Page 332 - IJB-10-5

International Journal of Bioprinting Immunomodulatory bone repair by MBG/PCL

(the medium removed from each group of samples was Joyner, Halenda) pore size distribution calculation model.
collected and mixed with osteogenic induction solution The pore size distribution graph of MBGs can is displayed
at a ratio of 1:5 to prepare MP-conditioned medium in Figure 1D. The mesopore size distribution of the glass
for spare use). On days 1 and 3, real-time fluorescence microspheres was between 3 nm and 54 nm, and the
quantitative polymerase chain reaction (PCR) was used specific surface area of the bioactive glass microspheres
to detect the expression of the M1 immunomarker genes was calculated to be 457.14 m /g, the pore volume was 1.38
2
Tnfa, recombinant human interleukin-1 beta (Il1b), and cm /g, and the average pore size was 11.83 nm.
3
the M2 immunomarker genes CD206 and arginase (Arg).
Glyceraldehyde phosphate dehydrogenase (Gapdh) was 3.2. Characterization and physicochemical
used as an internal reference gene. properties of MBG/PCL scaffolds
PCL scaffolds containing different concentrations of MBG
2.4.4. Evaluation of the osteogenic performance of were printed using a 3D printer. Observed by SEM, as
each group of scaffolds. shown in Figure 2A, the filament diameters of the scaffold
BMSCs (1 × 10 ) were added into 48-well plates containing group researched were of uniform thickness, and the fiber
5
scaffold samples. After 24 h of incubation, the supernatant directions differed by 90° from each other. Scattered pores
was aspirated and discarded, and complete culture medium existed on the surface of the scaffolds, and MBG particles
or osteogenic induction medium (100 mL complete were visibly attached to the surface of 5MBG/PCL, 10MBG/
culture medium + 0.39 mg dexamethasone + 1.76 mg PCL, 20MBG/PCL, and 30MBG/PCL scaffolds. Under
vitamin C + 306.11 mg sodium β-glycerophosphate) or high magnification, we found that the scaffold surface
MP-conditioned medium was added, respectively. The became rougher with the increase of MBG content, with
medium was changed periodically. After 7 and 14 days of 30MBG/PCL demonstrating the most significant result.
osteogenic induction, the induction was terminated, and These rough surfaces can provide sites for cell adhesion,
real-time fluorescence quantitative PCR was used to detect which is more conducive to guiding cell proliferation,
the osteogenic marker genes alkaline phosphatase (Alp), differentiation, and other behaviors. 32,33 As shown in
Runt-related transcription factor 2 (Runx2), osteopontin Figures 2B and 3E, the contact angles of 0MBG/PCL,
(Opn), type I collagen (Col1), and bone morphogenetic 5MBG/PCL, 10MBG/PCL, 20MBG/PCL, and 30MBG/
protein-2 (Bmp2) in the cells, and Gapdh was used as the PCL scaffolds were 108.78 ± 1.45°, 107.93 ± 1.42°, 107.35 ±
internal reference gene. ALP enzyme activity was assayed 1.65°, 99.12 ± 3.69°, and 96.15 ± 0.97°. The smaller contact
on days 7 and 14 using the BCA method. angle indicates that the material is more hydrophilic.
Overall, the addition of MBG improves the hydrophilicity
2.5. Statistical analysis of PCL materials, and the degree of improvement is related
The experiments were repeated six times, and the results are to the concentration of MBG. As shown by FTIR analysis
expressed as the mean ± standard deviation. All statistical (Figure 3A), the characteristic peaks of PCL appeared in all
analyses were processed using GraphPad Prism software. groups of scaffolds, of which -(CH ) - at 2850–3000 cm
-1
2 4
One-way analysis of variance (ANOVA) followed by was CH stretching vibration, 1750 cm was C=O stretching
-1
Dunnett’s multiple comparison test was used to determine vibration peak, and 1150–1250 cm represented -C-O-. The
-1
significant differences between the experimental groups. original characteristic peaks of PCL gradually decreased
Results with p-value less than 0.05 were considered with the increase of MBG content. By thermogravimetric
statistically significant. analysis of each group of scaffolds (Figure 3B), the mass
loss of scaffolds with low to high MBG content was 100%,
3. Results 95.896%, 91.43%, 86.005%, and 78.807% in order, and the
3.1. Characterization of MBG mass of the remaining inorganic particles in each group of
The MBG micromorphology was characterized by SEM scaffolds was the same as the proportion of the mixed MBG.
and TEM. It can be seen from Figure 1A that our prepared In the compression resistance test of the scaffolds (Figure
MBG is a microsphere formed by the stacked combination 3C), we can see that the maximum compressive strength
of many small nanoscale particles, and the glass of pure PCL scaffolds was 8.39 ± 0.47 MPa, and with the
microspheres are well dispersed with a loose and porous increase of MBG content, the PCL’s compression resistance
surface. From the transmission electron micrographs experienced a gradual increased. The compressive strength
(Figure 1B), it can be found that the pore channels of of 5MBG/PCL scaffold was 9.70 ± 0.62 MPa, and it was
the glass microspheres are dendritically distributed. The most significant at 17.81 ± 0.35 MPa for 210MBG/PCL
N adsorption–desorption curves in Figure 1C indicate scaffold. However, on this basis, the compressive strength
2
that the MBGs are mesoporous materials exhibiting type of the scaffolds gradually decreased with the increase
IV isotherms, which were adopted by the BJH (Barrett, in MBG content. 20MBG/PCL (11.21 ± 0.70 MPa) and

Volume 10 Issue 5 (2024) 324 doi: 10.36922/ijb.3551