A poly(lactide‐co‐glycolide)/hydroxyapatite composite scaffold with enhanced osteoconductivity

Abstract

Biodegradable polymer/ceramic scaffolds can overcome the limitations of conventional ceramic bone substitutes. However, the conventional methods of polymer/ceramic scaffold fabrication often use organic solvents, which might be harmful to cells or tissues. Moreover, scaffolds fabricated with the conventional methods have limited ceramic exposure on the scaffold surface since the polymer solution envelopes the ceramic particles during the fabrication process. In this study, we developed a novel fabrication method for the efficient exposure of ceramic onto the scaffold surface, which would enhance the osteoconductivity and wettability of the scaffold. Poly(D,Llactide-co-glycolide)/nanohydroxyapatite (PLGA/HA) scaffolds were fabricated by the gas foaming and particulate leaching (GF/PL) method without the use of organic solvents. Selective staining of ceramic particles indicated that HA nanoparticles exposed to the scaffold surface were observed more abundantly in the GF/PL scaffold than in the conventional solvent casting and particulate leaching (SC/PL) scaffold. Both types of scaffolds were implanted to critical size defects in rat skulls for 8 weeks. The GF/PL scaffolds exhibited significantly enhanced bone regeneration when compared with the SC/PL scaffolds. Histological analyses and microcomputed tomography of the regenerated tissues showed that bone formation was more extensive on the GF/PL scaffolds than on the SC/PL scaffolds. Compared with the SC/PL scaffolds, the enhanced bone formation on the GF/PL scaffolds may result from the higher exposure of HA nanoparticles to the scaffold surface. These results show that the biodegradable polymer/ceramic composite scaffolds fabricated with the novel GF/PL method can enhance bone regeneration compared with those fabricated with the conventional SC/PL method.

Physical properties and cellular responses to crosslinkable poly(propylene fumarate)/hydroxyapatite nanocomposites

“…The minimum value was found on the PPF/HA disk with 30% HA at 34.9±3.7°. These results show that the incorporation of HA nanoparticles with crosslinked PPF increases the hydrophilicity on their surfaces, in agreement with previous studies on other biodegradable synthetic polymer matrixes [15,41].…”

“…However, it is very brittle and cannot be applied to the load-bearing site directly [3][4][5]. To overcome these limitations, HA has been incorporated with natural biomacromolecules such as collagen [6][7][8] and gelatin [9,10], or synthetic polymers such as poly (α-hydroxyl acids) [11][12][13][14][15], poly (ε-caprolactone) (PCL) [16,17], polyamide [18], and polymethylmethacrylate (PMMA) [19] to prepare composites using a variety of methods including surface coating, grafting, direct mixing, and biomimetic precipitation [10,11,[20][21][22][23]. Particularly, polymer/HA nanocomposites have improved mechanical properties and enhanced cell attachment, spreading, and proliferation on their surfaces by adding nano-sized HA to modify the polymer's characteristics and/or strengthen the polymer matrix [24,25].…”

Calcium orthophosphate-based biocomposites and hybrid biomaterials

“…Currently, they provide with a good choice when a suitable polymeric filler material is sought. For example, HA/PLGA composites were developed, which appeared to possess a cellular-compatibility suitable for bone tissue regeneration [301][302][303][304][305][306][307][308]. Zhang and Ma [48,233] seeded highly porous PLLA foams with HA particles in order to improve the osteoconductivity of polymer scaffolds for bone tissue engineering.…”

Augmentation of bone defect healing using a new biocomposite scaffold: An in vivo study in sheep

“…However, despite allowing deformation of the scaffold, which is necessary for application in total knee revision, these polymer scaffolds do not offer good enough mechanical properties to resist significant loadings. To overcome this mechanical drawback ceramic-polymer composites have gained increasing interest [6][7][8]. In particular, a biocomposite of controlled porosity combining b-tricalcium phosphate (b-TCP) and poly(L-lactic acid) (PLA) was obtained by supercritical gas foaming [9].…”