999, then doubled again eight years later. In China, the number of articles relating to nanoscience and nanotechnology in 2010 exceeded those relating to broader subjects such as materials science, engineering, and physics [1]. This is indicative of the increased funding being directed toward projects related to nanoparticles and/or microspheres.

Mistake #3 in CLIA IVD kit manufacturing: Defining the process based purely on the separation time

Not all mistakes made in CLIA-IVD kit manufacturing involve the magnetic rack itself. Besides the two mistakes we reviewed during the last weeks, the third mistake we have detected involves process validation. Biomagnetic separation processes are often validated solely by specifying a separation time.

Self-assembling magnetic nanoparticles

In a recent study published in “Angewandte Chemie,” researchers report the development of iron oxide nanoparticles capable of self-assembling when placed in a tumor environment. Self-assembly into larger aggregates significantly improved magnetic resonance imaging (MRI) of cancer cells. The research, carried out by a team of scientists at the Imperial College London, has significant implications for the early detection and treatment of cancer.