In recent years, a number of materials with specific properties have been developed for the medical sector. This is the case of antibacterial filaments, which generate a bactericidal effect, guaranteeing the reduction or elimination of bacteria.

What are bacteria?

Bacteria are microscopic organisms and are the most abundant organisms on the planet. They can be found in all terrestrial and aquatic habitats and, of course, in humans and animals. Harmless" bacteria are known as saprophytic flora or microbiome. Only a few types of bacteria, known as pathogens, are considered infectious agents and can cause disease.

Although the mortality rate caused by infections has decreased in recent years, in the medical environment, care must be taken with certain devices, tools or items that are exposed to potentially contaminated environments. For this reason, antibacterial materials are very useful in the medical sector, as they reduce the risk of infections or the transmission of diseases through contact.

Antibacterial filaments

There are currently several FDM 3D printing filament manufacturers specialising in the development of materials with specific properties for the medical sector.

One of the manufacturers that stands out for the development of antibacterial filaments for 3D printing is Copper 3D. This Chilean manufacturer has engineers, physiotherapists and doctors on its team who work with the aim of developing materials that can solve the skin problems that patients suffer when using prostheses.

In order to achieve this, Copper3D manufactures filaments with a base material additive containing copper nanoparticles, such as PLActive and MDflex.

Video 1: Copper3D antibacterial filaments. Source: Copper3D

Thus, Copper 3D has high quality PLA and TPU 98A based FDM 3D printer filaments, both with copper nanoparticles. These scientifically validated and highly effective filaments have the following characteristics:

• The antibacterial action provided by this type of filaments is capable of eliminating 99.9% of fungi, viruses and a large number of microorganisms.
• PLActive is certified ISO 10993-5:2009 (no cytotoxic potential), ISO 10993-10:2010 (no skin irritation and no intracutaneous reactivity) and ISO 10993-12:2012 (biological evaluation of medical equipment).
• PLActive 3D printed parts can be sterilised with UCV, ozone, Ethox or bleach; but not with dry or moist heat (autoclave) because of the softening temperature of the material (55°C).
• MDflex retains all the mechanical properties of TPU, such as toughness and flexibility, has a 450% elongation at break and good resistance to high temperatures (138°C).

Image 1: Different applications of PLACTIVE AN1 and MDFlex. Source: Copper 3D.

Copper3D has sent samples of its filaments to several microbiology laboratories where studies have been carried out to prove the effectiveness of its materials.

Medphen is another manufacturer specialising in the development and manufacture of materials for the medical sector. Its products include biocompatible filaments and antibacterial filaments. The materials developed by Medphen are widely used in pharmacology, in the medical sector, in the dental industry and in cosmetics.

In Medphen's case, its antibacterial materials are based on graphene nanotechnology and are suitable for medical applications.

Image 2: Invoice stabiliser printed with Neo TPU. Source: Mephen.

Graphene nanofibres are present, for example, in Neo ABS and Neo TPU filaments, ensuring antibacterial properties and improving the performance of the base polymers. Thanks to their properties, these materials facilitate disinfection and maintain the sterility of objects that come into contact with them.

Both Copper3D and Medphen filaments are based on some of the most widely used and easy to process polymers, such as PLA, ABS or TPU. This makes FDM 3D printing with antibacterial filaments accessible to all types of users and compatible with almost any FDM 3D printer on the market.

Antibacterial filament applications

The development of new materials such as those mentioned above offers various advantages and possibilities for the manufacture of parts for the medical environment. Some of the possible applications of these filaments include:

• Manufacture of post-operative prostheses.
• Manufacture of customised orthoses.
• Manufacture of prostheses or orthopaedic shoe insoles.
• Manufacture of anatomical models for surgical preparation and rehearsal of procedures with students.
• Manufacture of medical devices such as connectors, catheters, flexible tubes, fluid and air management.
• Manufacture of medical equipment, tools or prototypes of new utensils.
• Manufacture of dispensers, pill dispensers and medicine containers, as well as protective boxes.

Thus, FDM 3D printing with antibacterial materials is a major breakthrough for the medical sector, offering advantages such as the possible personalisation and manufacture of components tailored to the patient, the reduction of waiting times or, in the case of models for surgical preparation, the reduction of the probability of error in operations.