Accelerated Bonelike Apatite Growth on Porous Polymer/Ceramic Composite Scaffolds in Vitro

Abstract

Although biodegradable polymer/ceramic composite scaffolds can overcome the limitations of conventional ceramic bone substitutes, the osteogenic potential of these scaffolds needs to be further enhanced for efficient bone tissue engineering. In this study, bonelike apatite was efficiently coated onto the scaffold surface by using polymer/ceramic composite scaffolds instead of polymer scaffolds and by using an accelerated biomimetic process to enhance the osteogenic potential of the scaffold. The creation of bonelike, apatite-coated polymer scaffold was achieved by incubating the scaffolds in simulated body fluid (SBF). The apatite growth on porous poly(D,L-lactic-co-glycolic acid)/nanohydroxyapatite (PLGA/ HA) composite scaffolds was significantly faster than on porous PLGA scaffolds. In addition, the distribution of coated apatite was more uniform on PLGA/HA scaffolds than on PLGA scaffolds. After a 5-day incubation period, the mass of apatite coated onto PLGA/HA scaffolds incubated in 5 x SBF was 2.3-fold higher than PLGA/HA scaffolds incubated in 1 x SBF. Furthermore, when the scaffolds were incubated in 5 x SBF for 5 days, the mass of apatite coated onto PLGA/HA scaffolds was 4.5-fold higher than PLGA scaffolds. These results indicate that the biomimetic apatite coating can be accelerated by using a polymer/ceramic composite scaffold and concentrated SBF. When seeded with osteoblasts, the apatite-coated PLGA/HA scaffolds exhibited significantly higher cell growth, alkaline phosphatase activity, and mineralization in vitro compared to the apatite-coated PLGA scaffolds. Therefore, the apatite-coated PLGA/HA scaffolds may provide enhanced osteogenic potential when used as scaffold for bone tissue engineering.

Influence of a novel calcium-phosphate coating on the mechanical properties of highly porous collagen scaffolds for bone repair

“…Composite scaffolds using synthetic polymers and ceramic phases have been produced in the recent years (Kim et al 2006, Maeda et al 2006. However, as each scaffold consists of some phase which is not found naturally in the human body, they have all exhibited drawbacks with biocompatibility, biodegradability or osteconductivity (Rezwan et al 2006).…”

Comparison of Osteogenic Potential Between Apatite-Coated Poly(Lactide-Co-Glycolide)/Hydroxyapatite Particulates and Bio-Oss

“…In our previous study, we introduced HA nanoparticles onto a PLGA scaffold and observed an accelerated apatite coating process on the PLGA surface 20) .…”

“…HA nanoparticles 20,30) , thereby allowing fabrication of apatite-coated particulates through SBF incubating. In our previous study, we introduced HA nanoparticles onto a PLGA scaffold and observed an accelerated apatite coating process on the PLGA surface 20) .…”

“…SBF was prepared by dissolving reagent grade NaCl, NaHCO3, Na2SO4, KCl, K2HPO4, MgCl2·6H2O, and CaCl2·2H2O (Sigma, St. Louis, MO, USA) in distilled deionized water, as described previously 20,23) . The pH of the solution was adjusted to 6.4 with tris (hydroxymethyl)aminomethane (Sigma, St. Louis, MO, USA) and hydrochloric acid.…”

“…We previously fabricated a porous poly(lactic-co-glycolic acid)/ hydroxyapatite (PLGA/HA) scaffold with HA highly exposed to the scaffold surface 19) . The fabricated PLGA/HA scaffold accelerated the apatite coating process on the scaffold surface when incubated in a simulated body fluid (SBF), thereby further improving the osteogenic potential of the scaffold when compared to conventional polymer/ceramic composite scaffolds 20) . In this study, we used a critical-size cranial defect rat model to compare the osteogenic potential of apatite-coated PLGA/HA composite with that of Bio-Oss ® , a deproteinized bovine bone that is clinically used in bone regeneration procedures.…”