CelCradle^® Benchtop bioreactor

This disposable bioreactor only works for adherent culture. However, if the said suspension cells are loosely adherent and could attach in the macrocarriers, the secreted protein can be harvested for long periods with much lower cost than commercial suspension culture system.

There are several steps to detach cells from the carriers. One is through the use of a dissociation enzyme, either trypsin, collagenase, or more. The type of enzyme to be used for a certain process depends on the type of adherent cell being cultured. Secondly, mechanical agitation is required after enzyme treatment. This is to dislodge cells from the carriers to achieve more than 90% cell harvesting efficiency.

Two pieces of carriers are required for every cell counting procedure. However, it is suggested to perform the test thrice and then stain with CVD and multiply the averaged calculated cell number by 865 (amount of carriers/CelCradle bottle). The result would be the total cell numbers. Before trypsinization, check the reference number to make sure that cells can be detached and achieved more than 90% harvesting efficiency.

Mechanical agitation through rotation or shaking the bottle is required. Alternatively, the clients can also use the automated harvesting system.

The CelCradle 500A and CelCradle 500AP disposable bottles are suitable for production of both secreted and non-secreted products. These two singe use bottles were designed to enhance the cell attachment efficiency (for loosely adherent cells) using the reverse seeding method.

Using a strainer, secreted product expelled from the medium can be harvested continuously and purified further to become the final product.

The CelCradle bioreactor is mostly used in bench-scale suitable in research and development laboratories whereas TideXcell-002 can be applied in both academia and small pilot tests. The final cell densities in both systems are related proportionally. However, the productivity and cell growth rate depend on several factors.

Since CelCradle system does not have automated pH control and perfusion process mode, the cell culture takes slower pace than TideXcell-002. With linearity of scale-up, TideXcell-002 is better than CelCradle. The parameter setting in bench scale can be used for the pilot scale, but some modifications are still necessary. Compared with other commercially available system, however, very few parameters are required to input in the TideXcell system; thus, optimization is quite straightforward.

Culture medium replenishment is important as cells consume nutrients from it. It is rather difficult to maintain 10 day-VERO culture in the system without exchanging the culture medium. However, the culture temperature can be reduced below 10°C to achieve high cell density. Addition of supplements such as glucose and glutamine concentrate can also be done to maintain cell viability.

Be sure to control pH within optimized range (usually 7.0-7.4) through addition of NaHCO3. However, the osmolarity will increase and affect the cell viability if too much sodium bicarbonate is added.

Cell culture growth curve is very important to know and check the cell’s confluency. It is recommended to perform cell growth test and to monitor cell growth daily before it reaches its plateau phase. The maximum cell density will vary depending on the cell line.

The virus infection depends on how the viruses infects cells. If the viruses could effectively infect the cells, infection procedure can be done the same way in cell seeding.

For cell harvest, inverted method for enzyme incubation is best to use as it will only require less enzyme to detach cells, less buffer media, and has higher cell recovery rate.

There are two methods for users to observe the cell culture performance.

1. Way 1: to measure the metabolite consumption in the cultured media. The pH and glucose are the basic parameters to be monitored during culture.
2. Way 2: to take out carriers from the bottle and count the cells using a stain.