This study uses a nano-hydroxyapatite/chitosan/poly(lactide-co-glycolide) (nHA/CS/PLGA) scaffold which is seeded with human umbilical cord mesenchymal stem cells for bone tissue engineering in order to allow for repair of bone defects. Tissue engineering uses basic concepts from materials engineering and life sciences and applies them to health care needs in order to design replacement devices with similar morphology and function of injured tissues to allow for tissue repair. A common compound that is used in bone tissue engineering involves PLGA as it is biocompatible, non-toxic, and relatively anti-inflammatory. It is also useful because it can be manipulated in order to vary its biodegradation rate, allowing it to be used for many applications in vivo for varying periods of time. Chitosan is also often used because it is a natural material that can be completely reabsorbed by the body. Because of this, it is able to function in the body and interact with cells in order to facilitate adhesion, differentiation, and proliferation of cells. Hydroxyapatite is found in human bone, a highly desirable facet of this compound, as it allows for high rates of biocompatibility and bioactivity. When each of these materials is combined to create a new mixture, the properties also combine and allow for improved bioactivity, biodegradation, and mechanical properties. The study conducted by Wang et al. focuses on using human umbilical cord mesenchymal stem cells (hUCMSC) along with a nHA/CS/PLGA scaffold to determine how the use of such cells would affect osteogenic differentiation of the scaffold.
MATERIALS AND METHODS
The engineered scaffold was formed by mixing nHA, CS, and PLGA. PLGA was first dissolved completely in chloroform and then nHA and CS were add sequentially. Sodium chloride was also added to this solution and then the mixture was put through ultrasonic degassing and poured into a mold where it rested for 24 to 48 hours. Once shaped into the mold, it was dried for another 24 hours until it solidified completely. The scaffold had the dimension of 0.3x0.3x0.5 cm.
Through the use of scanning electron microscopy (SEM), the porosity of the scaffold was observed. The physical properties were measured through compressive and tensile tests with a constant strain rate of 1 mm/min. Ten umbilical cords were used from babies that had been delivered in a similar fashion and at identical rates of development. These cells were cultured and incubated in the same media. After three weeks, the cells were studied for adipogenesis and chondrogenesis activity through use of staining. Cells were also injected into the scaffolds and cultured in osteogenic media. Cell proliferation on these scaffolds was measured through use of an MTT assay. After being injected with the MTT solution, the scaffolds were incubated for four hours and the media was removed.
In vivo studies were also conducted with the engineered scaffolds. The scaffolds were cultured for fourteen...