CellCore harbouring cell's

What’s inside CellCore

The expression ”envelopes” determines the volumes containing the cell hosting material. The envelopes may be filled with a suitable material for a specific task. In the current CellCore bioreactor the matrix is a 3-dimensional scaffolding environment based on non-woven PET fibre material. Each envelope is circular with a hollow centre being the fresh media inlet and the circumference being the used media outlet. As the media pass through the matrix and not along the matrix external surface limited gradients are not created - CellCore is operating gradient free. The scaffold/matrix discs are stacked (in parallel sets of two). CellCore technology is fully scalable from few ml until production size of 15,000 ml total envelope volume.

One of the major differences between CellCore and traditional micro and fiber carriers is the fact that the media pass through the CellCore scaffold/matrix and not along the matrix body, sheet, discs or surface. For traditional micro and fiber carriers the media pass stochastic around or along the porous bodies. Separation of the cells from the media during seeding is depending on forces and separation mechanics between the cells surface and porous body surfaces. As the open cavities, space between the traditional porous bodies range millimeters traditional separation mechanics (sieving, deposition, collision, adhesion) do not support cell separation from through passing media. Plasma discharge treatment of porous bodies is needed and facilitates attraction by charge adhesion of adherent cell lines.

For CellCore technology the media is forced controlled and evenly through the entire porous body, the matrix being a scaffolding 3D environment. And hereby the freedom to separate any desired cell (particle) size and adapt to their specific characteristics. Important features of CellCore technology is:

  • Adjustable positive liquid flow during operation
  • Selectable matrix pore size and porosity
  • Selectable matrix treatment

The result is:

  • Cell seeding collection efficiency selectable between 20 and 100%
  • Complete cell separation from media during seeding time of typically an hour or two
  • Complete cell integration inside the matrix during cultivation
  • Selectable cell bleeding from the matrix

Mammalian cells range generally between 10-20 µm in size though with quite different surface characteristics between adherent and suspension cell lines. CellCore bioreactor platform is available in two specific variants – one for adherent cell lines and one for suspensions cell lines.

For the deeply interested

Particles are captured within the depth of a porous media as the fluid follows a tortuous flow path created by the series of interconnected void spaces formed by the micro filter structure (e.g., fibers, membrane, etc).  Each time the fluid flow around the micro structure, or though a porous opening, particles have an opportunity to deposit onto the structure primarily by the capture mechanisms shown in the above illustration. 

As the fluid flows around the structural elements, particles can be primarily removed from the fluid stream via the particle collection mechanisms of diffusion, interception, inertial impaction and electrostatic deposition.  Lesser importance mechanisms include sieving and gravitational sedimentation.  The particle capturing effectiveness of each mechanism is primarily dependent on the particle size, fluid velocity and size of the filter structure (e.g., fiber diameter).

Particle deposition via diffusion results when particles collide with the filter structure due to their random Brownian motion.  This random motion (zigzag path) occurs when small particles collide with fluid molecules, thereby altering the particle trajectory around the filter structure.  This motion, and hence the degree of particle capture, becomes more pronounced as the particle diameter becomes smaller, especially for particles less than 0.1 mm

A particle is deposited via the interception mechanism if a particle of finite size is brought within one particle radius of the filter structure as it follows the flow streamlines around the filter structure.  Collection via this mechanism increases with increasing particle size.  Interception becomes the dominant capture mechanism for particles in the 0.1 to 1 mm and larger size range.

Inertial impaction
Larger particles collide with the filter structure due to the mechanism of inertial impaction, as the particles are unable to follow the curve path of the gas streamline around the filter structure.  Particles deviate from their initial fluid streamline, due to their inertia (finite mass), as the fluid curves to flow around the filter structure.  This mechanism becomes an increasingly significant means of particle collection for larger particles (particle mass), and higher fluid velocities.  This mechanism becomes important for particles larger than 0.3 to 1.0 mm, depending on the fluid velocity and filter structure size.

Electrostatic effects
Particles deposit via electrostatic deposition if electrical charges on either the particle or the filter, or both, create attractive electrostatic forces of sufficient magnitude to attract the particle to the filter surface. 

Gravitational Sedimentation
Large particles (i.e., larger than 10 mm), at relatively low velocities, can be captured via gravitational sedimentation if sedimentation causes the particle to deviate from its original path and come into contact with the filter structure.

Particles unable to pass through openings in the filter structure, due to their larger size, are captured via the mechanism of sieving.  While this mechanism is operable in gas filtration, particles capable of being captured via sieving usually are captured via interception or inertial impaction before they can be captured via sieving.