Effects of Two Melt Extrusion Based Additive Manufacturing Technologies and Common Sterilization Methods on the Properties of a Medical Grade PLGA Copolymer

Abstract

Although bioabsorbable polymers have garnered increasing attention because of their potential in tissue engineering applications, to our knowledge there are only a few bioabsorbable 3D printed medical devices on the market thus far. In this study, we assessed the processability of medical grade Poly(lactic-co-glycolic) Acid (PLGA)85:15 via two additive manufacturing technologies: Fused Filament Fabrication (FFF) and Direct Pellet Printing (DPP) to highlight the least destructive technology towards PLGA. To quantify PLGA degradation, its molecular weight (gel permeation chromatography (GPC)) as well as its thermal properties (differential scanning calorimetry (DSC)) were evaluated at each processing step, including sterilization with conventional methods (ethylene oxide, gamma, and beta irradiation). Results show that 3D printing of PLGA on a DPP printer significantly decreased the number-average molecular weight (Mn) to the greatest extent (26% Mn loss, p < 0.0001) as it applies a longer residence time and higher shear stress compared to classic FFF (19% Mn loss, p < 0.0001). Among all sterilization methods tested, ethylene oxide seems to be the most appropriate, as it leads to no significant changes in PLGA properties. After sterilization, all samples were considered to be non-toxic, as cell viability was above 70% compared to the control, indicating that this manufacturing route could be used for the development of bioabsorbable medical devices. Based on our observations, we recommend using FFF printing and ethylene oxide sterilization to produce PLGA medical devices.

Fabrication and Characterization of PCL/HA Filament as a 3D Printing Material Using Thermal Extrusion Technology for Bone Tissue Engineering

“…PCL and HA materials were dried in an AIRID Polymer dryer (3devo, Utrecht, Netherlands) for 3 h at 40 • C. The dried material was placed in the hopper of the filament-maker (3devo, Utrecht, Netherlands). The starting values were initially set as detailed in the PCL manufacturers' instructions and based on previous publications [34,35]. Four temperature gradients (T4-T1, where T4 is the first melting spot closest to the hopper, followed by T3, T2, then T1, the exit melting point), were adjusted to 10% higher than the PCL's declared melting temperature (60 • C → 66 • C) and the extruder rotational speed of the single-screw extruder was initially adjusted at 5 RPM to ensure that material can be extruded.…”

“…Filament cooling was performed with a dual-fan system (cooling fan speed at 100%) to achieve solidification. The final four melting zone temperatures (T4-T1) of each group were determined by decreasing the temperature by 1 • C in each cycle and decreasing the extrusion speed (RPM) until the diameter stabilized at 1.75 ± 0.05 mm, and were considered a functional diameter for material extrusion 3D printing [34]. The filament was then linked to a puller to collect the product (Figure 1).…”

Evaluation of a Medical Grade Thermoplastic Polyurethane for the Manufacture of an Implantable Medical Device: The Impact of FDM 3D-Printing and Gamma Sterilization

“…Long used in the automotive and aeronautic industries as a rapid prototyping technique, 3DP is now extended to other fields, including the biomedical and pharmaceutic domains. Various thermoplastic polymers were initially implemented by 3DP for the manufacturing of biomaterials such as polylactic acid (PLA), polycaprolactone (PCL), poly(lactic-co-glycolic) acid (PLGA) or poly(methyl methacrylate) (PMMA) [ 1 , 2 , 3 , 4 , 5 ]. Multiple medical specialties were impacted, from tissue engineering to orthopedic surgery, dentistry, cardiovascular and maxillofacial surgeries [ 4 , 6 , 7 , 8 , 9 ].…”

3D Bioprinted Scaffolds for Tissue Repair and Regeneration

“…There are plenty of reports on the preparation and application of various PLGA drug microspheres, among which PLGA microspheres as protein and enzyme drug carriers are the research hotspot (Chereddy et al, 2018). In addition, the reliability and thermal properties of PLGA enable it to be processed by additive manufacturing technology of melt extrusion (Gradwohl et al, 2021).…”