Bioactive Nanocomposite Microsponges for Effective Reconstruction of Critical-Sized Calvarial Defects in Rat Model

Abstract

Micro-sized sponge particulates have attracted extensive attention because of their potential to overcome the intrinsic limitations of conventional monolithic scaffolds in tissue engineering. Bioactive nanocomposite microsponges are regarded as potential bone substitute materials for bone regeneration. Methods: Based on a combination of microfluidic emulsion with further freezing and in situ thawing, chitosan (CS)-hydroxyapatite (HAP) microsponges were prepared and characterized in terms of their morphology and elemental distribution using a scanning electron microscope equipped with an X-ray detector. The swelling ratio, porosity, degradability, antibacterial activity, and bioactivity were detected and analyzed. The biological functions of the CS-HAP microsponges were examined to assess the adhesion, proliferation, and differentiation of in vitro co-cultured rat bone marrow mesenchymal stem cells (rBMSCs). Furthermore, the CS-HAP microsponges were used as cell-free scaffolds and implanted into calvarial defects in a rat model to evaluate the in vivo osteogenesis. Results: The CS-HAP microsponges have a porous structure with high porosity (~76%), good swelling capacity (~1900%), and shape-memory properties. The results of in vitro experiments show that the CS-HAP microsponges achieve good bioactivity and promote osteogenic differentiation of rBMSCs. Furthermore, the CS-HAP microsponges significantly promote bone regeneration in rat calvarial defects. Conclusion:The bioactive CS-HAP microsponges have the potential to be used as bone substitute materials for bone tissue engineering.

Strontium Ion-Functionalized Nano-Hydroxyapatite/Chitosan Composite Microspheres Promote Osteogenesis and Angiogenesis for Bone Regeneration

“…At the same time point, the amount of mineralized crystals in nHA/CS@PDA and nHA/CS@PDA-Sr was excess to nHA/CS (Figure H). Wang et al reported that hydroxyapatite/chitosan composite microsponges possess a good mineralization ability . The reason for the better mineralization of the composite microspheres possessing PDA coating may be that the catechol structure of dopamine is a strong coordination bond of metal ions, which is more favorable to the formation of apatite …”

“…The cells were incubated in a humidified atmosphere with 5% CO 2 at 37 °C. The fresh culture medium was replaced every 2–3 days . The Cell Counting Kit-8 (CCK-8, Dojindo, Kumamoto, Japan) was used to evaluate the proliferation of HUVECs and BMSCs.…”

“…The fresh culture medium was replaced every 2−3 days. 53 The Cell Counting Kit-8 (CCK-8, Dojindo, Kumamoto, Japan) was used to evaluate the proliferation of HUVECs and BMSCs. For this assay, 1 × 10 4 HUVECs and BMSCs were seeded in the 24-well plates and incubated for 24 h. Then, the composite microspheres were added to the plates.…”

Properties of Calcium Phosphate/Hydrogel Bone Grafting Composite on the Model of Diaphyseal Rat Femur’s Defect: Experimental Study

“…Критические дефекты, описанные в литерату ре, условно можно разделить на два типа. К перво му типу можно отнести дефекты, не требующие в силу своей стабильности дополнительной ауг ментации, профилактически предотвращающей патологический перелом оперируемой кости (округлые фрезевые дефекты черепа [25,30,31], округлые фрезевые дефекты эпифизов бедренной и большеберцовой костей [28]). Ко второму типу от носятся дефекты, требующие стабилизации ввиду высокого риска переломов костей при обычной на грузке -полные сегментарные дефекты бедрен ной кости, фиксированные штифтом [22], пласти ной [32] или аппаратом наружной фиксации [33].…”