Effects of preparation methods on the bone formation potential of apatite-coated chitosan microspheres

Abstract

To investigate the effects of preparation methods on the bone formation potential of apatite-coated chitosan microspheres, coacervate precipitation method and emulsion cross-linking method were chosen to prepare chitosan microspheres, and then apatite coatings were deposited using simulated body fluid. Rat bone marrow-derived mesenchymal stem cells (BMSCs) were seeded on these microspheres. Cell adhesion, proliferation, and differentiation potential were monitored. For in vivo analysis, some cell/microsphere constructs were implanted in the subcutaneous pockets of male Wistar rats. After 3, 6, 12 weeks, the samples were retrieved and stained with hematoxylin and eosin (HE). Some cell/microsphere constructs were implanted in the calvarial defects of rats. Micro-CT and HE analysis were performed to analyze the new bone formation. It was found that BMSCs on apatite-coated emulsion cross-linked microspheres (EM1) exhibited better proliferation and differentiation than cells on apatite-coated coacervate-precipitated microspheres. The in vivo results showed that no bone was observed in ectopic areas. While in calvarial defects, both histological slices and Micro-CT images demonstrated that a substantial amount of new bone was formed in the EM1/BMSCs construct. These data suggest that preparation methods do exert great influence on the in vitro cell behaviors and in vivo orthotopic bone regeneration of apatite-coated chitosan microspheres. Appropriate method should be considered when preparing chitosan microspheres for bone tissue engineering scaffold.

Construction of Radial Defect Models in Rabbits to Determine the Critical Size Defects

“…Periosteal reaction and thick new bone-like tissues were found at the bottom of the defects. Osteoblasts and chondroblasts could be detected in all five groups (red and blue arrow, Fig 7 ), which showed this area should be immature bone tissue, i.e., this part should be the new bone tissue [ 33 – 34 ]. The central defect size was reduced with the increase of created defect size ( Fig 8 ).…”

Polysaccharide-Based Materials Created by Physical Processes: From Preparation to Biomedical Applications

“…Polysaccharide-based precipitates can be quickly and easily prepared by combining an aqueous solution of a polycation (e.g., chitosan and proteins [ 159 , 160 ]) with an aqueous solution containing a polyanion (e.g., glycosaminoglycans, alginate, κ -carrageenan [ 161 ], and gums [ 162 ]). This strategy can prepare nanoparticles, microparticles [ 163 ], beads [ 87 ], and porous hydrogels, following a one-step method in situ. Polysaccharide-based complexes are mainly used as DDSs and scaffold matrices.…”

“…Chitosan microparticles can easily be prepared by dropping aqueous chitosan solutions into alkaline solutions. In this case, particles are created by precipitation, as chitosan is insoluble at a high pH [ 163 ].…”

Chitosan-Based Biomimetically Mineralized Composite Materials in Human Hard Tissue Repair

“…One way is to mix inorganic substances into chitosan by simple mechanical blending, such as ultrasonic dispersion, and then obtaining the final composite material by freeze-drying [ 40 , 41 , 42 ]. Nevertheless, the composite material prepared in this way is uneven and heterogeneous due to particle aggregation and a lack of intermolecular interaction between the organic matrix and the inorganics [ 43 ]. Another way is to prepare the inorganic layer in situ on the surface of the chitosan scaffold, which acts as a template [ 44 , 45 , 46 ].…”