Overview

• Post By : Priyabrata Pattnaik


• Source: Ami Polymer Pvt Ltd


• Date: 06 May,2026

In biopharma manufacturing, Single-Use Technology (SUT) has allowed for much greater flexibility and responsiveness. But, this comes with significant cost. Loss of integrity with any of the bags used in SUT systems is a danger.

All that is needed is a tiny pinhole in the seam, and a sensitive high-value batch of media or drug substance can become a total loss. Knowing the cause of the loss and understanding the conditions to avoid it is essential to keep the process sterile and efficient.

The Potential Problems with Sealing

The center of what can be achieved with SUT is the multilayer polymer films. The ability to it into the thermoplastics is a standard of the industry. Other options for things that are more apart of the delicate and or heat sensitive applications, Ultrasonic Bonders can create an airtight seal. Tube welding allows the connection to the C-Flex thermoplastic tubes to a closed system.

The Causes of Single-Use Bag Failure

Though SUT is a relatively new technology, bags have been failing for a long time because of what is called the Sealing Paradox. The bags are multilayered and are composed of a strong outer layer, either of Nylon or of PE, and an inner, sealing layer, which can either be EVA or LDPE.

The Narrow Sealing Window

Being precise in this instance is extremely important. If the sealer is a mere 2 degrees cooler than it should be, it results in a seal that is temporary and yields to the pressure of the replete bag. If, however, the heat is too great, it erodes away the polymer and makes it extremely brittle.

Interface Contamination:

If even a minuscule droplet of protein media splashes onto the area where the seals interact before fusion occurs, this creates a barrier which would prevent the polymers from knitting together to cause a “channel leak.”

Flex Cracking: “sloshing” of the liquid during the transport creates a repeated folding stress on the corner of the bags.

As bags are made of a single sheet of material this eventually leads to plastic insanity (bags collapsing in on themselves)

Layering Difficulties

Each layer containing seals on a five-layer laminated film presents increasing difficulty in comparison to sealing a simple plastic bag. The biggest challenge would be thermal lag, it would be imperative for the heat to seep through protective layers in order to activate the sealant in the middle of the layers.

The “T-junctions” where the side seals intersect with the port sealing layers, would be nearly impossible to achieve a uniform seal, because of the intersecting layers of film.

Also, materials such as EVA possess while “material memory” are attempting to return to their original form upon cooling, will result in internal stress, progressively worsening the seal.

Next Steps on the Topic

Quality by Design (QbD) has become the appropriate approach in the industry going forward.

Technical Innovations: Laser welding has enabled the heat to be localized to the middle of the sealant. This change has introduced a margin of safeness through the implementation of Redundant Sealing (double seals).

 Rigorous Testing: The development of Helium Integrity Testing has enabled the detection of extremely small leaks to match an even finer scale as compared to traditional pressure testing.

Process Improvements: Innovations in the design of secondary packaging and use of foam inserts has greatly reduced the “slosh factor” observed during shipping. The use of sensor-integrated containers has provided advances in leakage prevention by issuing preemptive alerts of increased levels of moisture.

EVA is still the go-to for gas permeability, but many plants prefer Polyethylene (PE) blends for large-volume storage due to their greater mechanical strength and resistance to “creep.” With advancements in material science and consistent workflow sealing, biopharma can finally close the gap on bag failures.

Written By: Priyabrata Pattnaik

Chief Executive Officer (CEO)

Mail Id: [email protected]