Development of a novel disposable filter bag for separation of biomolecules with functionalized magnetic particles

Abstract

The integration of disposable magnetic filters in combination with functionalized magnetic particles represents a fast and cost-effective alternative for enzyme purification in comparison to solid/liquid separation by means of centrifugation followed by chromatographic purification. The main advantage of the particle-based process is the solid/solid/liquid separation in one step combined with disposable equipment. Furthermore this combination provides the possibility to also process biocatalytic reactions in cell-containing media into disposable equipment with preimmobilized enzymes onto the magnetic particles. The focus of the presented study is on the design and performance of a disposable filtration unit consisting of a plastic bag with an inlet and outlet and a stainless steel filter matrix. During magnetic separation, the magnetic particles selectively retard at the filter matrix due to the magnetic force, which counteracts the drag force. It was found that the length of a lengthwise aligned filter matrix should be longer than the magnetic pole surfaces in fluid flow direction. Hereby, a filtration capacity of 5.6 g magnetic particles was measured with a loss of below 0.5%. Introducing a two-phase flow optimizes the cleaning of the bag after a magnetic filtration. The procedure offered a high cleaning efficiency. Herewith, the cleaned filter unit could be discarded with minimum losses of product and magnet particles.

Agglomeration behaviour of magnetic microparticles during separation and recycling processes in mRNA purification

“…If the magnetic particle‐based separation technique is to be carried out in a technical scale production of mRNA‐based vaccine, it is not possible by using the magnetic separators used in the laboratory scale. Magnetic separators suitable for this purpose based on the principle of high‐gradient magnetic separation (HGMS), which are operated in through‐flow (“magnetic filters”), have been and are being developed in particular by Franzreb [1, 2, 58, 59] and in own work [6–8, 57, 60]. The magnetic particle suspension to be processed — in this case oligo(dT) 25 ‐functionalized magnetic beads or mRNA‐loaded oligo(dT) 25 ‐functionalized magnetic beads — is then placed in a feed vessel, which is stirred to avoid segregation due to the gravitational field.…”

“…This technique has already been applied by various working groups in the field of biotechnology as well [1–5]. It was utilized for the separation of immobilized enzymes [6–8] and used for the isolation of target molecules [9–15]. In this process, the target molecule is specifically adsorbed on the functionalized particle surface in a reaction mixture and desorbed again from the magnetic particles (called magnetic beads) after magnetic separation has taken place.…”

Development of a 3D‐printed single‐use separation chamber for use in mRNA‐based vaccine production with magnetic microparticles

“…With high‐gradient magnetic separation (HGMS), the required process technology is available. It has already been used by various working groups in the field of biotechnology [18–31]. The magnetic separators used at HGMS, which operate in the flow‐through mode (“magnetic filters”), were and are developed in particular by Franzreb [20–22] and in own work [25, 26, 30].…”

“…It has already been used by various working groups in the field of biotechnology [18–31]. The magnetic separators used at HGMS, which operate in the flow‐through mode (“magnetic filters”), were and are developed in particular by Franzreb [20–22] and in own work [25, 26, 30]. The advantage of this technique in the production of mRNA arises from the fact that the laboratory protocols used by several users in research can be transferred 1:1 to production.…”

“…Shaikh et al. [30] already tested disposable plastic bags equipped with steel wool for HGMS. Thanks to the single‐use approach, the time‐consuming cleaning in place (CIP) and sterilization in place (SIP) between different batches to avoid cross‐contamination are eliminated in the SU‐HGMS.…”