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3D-Printed Anti-Tumor Scaffolds
such as hydrogels, polymer micelles, and stimulus- on tumor tissues and the toxicity to normal tissues and
responsive materials [10-12] . Three-dimensional (3D) organs.
printing technology, known as additive manufacturing
(AM), has great potential in fabricating the personalized 2. Materials and methods
scaffolds [13-15] . Based on the patient’s computed 2.1. Materials
tomography (CT) or magnetic resonance imaging (MRI),
3D models can be quickly and accurately established, PLA (MW: 500 kDa) was purchased from Sigma-Aldrich
making it possible to accurately print irregular models [16,17] . (Darmstadt, Germany), and MTX was purchased from Bio
Moreover, the drug-loaded scaffolds made by 3D printing Basic Inc. (Markham, Ontario, Canada). Cell counting kit-
technology have unique advantages in personalization, 8 (CCK-8) was purchased from Dojindo (Japan). LIVE/
spatial structure, drug components diversity, drug loading DEAD® Viability/Cytotoxicity Kit (Live/Dead) was
accuracy, and drug release sustainability [18-22] . purchased from Thermo Fisher Scientific (L-3224). The
Among various 3D printing technologies, fused fetal bovine serum (FBS), Dulbecco’s Modified Eagle
deposition modeling (FDM), which was launched by Medium (DMEM), RPMI-1640, penicillin-streptomycin,
Stratasys in 1992, has become one of the most popular and trypsin-ethylenediaminetetraacetic acid (EDTA)
technologies . The technical advantages of FDM were purchased from Grand Island (New York, USA). All
[23]
include the selectivity of a variety of applicable materials, the reagents were used without further treatment.
customized high precision, and low cost . As a typical
[18]
heat dissipation technology for scaffolding, FDM uses a 2.2. Preparation of the PLA and PLA/MTX
thermoplastic polymer filament, which is heated to the composite filaments
melting point, and then extruded from the nozzle, and The mixture of PLA and MTX was melted and extruded
deposited layer by layer to create a scaffold [20,24-27] . The using granulators. PLA/MTX and PLA filament were
thermoplastic materials used in FDM technology include prepared by the 3D printing consumable extruder (SHSJ,
polylactic acid (PLA), poly(ε-caprolactone) (PCL), poly Songhu Machinery Co., Ltd., Dongguan, China) with a
(methyl methacrylate) (PMMA), polycarbonate (PC), 1.75 ± 0.05 mm constant diameter at 220°C and cooled
and acrylonitrile butadiene styrene (ABS) [28-35] . Among by water, and the screw speed was 45 rpm.
these thermoplastic materials, PLA has been approved
by the FDA as biomedical material due to its excellent 2.3. Fabrication of PLA/MTX scaffolds
biocompatibility [36,37] . Studies demonstrated that 3D
printing is a powerful tool for manufacturing personalized The 3D printing bracket was designed using Mimics
scaffolds with specific geometries. Fouladian et al. software and SolidWorks2015 software. STL files were
reported that 3D-printed stents loaded with 5-fluorouracil converted to a format (gcode) recognizable by 3D
(5-FU) drug were used to treat esophageal cancer. printer (ShanRui DK2, Guangzhou, China) using CURA
Incorporating anti-cancer drugs into endoluminal stents software. An ink cartridge was added to the 3D printer
can provide a sustained release of drugs to esophageal to transport the PLA/MTX composite filaments, and the
malignant tissues while prolonging the retention of the filaments were drawn and melted (210°C) and extruded
stent and relieving dysphagia . through a nozzle (0.4 mm) to print layer by layer.
[38]
The purpose of this research is to prepare porous 2.4. Characterization of PLA/MTX scaffolds
PLA/MTX scaffold with a controllable MTX release.
PLA/MTX filaments with different MTX concentrations The structures and aperture sizes of PLA/MTX scaffold
(MTX mass fraction: 0.5 wt%, 1.5 wt%, and 2.5 wt%) were characterized using field emission SEM (SEM,
were prepared by melt mixing and extruding method. Zeiss_Supra55, Germany). Energy-dispersive X-ray
PLA/MTX scaffolds were printed by FDM using prepared analysis (JXA-8230, JEOL, Japan) was then used to
PLA/MTX filament. The morphology, composition, and perform elemental analysis of the PLA/MTX scaffold
structure of printed PLA/MTX scaffold were investigated surfaces to assess the distribution of MTX in the PLA
by scanning electron microscopy (SEM) and energy- matrix.
dispersive spectrometer (EDS). The biocompatibility The high-precision digital density meter (ED-1000,
of printed PLA/MTX scaffolds and the inhibitory Shanghai Tuxin Electronic Technology Co., Ltd.) was
effect on tumor cells were evaluated in vitro by mouse used to measure the porosity. The porosity calculation
embryo osteoblast precursor cells (MC3T3-E1), human formula is as follows:
osteosarcoma cells (MG-63), human breast cancer cells
(MCF-7), human lung cancer cell lines (A549), and mouse Porosity (%) = (1-(m/ρ)/V) × 100%
breast cancer cells (4T1). In addition, the subcutaneous
xenograft model was used to explore the inhibitory effect Where, V: outer volume, m: mass, and ρ: density.

136 International Journal of Bioprinting (2021)–Volume 7, Issue 4