In vitro experiments on laser sintered porous pcl scaffolds with polymer hydrogel for bone repair

Bone defects caused by tumors, diseased infection, trauma or abnormal bone development create a lot of serious health problems. Tissue engineering aims to fabricate tissues or organs using patients' cells for repairing the damaged tissues or organs in clinic. The aim of this study was to design and fabricate polycaprolactone (PCL) scaffolds using the inhouse-built selective laser sintering (SLS) rapid prototyping (RP) machine and combining with polymer hydrogel for in vitro study for bone repair. In this study, three configurations of scaffolds structure (0/45/0/45°, 0/90/0/90°, and 0/45/90/135° patterns) were designed and produced. The compressive modulus, porosity and pore size of porous scaffolds were first determined. In addition, polymer hydrogel was combined with PCL scaffolds with three loading methods (i.e., immersion method, injection method and titration method) to enhance scaffolds surface hydrophilicity for cell proliferation. Mesenchymal stem cells from New Zealand White rabbits were loaded on PCL scaffolds and induced to osteoblasts in vitro. Bone formation was determined by MTS assays, von Kossa stains and ALP activities. The experimental results showed the compressive moduli of scaffolds with 0/45/0/45°, 0/90/0/90°, and 0/45/90/135° patterns was 2 MPa, 3.4 MPa, and 3.75 MPa, respectively. The porosity of scaffolds was 72%, 76%, and 83%, respectively. The ranges of pore size of scaffolds were 350400 μm, 400500 μm, and 350400 μm, respectively. By comparing three kinds of polymer hydrogel loading methods, titration method had the best result. The in vitro experimental results revealed that OD values of MTS tests and ALP activities increased from day 7 to day 21 and von Kossa stain revealed dark brown mineralized tissue, indicating cells could proliferate and differentiate in polymer hydrogel and scaffolds.