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Biocompatible materials and Multi Jet Fusion

with human bone cell and tissue types, PA-12 has been used about 1.9 cm , similar to each well in a 24-wells polystyrene
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as a non-degradable biomaterial [48,49] . Several studies have plate. All cell culture chambers were manufactured using
reported the use of PA 11/12 for SLS printing . However, HP MJF 5200 3D-printer. HP proprietary fusing agent
[50]
few studies have explored the potential of developing (containing 5.2% carbon black suspended in a solution
biocompatible 3D-printed PA-12 bioreactors using MJF. of 65% water, 18.7% 2-pyrollidone, and 8.4% triethylene
As MJF-printing differs from SLS and other methods, we glycol) and detailing agent (containing mostly 85% water,
cannot assume that MJF-printed PA-12 possesses the same 3.7% 2-pyrollidone, and 11.1% triethylene glycol) [53,54] were
features or properties that make it equally biocompatible. used. HP 3D High-Reusability (HR) PA-12 powder was
Studies have shown that carbon black nanoparticle and used to print the cell reaction chamber. The printing was
triethylene glycol at high concentration are toxic to done on the “Balanced” print mode and new/reused powder
cells [51,52] . These are components of fusing and detailing mixture ratio was maintained at 20:80. After printing, the
agents used in MJF printing. Hence, it is uncertain if the print bed was allowed to cool to room temperature before
fusing and detailing agents in PA-12 after printing are the printed parts were retrieved.
similarly cytotoxic to cells. Although MJF produces good To examine the effect of the fusing and detailing agents
feature resolution, the printed surface is still rough and on the surface morphology and composition, specimens
irregular. It is unknown how such surface topography will without the detailing and fusing agents were fabricated
affect cell adhesion, morphology, and other anchorage- by melting and casting HP 3D HR PA-12 powder into a
dependent cellular processes. As cellular behavior can 24 mm length × 24 mm width × 10 mm height block
be manipulated by extracellular matrix, the affinity of using a convection oven (220°C, 2h and normal cooling).
MJF-printed PA-12 for protein biomolecules needs to be Then, a 16 mm blind hole was milled at a depth of 10 mm
assessed. Ease of functionalization of PA-12 allows cell (Figure 1B).
adhesion to be enhanced or manipulated.
Following the fabrication, the 3D-printed and casted
It is, therefore, the aim of this study to address these PA-12 cell culture chambers were cleaned with distilled
issues posed by the unique features or properties of MJF- water in an ultrasonic bath for 20 min. The cell culture
printed PA-12. We investigate the suitability of MJF-printed chambers were then soaked in 70% ethanol at 4°C for
PA-12 as a cell support for potential applications such as 5 min, washed, dried in an oven at 60°C for ~2 h, and then
bioreactors. To test that, we culture mammalian fibroblasts used for subsequent experiments.
and osteoblasts on PA-12 cell culture chambers 3D-printed
by MJF and check how cells tolerate being directly 2.2. Surface characterization of 3D-printed PA-12
cultivated in these MJF-printed cell culture chambers. In cell culture chambers
addition, the effect of material leachate on the cultured 2.2.1. Surface morphology
cells are also tested by exposing the cells to the leachate
of PA-12 printed by MJF. The effect of various surface The surface texture and morphology of the casted pure
coating and modification of MJF-printed PA-12, such as PA-12 and 3D-printed PA-12 were observed using
collagen and poly-D-lysine (PDL) coating or O plasma- Scanning Electron Microscopy (SEM). Specimens were
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treatment, are studied. In addition, the microbial growth fixed on metal stubs using double-sided carbon tape, gold
and adhesion on 3D-printed PA-12 are also examined. sputter coated (BALTEC, SCD 005 Sputter Coater, Scotia,
We find that MJF-printed PA-12 cell culture chambers are NY, USA), and scanned at an accelerating voltage of 10 keV
non-cytotoxic and support the growth of both mammalian using JEOL JSM-5500LV (Japan) (n = 3).
and bacterial cells. We also find out that 3D-printed PA-12 2.2.2. Surface roughness
has varied ability to support different cell types. This study
lays the groundwork for the potential use of MJF-printed The optical appearance of the surface and average surface
PA-12 cell culture chambers as bioreactors. roughness (R ) of the pure cast PA-12 and 3D-printed PA-12
a
were measured using confocal laser scanning microscopy
2. Materials and methods (Keyence Laser Scanning Confocal Microscope VK-X200
series). Surface roughness measurements were taken from
2.1. Fabrication, processing, and sterilization of three random locations on the specimens (n = 3).
3D-printed PA-12 cell culture chambers
The PA-12 cell culture chamber printed by MJF is shown in 2.2.3. Protein fouling
Figure 1A. The dimension of the printed PA12 cell culture The ability of the 3D-printed PA-12 to adsorb proteins was
chambers is 1.75 mm wall thickness, 16 mm inner diameter, studied by exposing the surface to bovine serum albumin
and 5 mm depth. This gives the chamber a surface area of labeled with FITC (BSA-FITC). Both untreated and O
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Volume 9 Issue 1 (2023) 16 https://doi.org/10.18063/ijb.v9i1.623