Fabrication And Properties Study Of Layered Biomimetic Scaffolds Coupled With Nanofibrous Membrane Calcified Layer

Articular cartilage is a kind of special connective tissue which consists of superficial zone,middle zone,deep zone and calcified zone.Because of the lack of blood vessel,lymphatic vessel and innervation,it is well known that self-repair ability of articular cartilage is very limited.Tissue engineering is a relatively new field that uses seed cells,biocompatible materials,and suitable bioactive factors to fabricate scaffolds for tissue repair or reconstruction.In this study,hydroxyapatite(HA)and chitosan/hydroxyapatite composite materials were synthesized using a coprecipitation method and were characterized by X-ray diffractometer(XRD)and transmission electron microscope(TEM).Results obtained from TEM and XRD measurements showed that HA nanoparticles had rod-like morphology with dimension 200 nm in length,and they were high dispersion and crystallinity.Pure chitosan,silk fibroin and HA nanoparticles were blended together to produce solutions with various concentrations and these solutions were electrospun under optimal conditions.The resulting nanofibrous membranes were fabricated into integral constructs that can partially mimic the calcified layer of articular cartilage.Images taken by scanning electron microscope(SEM)indicated that diameter of nanofibers was distributed in a range between about 100-300 nm,and hydroxyapatite nanoparticles were shown on the surface of fibers;and the average pore-size of these nanofibrous membranes were found less than 3 ?m.Besides these,chitosan,silk fibroin and hydroxyapatite were also used to construct other layers in the layered scaffolds via a temperature deposition processing method.The porosity and pore-sizes of other layers in the scaffolds as well as the related properties could be effectively regulated and such produced scaffolds showed well-controlled construes and properties to meet the needs of cell growth.MC3T3 cells were cultured with the leaching liquor of scaffolds at different concentrations,and the cells grown in scaffolds were also viewed by SEM.Results obtained by MTT assay and SEM images confirmed that the presently built scaffolds were able to well support the ingrowth and migration of the seeded cells.It can be concluded that these scaffold have potential in articular cartilage once they are further investigated for their in vivo performance.