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International Journal of Bioprinting Sr-doped printed scaffolds for bone repair

can better regulate the concentration of Sr² released Chemical Reagent Factory (China). Dodecyl amine
+
from the scaffold, helping to modulate the immune (DDA) was purchased from Shanghai Aladdin Reagents
microenvironment and promote bone regeneration. Co. (China). Deionized water was purchased from Merck
Millipore (Germany). PCL (molecular weight: 54,000)
Briefly, we used PCL scaffolds as the basis for
constructing PDA/SrBG/PCL composite scaffolds was purchased from Jinan Dai Gang Biotechnology Co.
(China). Vitamin C and sodium β-glycerophosphate
(Figure 1). These were prepared by loading SrBG, followed were purchased from Shanghai McLean Biochemical
by surface modification with PDA. The study systematically Technology Co., Ltd. (China). Dexamethasone was
evaluated the physical properties, biocompatibility, purchased from J&K Scientific (China). Hipure RNA kit,
osteogenic differentiation, and immunomodulation of HiFiScript cDNA synthesis kit, and Ultra SYBR mixture
PCL, SrBG/PCL, and PDA/SrBG/PCL scaffolds to optimize (low ROX) were purchased from CWBIO (China).
new bone defect repair materials.
Alkaline phosphatase (ALP) kit, BCA protein assay kit, and
2. Materials and methods RIPA lysate were provided by Bi Yun Tian Biotechnology
(China). Dulbecco’s modified Eagle’s medium (DMEM),
2.1. Materials fetal serum, penicillin-streptomycin solution, phosphate
Ethyl orthosilicate (TEOS), cyclohexane, triethyl buffer, trypsin, and CCK-8 kit were provided by ATCC
phosphate (TEP), calcium nitrate tetrahydrate (CN), (United States of America [USA]). Rat bone marrow MSCs
strontium nitrate, sodium hydroxide, anhydrous ethanol, (BMSCs) and MPs (RAW264.7) were provided by ATCC
and methylene chloride were purchased from Guangzhou (USA). PDA was purchased from Tangshan Wei Hao Co.,

Figure 1. Schematic diagram of the development and systematic assessment of various PCL scaffolds. Abbreviations: ALP, alkaline phosphatase; ARG,
arginase; BMP-2, bone morphogenetic protein-2; BMSCs, bone marrow mesenchymal stem cells; CD163, hemoglobin scavenger receptor; CD206, cluster
of differentiation 206 (mannose receptor); COL1, Type I collagen; IF, immunofluorescence; IL, interleukin; INOS, inducible nitric oxide synthase; mCT,
micro-CT; Runx2, Runt-related transcription factor 2; TNF-a, tumor necrosis factor-α; PCL, polycaprolactone; PDA, polydopamine; SrBG, strontium
substituted bioactive glasses; VEGF, vascular endothelial growth factor.

Volume 11 Issue 4 (2025) 352 doi: 10.36922/IJB025210211