RESUMEN
The effective regeneration of large bone defects via bone tissue engineering is challenging due to the difficulty in creating an osteogenic microenvironment. Inspired by the fibrillar architecture of the natural extracellular matrix, we developed a nanoscale bioengineering strategy to produce bone fibril-like composite scaffolds with enhanced osteogenic capability. To activate the surface for biofunctionalization, self-adaptive ridge-like nanolamellae were constructed on poly(ε-caprolactone) (PCL) electrospinning scaffolds via surface-directed epitaxial crystallization. This unique nanotopography with a markedly increased specific surface area offered abundant nucleation sites for Ca2+ recruitment, leading to a 5-fold greater deposition weight of hydroxyapatite than that of the pristine PCL scaffold under stimulated physiological conditions. Bone marrow mesenchymal stem cells (BMSCs) cultured on bone fibril-like scaffolds exhibited enhanced adhesion, proliferation, and osteogenic differentiation in vitro. In a rat calvarial defect model, the bone fibril-like scaffold significantly accelerated bone regeneration, as evidenced by micro-CT, histological histological and immunofluorescence staining. This work provides the way for recapitulating the osteogenic microenvironment in tissue-engineered scaffolds for bone repair.
RESUMEN
Periodontitis is a worldwide bacterial infectious disease, resulting in the resorption of tooth-supporting structures. Biodegradable polymeric microspheres are emerging as an appealing local therapy candidate for periodontal defect regeneration but suffer from tedious procedures and low yields. Herein, we developed a facile yet scalable approach to prepare polylactide composite microspheres with outstanding drug-loading capability. It was realized by blending equimolar polylactide enantiomers at the temperature between the melting point of homocrystallites and stereocomplex (sc) crystallites, enabling the precipitation of sc crystallites in the form of microspheres. Meanwhile, epigallocatechin gallate (EGCG) and nano-hydroxyapatite were encapsulated in the microspheres in the designated amount. Such an assembly allowed the fast and sustained release of EGCG and Ca2+ ions. The resultant hybrid composite microspheres not only exhibited strong antimicrobial activity against typical oral pathogens (Porphyromonas gingivalis and Enterococcus faecalis), but also directly promoted osteogenic differentiation of periodontal ligament stem cells with good cytocompatibility. These dual-functional composite microspheres offer a desired drug delivery platform to address the practical needs for periodontitis treatment.
