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Thermoplastic Printheads and Thermoplastics

Thermoplastic Printheads and Thermoplastics

Integration of resorbable materials with biopriniting

Resorbable thermoplastics were one of the first type of materials that were developed for medical applications. This class of materials has found use in many applications such as surgical anchors, screws, and pins, and implants such as meshes for hernias or implantable therapies that release drugs and other factors for long term therapy or in acute cases such as suturing. The status of these materials by the regulatory authorities and their previous track record has made them an attractive component within 3D printed and 3D bioprinted constructs.

With this in mind, we have developed the thermoplastic printhead to be the easiest to use on the market with the widest range of the materials. Gone are the days where you need a filament to 3D print thermoplastics. Simply add your powder into the cartridge and extrude using the BIO X system.

The thermoplastic printhead can be utilized in conjugation with any other BIO X printhead. You can easily bioprint constructs that consist of both a thermoplastic component and a cellularized hydrogel component in the same print, all under the protection of the clean chamber technology of the BIO X.

While many materials are compatible with the thermoplastic print heads, several of the most common materials will be covered below.

Technical Specifications of the Thermoplastic Printhead:
Heating: Room temperature to 250 °C
Volume: 10 mL
Max Pressure: 700 kPa
Nozzle Range: 0.2-0.6 mm, M6 threading
Sterilization: Autoclave, ethylene oxide

Aim

To investigate the optimal printing parameters of the thermoplastics PCL, PLA and PLGA.

PCL

Polycaprolactone (PCL) is a biodegradable polyester that has found wide application in the medical field. PCL is hydrophobic and semicrystalline in nature, with decreasing crystallinity as the molecular weight of the polymer increases. Furthermore, the material exhibits a low melting point of around 60 °C. Additionally, the polymer can be mixed with other thermoplastics to generate blended materials. During the synthesis of PCL, different groups can be incorporated during co-polymerization. For example, this allows for modulation and acceleration of the degradation kinetics from 2-4 years (molecular weight dependent) in the pure PCL polymer to more rapid through the incorporation of lactones, or lactic or glycolic acids groups. Regardless, this thermoplastic has great flexibility in both drug delivery and as a scaffolding material for bioprinted constructs.

Printing temperature: 180 °C

Compatible Nozzles: 0.2 to 0.6 mm

Application Note

PCLcrop_white

PLA

PLA

Poly lactic acid (PLA) based thermoplastics are commonly utilized in the biomaterial field as it is approved by the FDA due to its degradability, processability, and biocompatibility. PLA is completely degraded by the body by hydrolysis of the ester linkages in the backbone into lactic acid and is rapidly cleared by the body. PLA has found common use in implants such as anchors, screws, pins, plates, and meshes during surgical procedures. Furthermore, the biomaterial can be utilized as a drug delivery device as its degradation can be tailored through modulation of the molecular weight, blending with other materials, and processing into constructs with high surface area done through 3D printing. The PLA base material can be found in two enantiomeric forms both a crystalline structure (Poly L-lactic acid) and an amorphous structure (Poly D-lactic acid) due to its stereochemistry and side chain organization. In the tissue engineering field, PLA has found application as a scaffolding material for cell culture, in particular the material can be blended with materials such as nanohydroxyapatite and carbon nanotubes for specific applications or used as a support material to protect softer hydrogel-based materials within the body.

Printing Temperature: 195 °C

Compatible Nozzles: 0.2 to 0.6 mm

PLGA

One of the most well-known and predominant block co-polymers of PLA is Poly Lactic-co-Glycolic Acid (PLGA). When incorporated into a block co-polymer with PLA, the resulting degradation kinetics, hydrophobicity, crystallinity, and stiffness can be easily tailored. While may blends of PLGA are found, the 50:50 ratio of lactic acid to glycolic acid is commonly utilized due to its rapid degradation in about 2 weeks. Therefore, this class of materials has found us in both drug delivery applications and for scaffolding materials for tissue engineering applications in low mechanical stress environments.

Printing Temperature: 135 °C

Compatible Nozzles: 0.2 to 0.6 mm

PLGA

Conclusion

Utilize the thermoplastic printhead and our thermoplastics to rapidly and easily fabricate constructs containing polymer constructs. Many types of thermoplastics can be utilized with the technology and more are being added every day. Use the technology to generate load bearing constructs for bone, cartilage, muscle, and ligament. Additionally, explore how drug releasing constructs can be generated.