Stem Cell-Seeded 3D-Printed Scaffolds Combined with Self-Assembling Peptides for Bone Defect Repair

Area of Science:

• Biomaterials Science
• Regenerative Medicine
• Tissue Engineering

Background:

• Bone defects from trauma, infection, or tumors pose significant clinical challenges.
• Bone tissue engineering (BTE) offers a promising approach for bone defect repair.
• Polycaprolactone (PCL) scaffolds are widely used in BTE, but often lack osteoinductivity, while self-assembling peptides (SAPs) can mimic the extracellular matrix but have limited mechanical strength.

Purpose of the Study:

• To evaluate the efficacy of a composite implant comprising 3D-printed PCL, bone marrow mesenchymal stem cells (BMSCs), and self-assembling peptides (SAPs) for bone defect repair.
• To assess the combined effects of PCL/BMSCs/SAPs on osteogenesis, angiogenesis, and bone regeneration both in vitro and in vivo.

Main Methods:

• Fabrication of 3D-printed PCL scaffolds.
• Seeding of BMSCs and integration with SAPs to create PCL/BMSC/SAP implants.
• In vitro assessment of BMSC proliferation, osteogenesis, and conditioned medium effects on human umbilical vein endothelial cell (HUVEC) migration and angiogenesis.
• In vivo evaluation of bone regeneration and neovascularization in calvarial defects after 8 weeks of transplantation using radiography, histology, and immunohistochemistry.

Main Results:

• In vitro studies showed that PCL/SAP scaffolds enhanced BMSC proliferation and osteogenesis compared to PCL scaffolds alone.
• Conditioned medium from PCL/BMSC/SAP cultures promoted HUVEC migration and angiogenesis more effectively than from PCL/BMSC cultures.
• In vivo transplantation of PCL/BMSC/SAP implants led to significantly greater bone and blood vessel formation compared to control groups (blank, PCL, PCL/BMSC).

Conclusions:

• The combination of BMSC-seeded 3D-printed PCL scaffolds with SAPs represents an effective strategy for enhancing bone defect repair.
• The developed PCL/BMSC/SAP composite implant demonstrates potent osteogenic and angiogenic potential, promoting significant bone regeneration and neovascularization.
• This study presents a novel approach for treating bone defects by integrating PCL, BMSCs, and SAPs in a 3D-printed scaffold.