Charged filaments: study of PLGA-HA

Charged filaments

Loading polymers with additives (such as PLGA with HA) makes it possible to adapt and improve the properties of materials to meet specific requirements.

Industrial applications include :

• Improving mechanical properties (addition of fibres or metal particles)
• Modification of thermal and electrical conductivity (addition of metal powders or carbon particles)
• Modification of aesthetic or optical properties (modification of colour or transparency with pigments)

Medical applications include :

• Functionalisation of materials to improve compatibility with the human body (e.g. addition of hydroxyapatite or β-TCP for bone implants)
• Customisation of degradation properties (e.g. mixing polymers or adding hydrophilic agents)

What is a charged filament?

A charged filament is a polymer filament intended for use in FDM (Fused Deposition Molding) 3D printing that contains additives or fillers. The aim is to improve/modify the specific characteristics of the polymer.

To do this, the polymer is mixed with the desired additive during the extrusion stage. A good quality filled filament is one with a controlled diameter (stable over the length of the spool) and with good distribution of the additive within the polymer.

What is the PLGA?

PLGA or poly(lactic-co-glycolic acid) is a copolymer composed of lactic acid and glycolic acid. Lattice Services offers PLGA-HA, a medical grade of PLGA with 85% lactic acid and 15% glycolic acid. This biocompatible thermoplastic is amorphous, transparent and has a light golden sheen. It resorbs between 12 and 24 months once implanted.

At Lattice Services, we are able to create it using custom extrusion. We can also fill other materials with other minerals.

PLGA-HA (PLGA filled with hydroxyapatite)

PLGA (Poly(lactide-co-glycolide)) filled with hydroxyapatite (HA) is widely studied and used in the medical field, particularly for bone implants and tissue regeneration. This combination of PLGA (a biodegradable polymer) and hydroxyapatite (the main component of bone) is designed to improve biocompatibility and bioactivity and promote osseointegration.

With such a filament, it will be possible to 3D print parts such as :

• Bone substitutes
• Scaffolds
• Dental implants

Advantages and disadvantages

If we compare PLGA loaded with HA to a simple PLGA filament.

The main difference is that the addition of HA will promote osseointegration, making it more suitable for bone-related applications.

However, it should be noted that the presence of HA in powder form makes the filament slightly more brittle. In addition, it is advisable to use nozzles with a minimum diameter of 0.4 mm to avoid any clogging that could be created by powder agglomerates in the filament. As a result, it is slightly more complex to print than simple PLGA.