Seok-Jung Hong

Preparation of porous bioactive ceramic microspheres and in vitro osteoblastic culturing for tissue engineering application

Microparticulates are useful for directly filling defective tissues as well as for delivering cells and bioactive molecules in regenerative medicine. This paper reports on the production of bioactive ceramic microspheres with an interconnected macropore structure. The sol-gel derived calcium silicate powder was homogenized with an oligomeric Camphene melt, which was used as a novel porogen, and spherical-shaped microparticulates were obtained by an oil-in-water emulsion method. A porous structure was generated through the sublimation of Camphene within the calcium silicate-Camphene solidified blend under ambient conditions. The microspheres retained the crystalline phase of apatite and wollastonite during heat treatment and induced calcium phosphate precipitation under a body-simulating medium, showing the characteristics of bone-bioactive materials. Osteoblastic cells were observed to anchor to and spread well over the surface of the porous microspheres, and further to proliferate actively with culturing time. The bioactive and porous microspheres developed are considered potentially useful in the regeneration of hard tissues as a matrix for tissue engineering as well as a direct filling material.

Novel Scaffolds of Collagen with Bioactive Nanofiller for the Osteogenic Stimulation of Bone Marrow Stromal Cells

The properties of scaffolds and their roles in regulating functions of tissue cells are considered to be of utmost importance in the successful recovery of damaged tissues. Herein, novel scaffolds of collagen and bioactive inorganic nanofiller were produced for bone tissue engineering. In addition, the in vitro responses of bone marrow-derived stromal cells (BMSCs) on these scaffolds were investigated. Glasses with bioactive compositions were prepared in nanofibrous form and homogenized with a collagen to produce hybridized porous scaffolds. The glass fibrous filaments with diameters of a few hundred nanometers were embedded well within the collagen network, characterizing a typical nanocomposite. The scaffolds showed the characteristics of a hydrogel with remarkable water uptake and swelling degree, which were similar to those of the pure collagen. In addition, the scaffolds induced the precipitation of bone-like minerals on the surface under a body-simulating medium, showing the sign of in vitro bone bioactivity. BMSCs adhered and spread well over the scaffold surface and migrated deep into the scaffold network. The osteogenic marker, alkaline phosphatase, was strongly expressed on the hybrid scaffolds, with the level higher than that on pure collagen. Overall, the collagen—inorganic nanofiller scaffolds are considered to find potential utility in bone tissue engineering.