Page 310 - IJB-10-4

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

size defect model was used. Eighteen SD rats were also aromatic C-H stretching, aliphatic C-H stretching, and
randomly divided into control group, PCL group, and C=N stretching of imidazole ring, respectively. In the
PCL/Fe O @ZIF-8 group. The surgery procedure of Fe O curve, the peak at 576 cm was related to the typical
−1
4
3
4
3
scaffolds implantation in skull defect was the same as Fe-O vibration. As illustrated in the Fe O @ZIF-8 curve,
4
3
the above procedure. The rats were sacrificed at 6 and 12 the characteristic bands of ZIF-8 and Fe O were observed
4
3
weeks after surgery, and the tissue samples were examined in the FTIR spectrum of Fe O @ZIF-8, indicating the
3
4
by micro-CT and histological analysis. For micro-CT successful combination of ZIF-8 and Fe O . Interestingly,
4
3
examination, the whole skulls were collected, fixed with the peak belonging to Fe-O vibration was changed from
4% paraformaldehyde for 24 h, and then scanned by using 576 cm (Fe O ) to 615 cm (Fe O @ZIF-8), which may
-1
-1
3
4
4
3
a micro-CT machine (AX2000; Aoying Testing Technology be related to the link of Fe O nanoparticles to ZIF-8.
4
3
Co., Ltd., China). Then, histomorphometric analysis was Furthermore, the crystal structures of ZIF-8, Fe O , and
3
4
conducted using the auxiliary histomorphometric software Fe O @ZIF-8 were determined by XRD analysis. The XRD
3
4
(Concepts NREC, USA) to calculate the bone volume pattern of Fe O @ZIF-8 showed the characteristic peaks of
4
3
fraction (BV/TV) and number of trabeculae (Tb.N). both ZIF-8 and Fe O , suggesting the successful formation
4
3
For histological analysis, the skull was fully decalcified of Fe O @ZIF-8 from the two components (Figure 1E).
4
3
and embedded in paraffin, and then 3-µm-thick tissue 3.2. Characterization of PCL/Fe O @ZIF-8 scaffolds
slices were cut from the cross-section in the central area The scaffolds were successfully manufactured by 3D
3
4
of the defect. New bone regeneration was assessed with printing of PCL and Fe O @ZIF-8 nanoparticles doped
the aid of H&E and Masson’s trichrome staining. The with various proportions, in a regular fashion. The
3
4
expression of β-catenin and RUNX2 was also detected by surface morphology of the PCL, PCL/5%Fe O @ZIF-
immunofluorescence staining. 3 4
8, PCL/10%Fe O @ZIF-8, and PCL/15%Fe O @ZIF-8
3
4
3
4
2.12. Statistical analysis scaffolds was observed via SEM (Figure 2A). The SEM
The quantitative data in all experiments were statistically results showed that all scaffolds exhibited a square
analyzed by GraphPad Prism 9.0 software (San Diego, porous grid structure, and the square macro-pores on
USA). The data are presented as the mean ± standard the scaffolds were oriented at 0 and 90 degrees between
deviation (SD). The difference between multiple groups was adjacent layers (Figure 2A, first row). Notably, the pure
compared by using one-way analysis of variance (ANOVA). PCL scaffold presented a smooth surface, while the
Statistical significance was considered at p < 0.05. introduction of Fe O @ZIF-8 nanoparticles resulted in a
3
4
comparatively roughened surface (Figure 2A, second row).
3. Results The nanoparticles dispersed randomly on the surface of
the PCL/Fe O @ZIF-8 scaffolds during the continuous 3D
4
3
3.1. Characterization of Fe O @ZIF-8 nanoparticles printing process, with their density correlating positively
3
4
Based on the fabrication procedure shown in Figure 1A, with the content of Fe O @ZIF-8 nanoparticles (Figure 2A,
4
3
we successfully synthetized Fe O @ZIF-8 nanoparticles third row). Particularly, with an increase in Fe O @ZIF-8
4
3
4
3
through coprecipitation method. The transmission nanoparticles content, the surface roughness and porosity
electron microscopy (TEM) results showed that Fe O @ of the scaffold escalated significantly.
4
3
ZIF-8 nanoparticles presented hexagonal morphology
with diameters between 50 and 100 nm, and spherical- Moreover, EDS analysis was conducted to ascertain
shaped Fe O nanoparticles were closely attached in ZIF-8 the elemental composition of the scaffolds, and the
4
3
crystals (Figure 1B). TGA results showed that Fe O @ZIF- corresponding spectra for the four types of scaffolds
3
4
8 particles were stable below the temperature of 300°C, variations with different Fe O @ZIF-8 doping ratios were
3
4
and the sharp weight loss temperature of Fe O @ZIF-8 was recorded (Figure 2B). The characteristic peaks for Zn
4
3
around 350°C, which was slightly lower than that of ZIF-8 and Fe elements were observed on each EDS spectrum
at around 380°C (Figure 1C). Furthermore, the loading of of PCL/Fe O @ZIF-8 scaffolds, indicating the presence of
4
3
Fe O into ZIF-8 host was estimated to be 13.1%, according Fe O @ZIF-8 nanoparticles in the scaffolds. The detailed
4
3
3
4
to the weight loss calculation of ZIF-8 and Fe O @ZIF-8 element ratio data of the scaffolds are provided in Table S2
4
3
particles. Figure 1D shows the FTIR spectrum of Fe O , (Supplementary File).
4
3
ZIF-8, and Fe O @ZIF-8 nanoparticles. The characteristic The mechanical strengths of the scaffolds were also
3
4
bands of ZIF-8 and Fe O observed in this study were detected, and the compressive stress–strain curves are
3
4
similar to those reported in other published studies. 21,22 shown in Figure 2C. The compressive strength and
In detail, the ZIF-8 spectrum yielded characteristic peaks elastic modulus of the PCL/Fe O @ZIF-8 scaffolds were
4
3
at 3154, 2359, and 1615 cm , which were attributed to significantly higher compared to pure PCL scaffolds,
-1
Volume 10 Issue 4 (2024) 302 doi: 10.36922/ijb.2271