Evaluation of zinc-doped mesoporous hydroxyapatite microspheres for the construction of a novel biomimetic scaffold optimized for bone augmentation

Abstract

Biomaterials with high osteogenic activity are desirable for sufficient healing of bone defects resulting from trauma, tumor, infection, and congenital abnormalities. Synthetic materials mimicking the structure and composition of human trabecular bone are of considerable potential in bone augmentation. In the present study, a zinc (Zn)-doped mesoporous hydroxyapatite microspheres (Zn-MHMs)/collagen scaffold (Zn-MHMs/Coll) was developed through a lyophilization fabrication process and designed to mimic the trabecular bone. The Zn-MHMs were synthesized through a microwave-hydrothermal method by using creatine phosphate as an organic phosphorus source. Zn-MHMs that consist of hydroxyapatite nanosheets showed relatively uniform spherical morphology, mesoporous hollow structure, high specific surface area, and homogeneous Zn distribution. They were additionally investigated as a drug nanocarrier, which was efficient in drug delivery and presented a pH-responsive drug release behavior. Furthermore, they were incorporated into the collagen matrix to construct a biomimetic scaffold optimized for bone tissue regeneration. The Zn-MHMs/Coll scaffolds showed an interconnected pore structure in the range of 100–300 μm and a sustained release of Zn ions. More importantly, the Zn-MHMs/Coll scaffolds could enhance the osteogenic differentiation of rat bone marrow-derived mesenchymal stem cells. Finally, the bone defect repair results of critical-sized femoral condyle defect rat model demonstrated that the Zn-MHMs/Coll scaffolds could enhance bone regeneration compared with the Coll or MHMs/Coll scaffolds. The results suggest that the biomimetic Zn-MHMs/Coll scaffolds may be of enormous potential in bone repair and regeneration.

The Prospects of Zinc as a Structural Material for Biodegradable Implants—A Review Paper

“…According to Zhu et al [70], Zn biomaterial can support hMSC adhesion and proliferation and zinc ions can lead to enhanced regulation of genes, cell survival/growth and differentiation, extracellular matrix (ECM) mineralization, and osteogenesis. The stimulation of osteogenesis by ionic zinc has been supported by numerous studies [71][72][73][74][75][76][77][78][79]. In the case of human vascular cells, Zn 2+ at low concentrations can enhance cell viability, proliferation, adhesion, spreading, migration, and F-actin and vinculin expression, while decreasing cell adhesion strength.…”

Bibliographic review on the state of the art of strontium and zinc based regenerative therapies. Recent developments and clinical applications

“…Four scaffolds named: collagen (Coll) scaffold, MHM/Coll scaffold, Zn2-MHM/Coll scaffold, and Zn5-MHM/Coll were prepared and tested on an in vivo rat model. 98 Analogously, strontium polyphosphate microparticles (Sr-a-polyP-MP) were analysed to induce mineralization of bone cells in comparison to calcium polyphosphate microparticles (Ca-a-polyP-MP) and b-tricalcium phosphate (b-TCP), which were applied to Sarcoma Osteogenic cells (SAOS-2) and hMSC cells. These MPs were encapsulated in PGLA microspheres (MS), which leaves them with three samples to contrast: b-TCP-MS, Ca-a-polyP-MS, 99 and lastly, SR loaded PGLA microspheres (PM), where PGLA was degraded by hydrolysis into lactic and glycolic acid, which can develop into an inflammatory response.…”

Glancing Angle Deposition of Zn-Doped Calcium Phosphate Coatings by RF Magnetron Sputtering

“…Modern approaches to healthcare are aiming to produce implants with biomimetic properties [16]. These properties are crucial to ensuring a desirable biological response to the newly implanted material, in such a manner that the cells, which are adhered to the surface of such scaffolds, can function in a way that is similar to physiological conditions.…”