Case Study
"A brilliant idea on bioreactor design that seamlessly connects the traditional roller bottle principle to the novel high density cell culture."
See how TideCell solve your problems during cell culture and process development...
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No.
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Problems during cell culure and production
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How TideCell could solve this problem
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Comparative to other systems
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Upstream (Cell Culture/Production) issue
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1.
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Require to enhance cell attachment rate
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Relative static seeding protocol allow cells to drop, contact, adhere, and spread easier
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Dynamic state with agitation and suspension of microcarriers reduce cell attachment efficiency, especially in large scale. Even roller bottles got difficulties for efficient cell attachment if serum-free medium is applied or if cells are difficult to attach within short period of time.
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2.
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Require to perfuse or harvest product from culture medium continuously
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Cells are immobilizd in a fixed-bed containing porous carriers. Medium exchange is straight-forward and won’t damage or lost cells.
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Retain cells by filters, centrifugation, or other means reducing the scalability and require extra systems. Cells might be damaged during recovery process. Filter easier to get foul and make the process un-reliable.
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3.
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Require to semi-harvest product intermittently without interrupting cell culture process
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Matrix vessel and Medium mixing vessel is separated. Semi-harvest culture medium up to 80% doesn’t affect the Tidal motion during cell culture.
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Agitation has to be interrupted and allows the microcarrier bead to settle before able to do semi-harvest. Harvest time may be too long to drown the cells especially in large scale system.
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4.
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Require to adjust microcarrier to culture medium ratio without scarifying total cell mass with the same system
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Fixed-bed and Mixing tank ratio is adjustable enable to optimize the process easily.
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Density of microcarriers in stir tank bioreactor is usually not flexible. Lower carrier density reduce cell attachment rate, higher carrier density cause cell damage and low growth rate.
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5.
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Require to increase cell density to reduce space and labor loading
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Cell density could reach 1~6x107 per ml fixed bed.
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Cell density is difficult to increase due to No. 2, and 3.
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6.
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Infection occasion is crucial for high virus productivity
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Capability of carrier sampling from the matrix vessel. Each carrier is with similar surface area and total number of carriers in a matrix vessel is fixed. The total cell count is easy.
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Cell density is difficult to measure in roller bottle or packed-bed system. Microcrrier system is able to take carrier sample directly from the stir tank.
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7.
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Need to oberserve CPE to determine final point for harvest
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Capability of carrier sampling from the matrix vessel. Each carrier is with similar surface area and total number of carriers in a matrix vessel is fixed. The total cell count is easy.
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Conventional packed-bed system doesn’t have the capability to sample the carriers to observe CPE.
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8.
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Require to increase virus titer
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Medium could be completely refreshed before virus infection. Titer is highly increased due to high cell density and sufficient nutrient supply.
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Difficult to exchange culture medium completely and cause low virus titer due to nutrient limitation and No. 1, 2, 3.
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9.
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Require to solve foaming problems
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Oxygen supply through surface aeration. No foaming problem. No pure oxygen is required. No anti-foam agent is required and which usually is toxic to the cells.
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Oxygen supply by introducing air or pure oxygen bubbles into the liquid phase. Foaming is easily occurred, or anti-foam reagent which might be cytotoxic have to be added in the culture medium.
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10.
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Sensitive to shear stress during cell culture or during post-infection period
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Cells are protected by the porous carriers. Slow culture medium movement (1~2 mm/s) provides ultra-low shear stress to cells.
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High shear stress by agitation. Shear stress is getting higher in larger scale systems due to the tip speed in propeller is faster than the small one under the same rpm.
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11.
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Warm up culture medium take a long period of time. Semi-exchange culture medium exchange will cause temperature shock to the cells.
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Matrix vessel and Medium mixing vessel is separated. Semi-harvest culture medium up to 80% doesn’t affect the Tidal motion during cell culture. Fresh medium could be added into the medium mixing vessel gradually to alleviate the temperature shock without affecting the culture operation.
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Pre-warming of culture medium is required for most culture system, such as roller bottles, microcarrier stir tank system, packed-bed stir tank systems.
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12.
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Require to scale up to 1000 L with single-use design
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TideCell provide fixed bed capacity for up to 5x1012 cells to grow, which is equivalent to 1000 to 4000 L stir tank system.Perfusion system further down-scale the system.
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Single-use stir tank bioreactor got scale limitation at around 2000 l due to the strength of the plastic bags and risks of puncture and leakage.
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13.
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Prefer Single-use system
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TideCell could be complete single-use system
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Most systems are able to be single-use system now.
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14.
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Prefer Hybrid system
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TideCell could be partial single-use system, so called hybrid system
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Most systems if single-use, than is not autoclavable. Hybrid design is rare, or impossible.
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15.
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Prefer Autoclavable system
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TideCell could be complete Autoclavable system
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Most systems are not able to switch from single-use to Autoclavable under same configuration
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16.
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Require to control cell growth in order to promote productivity
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TideCell could control the nutrient supply by removing the culture medium and inhibit cell growth. Cell growth in TideCell won’t have over-growth problems due to the bridge effect in conventional microcarrier system has been eliminated in TideCell.
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All culture systems are submerge systems and could not control nurient supply but only by reducing feeding rate.
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17.
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Require to increase virus infection rate or transfection efficiency
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TideCell concentrate cells in the matrix vessel reducing total working volume to 1/5~1/25. It enables a concentrated virus or DNA to enhance infection or transfection efficiency.
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All infection or transfection materials are diluted into the system. Efficienct can not be promoted.
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18.
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Linear scale-up to reduce process development time
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BelloCell with 500 ml working volume and TideCell-020 with 500 L working volume reaches similar virus output (Log TCID50: 9.2 in BelloCell, 9.0 in TideCell -020)
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Roller bottle: Yes, directly increase bottle number for scale up.
Microcarrier stir tank:No. process development is time consuming.
Fixed bed bioreactor:No. Not able to scale up.
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Downstream Issue
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1.
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High impurities with host cell protein and DNA/RNA
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Cells, even lysis after virus infection, will be trapped inside the matrixes without flushing into the harvest medium. The host cell protein and DNA/RNA nucleic acid residues is several folds lower than conventional system.
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Cells will be detached and milled by the microcarrier beads during agitation after infection and release high host cell protein and nucleic acids which will be required to be removed especially the cell line is tumergenic cells.
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2.
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Require to harvest product from cells
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TideCell concentrate cells in the matrix vessel reducing total working volume to 1/5~1/25. It makes the cell harvest and down-stream recovery process easy to operate. Space, labor and operation cost is reduced dramatically.
Matrix vessel could be separated from mixing tank and placed in a freezer for direct freeze and thaw process, which make the cell harvest easier and efficient.
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In microcarrier stir tank system, cells are in the entire cell culture system and require large space and labor to harvest the cells. Cells will mix with microcarriers which require filter to separate the cells from the microcarriers, causing high lost of cells and require more washing step which increase the total volume and increse the difficulties and cost of the recovery process. Of course the recovery rate will be lower due to complex process and higher working volume.
In roller bottles, individual cell harvest is required and it is labor intensive.
In packed-bed system, it is difficult or not possible to harvest cells from the system due to the system is heavy and not being able to do tapping during cell harvest which will make the harvest of cells difficult. Freeze&thaw process is impossible.
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