Biblioteca Virtual en Salud

BACKGROUND:

It has been confirmed that a polymer scaffold with hydroxyapatite (HA) has good biocompatibility. Chitosan that is combined with other materials, such as HA, hyaluronic acid, alginate, and potential growth factors, can be applied in tissue engineering field. Meanwhile, numerous studies have confirmed that bone morphogenetic protein-2 (BMP-2)can promote the growth of osteoblasts and induce osteogenesis in vitro and in vivo.So,can we prepare a new tissue-engineered scaffold with these four kinds of materials?

OBJECTIVE:

To prepare a novel BMP-2-loaded tissue-engineered bone scaffold using poly(lactic-co-glycolic acid) (PLGA), HA and different concentrations of chitosan, and to observe the scaffold structure, hydrophilicity, and adherence to osteoblasts as well as the optimal modification concentration of chitosan.

METHODS:

(1) A tissue-engineered scaffold containing PLGA, HA and BMP-2 was prepared using the solid-liquid phase separation and modified by chitosan (0.25%, 0.5% and 1%). Additionally, PLGA/HA and PLGA/HA/BMP-2 scaffolds were prepared as controls. Scaffold structure was observed under a scanning electron microscope. The hydrophilicity of each scaffold and BMP-2 release of the PLGA/HA/BMP-2/chitosan scaffold were examined. (2) Pre-osteoblastic suspensions were seeded onto each scaffold. Cell adhesion and proliferation were detected using cell counting kit-8 at 1, 4, 7 days of cell culture. Fluorescein diacetate was used for a vital staining of cells at 7 days of cell culture. Alkaline phosphatase activity was detected at 4, 7 and 14 days of cell culture. RESULTS AND

CONCLUSION:

(1) All the scaffolds were white beaker-shaped and had porous structure with a pore size of about 100 μm, and interconnected pores were observed under the scanning electron microscope. (2) The scaffold hydrophilicity was increased with the increasing concentration of chitosan. (3) BMP-2 cumulative release amount was 44% for the PLGA/HA/BMP-2, 34% for PLGA/HA/BMP-2/0.25% chitosan, 27% for PLGA/HA/BMP-2/0.5% chitosan, and 26% for PLGA/HA/BMP-2/1% chitosan, indicating that chitosan can effectively slow the release of BMP-2. (4) Cell viability of pre-osteoblasts seeded onto the PLGA/HA/BMP-2/0.25% chitosan scaffold was highest at 7 days of cell culture. Higher cell viability of pre-osteoblasts seeded onto the PLGA/HA/BMP-2/chitosan (0.5%, 1%) scaffolds was also observed compared with two control scaffolds. After fluorescein diacetate staining, living cells with green fluorescence were evenly distributed on the scaffolds under the confocal laser microscope. (5) The alkaline phosphatase activity in cells seeded onto different scaffolds was ranked as follows the PLGA/HA/BMP-2/0.25% chitosan scaffold > the PLGA/HA/BMP-2/0.5% chitosan scaffold > the PLGA/HA/BMP-2/1% chitosan scaffold > the PLGA/HA/BMP-2 scaffold > the PLGA/HA scaffold (P < 0.05). Taken together, the PLGA/HA/BMP-2/chitosan scaffold is suitable to release bioactive BMP-2 for stimulating cell adhesion, differentiation and proliferation, which is designed to optimize the tissue-engineered bone scaffold in bone tissue engineering strategies. And moreover, the optimal modification concentration of chitosan is 0.25%.