Depth Filtration

Depth filters retain particles and impurities throughout the entire depth of the porous structure through the combination of size and intermolecular interactions. Depth filtration is usually used for clarifying fermentation solutions, removing cell debris and DNA, and pre-treating plasma products and other biological products. Depth filtration can be used either alone or in combination with centrifugation. Compared with centrifugation, depth filtration is usually more effective in removing smaller debris and cell membrane fragments. Depth filtration is also widely used to improve the performance of subsequent filtration steps, most commonly as a pre-filter before sterile filtration or virus removal filtration. Many depth filters can directly remove viruses and antibody aggregates through adsorption.

SaiClear® Depth Filters

Amerigo Scientific offers SaiClear® depth filters that are specifically designed for the demanding clarification applications in the biotechnology and pharmaceutical industries. The use of SaiClear® depth filters significantly reduces the difficulty of downstream purification processes. SaiClear® P Series and S Series depth filters with different accuracy and models are available to meet different process requirements.

Our SaiClear® depth filters have small footprints, saving space in the cleanroom. Compared with traditional depth filtration systems, SaiClear® has more flexible installation position, and is easy to operate, and convenient for process development. We also provide various specifications of deep holders, suitable for packaging filters of different specifications. Compared with similar products on the market, our holders can precisely adjust the pressure level.

Filtration Accuracy

Figure 1. Filtration accuracy of SaiClear® depth filters (S/P series filter material)

Product Features

• High contaminant capacity, due to diatomaceous earth and cellulose as membrane materials
• High impurity removal capacity through mechanical interception and electrostatic adsorption
• Multiple clarification steps combined into one device to optimize the clarification process
• Products available for process reduction and scale-up

Product Applications

• Clarification filtration of fermentation and cell culture fluids
• Filtration of plasma products
• Chemical impurity removal, and decarbonization filtration
• Removal of particles and glue from process intermediates

Product Parameters

Application Case: SaiClear® Filters for the Clarification Filtration of High-density CHO Cell Harvest Solution

The purpose of clarification is to effectively separate the cells, cell debris and other colloidal substances in the harvest solution, thereby providing an impurity-free feed solution for downstream purification. Clarification of cell harvest solution is the first step in middle and downstream purification of biopharmaceutical processes. It usually employs a combination of centrifugation, tangential flow filtration, flocculation, and depth filtration. The clarification filtration of cell harvest solution usually uses two grades of depth filters: in the first-grade clarification, a filter medium with a large pore size is used to remove cells or cell debris; in the second-grade clarification, a filter medium with a tight pore size is used to remove colloidal impurities.

In this filtration application, the initial turbidity of the recombinant protein cell harvest solution was 4,851 NTU, the cell density was 35.9×10⁶ per milliliter, the cell survival rate was more that 82%, and the solid content was 12.7%. After the first clarification using the SaiClear® P20 filter and the second clarification using SaiClear® S10 filter, the final turbidity of the filtrate was less than 10 NTU.