Cell Separation is the first step in recovering the protein product (cells) from the culture. The timing for termination of the Cell Culture is crucial and predetermined based on the quality and quantity of the product accumulated in the bioreactors. The first step in mammalian separation is usually centrifugation: a technique used for the separation of cells from culture through rapid spinning and sedimentation. The technique of centrifugation is based on the principle of density difference between particles to be separated and the medium. Centrifugation is mostly used for separating solid particles from the liquid phase (fluid/particle separation).
Microbial harvest is like mammalian however a lysing step must occur before centrifugation to free the protein contained within the bacteria.
The next step is a filtration one to remove the large debris through depth filtration. Before centrifugation and depth filtration steps, the product is cloudy. These two steps increase the transparency of the mixture and are therefore often known as Clarification steps. At this point, cells and large debris have been separated from the mixture. Depth filtration uses single-use plastic pods that have no reusable wetted parts. These depth filter pods are held in a vice-like holder because the plastic housings themselves do not have the required pressure capacity. Depth filtration is an adequate alternative to centrifugation.
Sterile grade membrane filtration is often the next step during harvest to remove smaller particles and microbial contamination. Sterile grade filtration is usually rated as 0.22µm or smaller and leaves the product translucent in appearance and ready for downstream bioprocess steps.
Single Use Assemblies
- Product transfer assemblies to transfer media, cells etc
- Centrifugal tube assemblies for harvesting
- Platinum cured silicone tubing.
- Pump-grade tubing has been developed for peristaltic pumps. It can withstand many hours of pump duration.
- Biopharmaceutical TPE tubing; suitable for welding and sealing.
- Sampling bottle system available from 60mL bottles to take a sterile sample of the product to check the quality.
- Sampling bag system from 50mL bags to take sterile samples of the product to check the quality.
- Prefilters (as built-in or separate) are available to remove products from the solution.
- Sterilizing grade filters have been specifically designed for the effective and economical processing of difficult-to-filter solutions.
- Filters for microfiltration to harvest cells.
- Dept filters to harvest cells.
- Venting filters.
- Single-use/multi-use pumps with low shear forces and high cell viability are very useful in cell harvest applications.
Plastic fittings & Connectors
- Sterile connectors can be used as an alternative to tube welding and sealing.
- Bioprocess Couplers/fittings (Y pieces, Tee’s, reducers etc) are available to connect tubing to tubing.
- Single-use sensors to monitor the pressure, flow, conductivity, pH, Temperature, and turbidity to measure the harvesting conditions
- Welders to connect TPE tubing by welding
- Sealers to seal TPE tubing by sealing