Page 216 - IJB-10-3

International Journal of Bioprinting Sr on GO enhances PLLA/PGA scaffold

means of immunofluorescence staining. 80,81 The staining of the LG scaffold were improved by adding GPSr. Our
results are shown in Figure 7, in which the ALP was results showed that the LG/GPSr1.5 scaffold had better
stained dark blue while OCN and OPN were red and green, mechanical properties, evidenced by the tensile strength
respectively. BMSCs in the LG/GPSr1.5 group showed and compressive strength of 9.49 and 19.22 MPa,
obvious dark blue changes after ALP staining, indicating respectively, which were 67.08% and 95.33% higher than
a higher activity of ALP in this group than that in the LG those of the LG scaffold. GPSr enhances the mechanical
group. Through quantitative analysis, it was found that the properties of the scaffold through crack branching, crack
expression of ALP in the LG/GPSr1.5 group increased to deflection, crack pinning, crack bridging, and pulling
0.56 μM/mg protein, which was in sharp contrast to the LG out. In addition, the LG/GPSr1.5 scaffold could induce
group. The fluorescence intensities of OCN and OPN in osteogenic differentiation of BMSCs.
the LG/GPSr1.5 group were 27.68 and 25.83, respectively,
which were significantly higher than those in the LG group. Acknowledgments
These results suggested that the LG/GPSr1.5 scaffold was The authors would like to thank Shiyanjia Lab
superior to the LG scaffold in inducing osteogenesis owing (www.shiyanjia.com) for the SEM test.
to the presence of Sr in the LG/GPSr1.5 scaffold, which
is gradually released when the scaffold degrades. Both Sr Funding
and Ca are elements of the same group, thus sharing very
similar physical and chemical properties. Sr can bind This work was supported by the following funds: (1)
to calcium-sensitive receptors on the cell membrane of The Natural Science Foundation of China (52275393,
osteoblasts and initiate intracellular signal transduction 51935014, 82072084); (2) Hunan Provincial Natural
pathways to promote osteogenesis. In addition, it has been Science Foundation of China (2021JJ20061, 2020JJ3047,
82
found that Sr may regulate the expression of osteoblast- 2019JJ50588); (3) Jiangxi Provincial Natural Science
related genes, such as OCN and ALP, which can promote Foundation of China (20224ACB204013); (4) The Project
osteoblast proliferation and differentiation and promote of State Key Laboratory of Precision Manufacturing for
bone formation. 83-85 Extreme Service Performance; (5) Technology Innovation
Platform Project of Shenzhen Institute of Information
Previous reports have demonstrated that Sr could Technology 2020 (PT2020E002); (6) Guangdong Province
promote bone regeneration by inhibiting osteoclast Precision Manufacturing and Intelligent production
differentiation and promoting bone substance education Integration Innovation Platform (2022CJPT019).
absorption. 86-89 For example, Sun et al. revealed the
inhibitory effect of strontium on osteoclast differentiation, Conflict of interest
as evidenced by the reduction in levels of key biomarkers
associated with receptor activators of nuclear factor kappa-B The authors declare no conflicts of interest.
ligand (RANKL). In fact, the concentration of released Sr
86
ions must be considered when evaluating the reparative Author contributions
potential of Sr. However, to the best of our knowledge, Conceptualization: Pei Feng
there are no referable universal concentration ranges for Sr Data curation: Feng Yang, Yun Lin
concentrations that have a positive effect on osteogenesis, Methodology: Feng Yang, Yun Lin, Saipu Shen, Cijun Shuai
and thus, more extensive and in-depth studies are required. Supervision: Cijun Shuai
In addition, it is essential to take into account the impact Validation: Saipu Shen, Yulong Gu
of both GPSr content and scaffold design on the release of Writing – original draft: Feng Yang, Saipu Shen, Yun Lin
Sr in future work, as the interplay of these parameters may Writing – review & editing: Pei Feng
affect the mechanical strength of scaffold, 90-92 and this will
become an important strategy to balance the mechanical Ethics approval and consent to participate
and bioactive properties of scaffold for future work.
Not applicable.
4. Conclusion Consent for publication
In this study, GO was encapsulated by PDA formed by
self-polymerization of DA in alkaline solution, and Sr Not applicable.
was loaded onto GO by the chelation of PDA. Then, Availability of data
the obtained GP and GPSr were added into LG, and the
scaffold was fabricated by SLS. The mechanical properties All data are available in the main text.

Volume 10 Issue 3 (2024) 208 doi: 10.36922/ijb.1829