Page 156 - IJB-9-5

International Journal of Bioprinting Guide about the effects of sterilization on 3D-printed materials for medicine

Table 1. Information about the material and the 3D printing technology
Printing Material Vendor City and country of origin Sample Flexible/Elastic Institute responsible
technology for printing
SLA Elastic 50 Formlabs Massachusetts, USA Cylindrical Yes HSJD
SLA Flexible 80 Formlabs Massachusetts, USA Cylindrical Yes HSJD
SLA Durable Formlabs Massachusetts, USA Type 1A ISO 527 No HSJD
SLA Surgical Guide Formlabs Massachusetts, USA Type 1A ISO 527 No HSJD
MJ Elastic Clear Stratasys Stratasys, Minnesota, USA Cylindrical Yes HSJD
MJ MED610 Stratasys Stratasys, Minnesota, USA Type 1A ISO 527 No HSJD
MJ VERO Stratasys Stratasys, Minnesota, USA Type 1A ISO 527 No HSJD
FDM ABS Kimya Nantes, France Type 1A ISO 527 No HSJD
FDM PLA Kimya Nantes, France Type 1A ISO 527 No HSJD
FDM TPU/TPE Recreus Alicante, Spain Cylindrical Yes CIM UPC
SLS PA12 3D Systems Hemel Hempstead, UK Type 1A ISO 527 No CIM UPC
Abbreviations: ABS, acrylonitrile butadiene styrene; CIM UPC, Centre CIM of Universitat Politècnica de Catalunya; FDM, fused deposition modeling;
HSJD, Barcelona Children’s Hospital Sant Joan de Déu; MJ, material jetting; PLA, polylactic acid; SLA, stereolithography; SLS, selective laser sintering;
TPE, thermoplastic elastomer; TPU, thermoplastic polyurethane

samples were manufactured using Epsilon W50 (BCN3D, printer was used at HSJD. The samples were manufactured
Barcelona, Spain). The printing parameters were the same horizontally.
for all materials, i.e., a nozzle diameter of 0.4 mm, a layer
height of 0.1 mm, an infill of 80%, an infill overlap of 2.3. Sterilization method
15%, and a wall thickness of 0.8 mm. The samples were To evaluate the critical effect of sterilization methods
manufactured horizontally. in 3D-printed, custom-made medical devices used in
hospitals, three of the most used sterilization processes
2.2.2. Stereolithography available in clinical settings were selected following
This process is based on photopolymerization of resins clinically validated protocols. To compare the effect of the
using UV laser to create the layers. Each layer is solidified different processes, the produced specimens were divided
in x–y directions and the building platform rises in z into control and study groups. For each material, three
direction to create the different layers. For the manufacture specimens were printed for each sterilization method,
of Surgical Guide, Durable samples, Elastic 50, and Flexible and three more specimens were printed as controls. The
80 samples, a Form 3BL (Formlabs, Massachusetts, USA) sample size is considered appropriate since the objective
was used at Barcelona Children’s Hospital Sant Joan de is to demonstrate the effect of sterilization on each
Déu (HSJD). The samples were manufactured with an material, instead of demonstrating the exact mechanical
angle of 20° from the building platform to increase product property value of each material (since the mechanical
resistance and facilitate postprocessing. property values of each material are already given by the
manufacturers [Table 2] and several studies have already
2.2.3. Selective laser sintering investigated in this regard for each material). Mechanical
SLS is a process in which the 3D printer uses a laser as both the results between studies and manufacturers may vary due
power and heat source to sinter powdered material layer-by- to different testing methods used.
layer until the 3D object is manufactured. For the manufacture
of the PA12 samples, a Ricoh AM S5500P was used at CIM No sterilization or disinfection process was applied
UPC facilities, which has a layer thickness between 0.08 and to the control sample. The study group samples were
0.1 mm. The samples were manufactured horizontally. subjected to three different sterilization procedures, i.e.,
HPO, Autoclave 121, and Autoclave 134, available at a
2.2.4. Material jetting sterilization-certified facility at HSJD. All of them were
MJ is based on photopolymerization of material jetted onto performed using machines from Matachana (Italy). Those
the printing platform, where it is solidified by UV light methods are among the most used for the sterilization of
and the model is built layer-by-layer. For the manufacture medical devices. Not all material samples were subjected to
of the MED610, VERO and Elastic Clear samples, a J5 sterilization methods. The melting limit of each material,

Volume 9 Issue 5 (2023) 148 https://doi.org/10.18063/ijb.756