Page 307 - IJB-10-4

International Journal of Bioprinting PCL/Fe3O4@ZIF-8 for infected bone repair

choice to mix with Fe O @ZIF-8 nanoparticles to fabricate were collected by a magnet, washed with anhydrous ethanol
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PCL/Fe O @ZIF-8 by 3D printing. and deionized water for three times to remove unreacted
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The aims of this study are to fabricate a novel precursors and impurities, and then dried overnight in a
multifunctional magnetic PCL/Fe O @ZIF-8 composite vacuum oven at 60°C. Fe O @ZIF-8 nanoparticles were
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freeze-dried for future use.
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scaffolds by 3D printing, and systematically investigate
the physicochemical properties and treatment effects 2.3. Preparation of PCL/Fe O @ZIF-8 scaffolds by
in infected bone defect. The mechanical properties, 3D printing 3 4
biocompatibility, antibacterial properties, and osteogenic In this study, a fused deposition molding (FDM)-
activity of the composite scaffolds were also investigated in based process technology was used to fabricate the bio-
detail. Finally, the antibacterial properties and osteogenic scaffolds via a homemade bio-3D printing platform
ability of the composite scaffolds in vivo were also evaluated (Xi’an Jiaotong University, China). Firstly, PCL solution
through animal experiments. was prepared by dissolving PCL particles in 1,4-dioxane.
Then, the PCL solution was mixed with Fe O @ZIF-8
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2. Materials and methods nanoparticles at concentrations of 0 wt%, 5 wt%, 10 wt%,
and 15 wt% and stirred vigorously for 12 h to make pure
2.1. Materials PCL, PCL/5%Fe O @ZIF-8, PCL/10%Fe O @ZIF-8,
All reagents used were of analytical grade and were used and PCL/15% Fe O @ZIF-8, respectively. A disc-shaped
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without any purification. C H N (>98%), Zn(NO ) ∙6H O scaffold structure with 8 mm in diameter, 2 mm in height,
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(≥99%), methanol (99.5%), anhydrous ethanol (≥99.7%), 400 μm in wire diameter, and 800 μm in wire spacing was
FeCl ∙6H O (≥99%), (CH OH) (≥99%), polyethylene designed and 3D-printed. The mixture of PCL and Fe O @
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glycol (molecular weight 20,000), NaAc∙3H O, and ZIF-8 nanoparticles was melted in a heated glass syringe
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1,4-dioxane were purchased from Anhui Zesheng at 85°C, and extrusion printing was performed through a
Technology Co., Ltd. (Shanghai, China). PCL (molecular stainless-steel nozzle with 400 μm inner diameter using a
weight 80,000) was obtained from Daigang Biological microinjection pump (TJ2A; Longer Pump, China). The
Engineering Co., Ltd. (Jinan, China). Staphylococcus aureus flow rate of FDM printing was 1800 μL per hour, and the
(ATCC 25923) and Escherichia coli (ATCC 25922) were printhead movement speed was 3 mm/s. After printing,
purchased from the American Type Culture Collection. the fabricated pure PCL and PCL/Fe O @ZIF-8 scaffolds
Dickkopf-1 (DKK1) was purchased from Merck KGaA were dried in an oven at 37°C for 2 days. 4
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Co., Ltd. (Darmstadt, Germany).
2.4. Characterization of Fe O @ZIF-8 nanoparticles
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2.2. Synthesis of Fe O @ZIF-8 nanoparticles and PCL/Fe O @ZIF-8 scaffolds
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Fe O nanoparticles were prepared by solvothermal The morphology of Fe O @ZIF-8 nanoparticles was
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synthesis as previously published literatures. In brief, observed via transmission electron microscopy (TEM;
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5.00 mmol of FeCl ⋅6H O, 0.05 mmol of polyethylene HT7700, Hitachi, Japan). The functional groups and
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glycol, and 26.47 mmol of sodium acetate trihydrate were composition in the nanoparticles were analyzed by using
dissolved in 40 mL of ethylene glycol, and the solution Fourier transform infrared spectrometer (FTIR; Nicolet
was stirred until clear. Thereafter, the mixed solution was iS10, Thermo Fisher Scientific, USA) and powder X-ray
transferred and reacted in a lined Teflon reactor at 200°C diffractometer (XRD; SmartLab3, Rigaku, Japan). The
for 72 h. After the solution was cooled to 25°C, the black thermal stability of the nanoparticles was measured under
precipitate was collected by magnetic separation, washed nitrogen atmosphere with flow rate of 50 mL/min and ramp
three times with absolute ethanol and deionized water, rate of 5°C/min from 30°C to 600°C by thermal gravimetric
and dried in a vacuum oven at 60°C for 12 h. The resultant analysis (TGA) device (Pyris 1, Perkin Elmer, USA).
black powders were Fe O nanoparticles. The surface morphology and elemental distribution of
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Fe O @ZIF-8 nanoparticles were fabricated by the the 3D-printed PCL/Fe O @ZIF-8 scaffolds were detected
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coprecipitation method. Firstly, the obtained Fe O by scanning electron microscopy (SEM; JEOL JSM-7800F,
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nanoparticles (100 mg) was added into 30 mL of methanol Japan) and energy dispersive spectra (EDS) analysis,
solution dissolved with Zn (NO ) ∙6H O (1800 mg), respectively. The mechanical strength of the scaffolds
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and the mixed solution was ultrasonicated for 15 min. was tested by an electronic universal testing machine
Next, 30 mL of methanol solution containing 3900 mg (CMT4304, Xi’an Lichuang material testing Technology
of 2-methylimidazole was added, ultrasonicated for 15 Co., Ltd., China) with a maximum force setting of 3000
min, transferred to a three-mouth bottle, and then stirred N and a rate of 1 mm/min (six replicates in each group).
vigorously at 25°C for 4 h. Finally, the composites obtained The magnetic properties of the scaffolds were measured
Volume 10 Issue 4 (2024) 299 doi: 10.36922/ijb.2271