Clean room production of breast implants

Mr. Janning, what properties must polymer structures have so that they can be implanted and gradually get absorbed by the body?

Kai Janning: To be suitable as an implant, cytocompatibility, biodegradability and thermal and mechanical properties of polymers play an important role. For its Senella® implants, BellaSeno chose polycaprolactone (PCL), a biodegradable, thermoplastic polyester whose excellent biocompatibility performance has been known for many years. The plastic is popular as a bioresorbable yarn in surgical sutures and has thus been established for a variety of clinical applications. After implantation in the body has occurred, hydrolysis is one process that gradually breaks down the ester bonds of the polymer chains. The breakdown products are subsequently fully metabolized via the citric acid cycle, which means no foreign substances stay behind in the body. The implants are designed to where the absorption rate and the mechanical properties are coordinated to facilitate a gradual resorption by the body and to maintain the required scaffold structure while the patient's tissue regenerates.

How long did the implant development take?

Janning: Our project partner BellaSeno has been working on the development of the implants for several years and is currently in the clinical trial phases. As part of the "BellaFactum" research project, over the next three years we are concurrently developing a fully automated production platform that will make the entire manufacturing process more controlled, efficient, and cost-effective once it has received market approval.

How have the implants been made until now?

Janning: So far, the implants are individually made in a clean room using a special 3D printer that is loaded, started, and monitored by well-trained staff. The 3D printing process is followed by multiple manual quality control steps before the finished product is packaged and ready for shipment. These manual processes are very time-consuming and labor intensive, making a high throughput not feasible.

 How is the new production facility better than the previous process, and what are its features?

Janning: All production processes are fully automated in the new clean room facility to where only the polymer raw materials are added to the system and finished implants can be retrieved at the end.

Exhibitors and products around machines for additive manufacturing:

• Binder jetting technology
• Fused Deposition Modelling
• Stereolithography
• Polyjet modelling
• Other machines

The system's processes thus include – among other steps – the preparation of the plastic pellets for 3D printing, 3D printer supply and calibration, in-line quality controls for additive manufacturing, gravimetric, optical, and mechanical validation, decontamination, as well as the handling and storing of the implants. This facilitates 24/7 staffless operation that only requires occasional staff inspections. This is the first scalable, fully automated, cloud-based production system for additively manufactured, custom medical implants of its kind. We at the Fraunhofer IPT are setting a new standard in this area together with our partner BellaSeno.

How are the polymer structures for the implants manufactured in the new facility?

Janning: The raw material is medical-grade PCL pellets that are liquefied and used to print scaffolds via an innovative, specially developed 3D printing system. An optical in-line quality control system continuously monitors the printing process and intervenes directly in case of printing errors.

What unique challenges come with the development of a medical device production facility?

Janning: The fundamental principle is to make certain that the fully automated production process in the facility is in no way inferior to the manual production process. You must therefore show that the individual processes in the system don’t have a negative impact on the quality of the device at any point. Of course, our claim is that our system delivers much higher quality, higher throughput and reduces waste. Conforming to the good manufacturing practice regulations (GMP) during the system’s development guarantees this. Quality assurance and regulatory requirements are of prime importance when it comes to medical devices. That is why process design must comply with the regulatory requirements as outlined in the Medical Device Reporting (MDR) and the FDA's regulation of medical devices.

How can polymers be enhanced to garner human health benefits in the future?

Janning: Undoubtedly, polymers play a major role in medicine and there is no replacement when it comes to countless applications. The many types of polymers and their combination possibilities allow researchers to create the ideal material properties for a variety of uses. Still, modern polymers will eventually also reach their limits. Despite excellent biocompatible properties, it is often impossible to avoid foreign body reactions. Yet maximum biocompatibility is crucial in implantology. Intensive research is necessary and ongoing to accommodate these needs. This includes studies in areas such as biohybrid materials, resorbable materials, and surface modification. If scientists can create new types of polymers with more advanced properties in the future, it will promote innovation in medical devices and boost essential health benefits.