Engineering Steel Baskets for Holding Cell Culture Bags

There are more uses for custom steel baskets than just parts washing or material handling. In some cases, steel baskets can be a critical part of the production process for certain materials.

This was the case when Marlin was contacted by a medical research company to create a specialized steel wire basket to hold their cell culture bags to a rotating mixer. The mixer would rotate the cell culture bags to blend the contents for even dispersal.

These cell cultures would be used in research for treating sickle cell anemia and other genetically-inherited disorders suffered by millions of people all over the world. So, it was important to get things right.

Previously, the research company had simply attached the bags directly to the rotating mixer. However, the bags would become loose and the mixing process wouldn’t be successfully completed.

The Demands of the Task

The medical mixer used by the client was a lightweight, precision instrument. The distribution of weight in the machine needed to be carefully considered, and the rotating mechanism could not be exposed to too much strain.

Additionally, the cell culture bags were made of a semipermeable plastic that was water-tight, but not air-tight. As a consequence, the bags were very delicate, and any sharp surfaces posed a severe puncture risk.

Finally, because the baskets would be used in sanitary laboratory conditions, they had to be easy to clean and sterilize after use.

Crafting the Perfect Cell Culture Mixing Basket

After reviewing the design of the mixing device used by the client, the nature of the cell culture bags, and the needs of the client, Marlin’s engineers began working on the design of the mixing basket.

The major goals of the design were:

• keeping the basket lightweight yet sturdy;
• holding the flexible cell culture bags securely without impeding accessibility;
• ensuring there were no sharps or burrs that could puncture delicate bags; and
• providing a sanitary container that was easy to clean.

To meet these goals, Marlin’s engineers started with grade 304 stainless steel as the base component for the frame and wire mesh of the basket. This material not only ensured a lightweight, sturdy basket, the protective oxide layer and smooth outer surface help prevent contaminants from settling on the basket and made it exceptionally easy to clean and sanitize after use.

To hold the cell culture bags in place in the basket, the base of the basket was lined with a woven mesh of steel wire, and two rounded wire legs were placed at either end of the basket. These “legs” had n-shaped bends near the sides that raised the wires from the surface of the basket to allow a lab technician to fit their fingers under the wire. The rest of the wire was placed just low enough to hold the bags in place throughout the mixing process.

The rounded edges of the wires would put just enough pressure on the cell culture bags to hold them in place securely without risking damage from a sharp edge or corner. Side-to-side motion was prevented by using a sheet metal border around the sides of the basket—the cell culture bags wouldn’t go anywhere once they were in the basket.

Eliminating Sharps and Burrs

One of the toughest challenges was making sure that there were no burrs or sharps that could puncture the basket. To avoid this required both a smart design and diligence in the actual assembly and finishing of the baskets.

Here, Marlin’s bevy of advanced manufacturing tools was critical. Marlin’s MFDC electric welding machines helped to prevent sharps and burrs caused by more traditional, less efficient welding processes. To eliminate any remaining burrs or sharps, each basket was passed through a wet belt sander that would grind down the steel to a smooth, shiny finish.

The end result was a small, compact basket that could safely hold cell culture bags through the client’s mixing process and ensure their success in mixing cell cultures for testing different treatments.

Need a custom wire form to make your own production process more efficient? Learn how you can get the perfect wire form for your needs today!