Biomimetic synthesis of Mg‐substituted hydroxyapatite nanocomposites and three‐dimensional printing of composite scaffolds for bone regeneration

Abstract

In this study, we have successfully fabricated magnesium (Mg) substituted hydroxyapatite nanocomposites (Mg-HA) by utilizing type I collagen (COL I) and citric acid (CA) through a bitemplate-induced biomimetic mineralization approach. The obtained composite nanoparticles were subsequently mixed with chitosan (CHI) and gelatin (Gel) to prepare porous scaffolds with interconnected structures by three-dimensional (3D) printing technique. The Mg-HA powders and composite scaffolds were characterized. The results showed that the substitution of Mg for Ca ions reduced the crystallinity of HA crystals, but did not significantly affect the size and structure of the nanocomposites. The morphology of Mg-HA scaffolds turned smoother compared with the HA scaffolds with Mg substitution. Furthermore, the biocompatibility of Mg-HA composite scaffolds was evaluated by metal ion release, cell attachment, proliferation, and differentiation of MC3T3-E1 cells.According to the results, as the more Ca 2+ was substituted by Mg 2+ , the more Mg 2+ was released from the samples and the pH in cultured medium was more acidic. It was suggested that Mg-HA scaffolds presented higher cell attachment, proliferation rate, increased expression of alkaline phosphatase (ALP) activity and osteogenic related gene, including osteocalcin (OCN), runt-related transcription factor 2 (RUNX2), and COL I. Therefore, it was indicated that the 3D printed Mg-HA composite scaffolds with excellent biocompatibility and bioactivity were a potential candidate in bone tissue engineering.

Ion release from hydroxyapatite and substituted hydroxyapatites in different immersion liquids: in vitro experiments and theoretical modelling study

“…This confirms that Mg is released the easiest, as mentioned also in the literature [71,72]. A high release of Mg was likewise observed from Mg-HAP scaffolds in PBS [73]. This intense Mg 2+ release generally improves the substituted HAPs affinity with cells as well as their bioactivity [13,22,73].…”

Biomimetic mineralized hybrid scaffolds with antimicrobial peptides

“…This would be useful to fabricate biomimetic scaffolds applied in soft-to-hard tissue interfaces, such as tendon enthuses, ligament insertions, osteochondral zones, and periodontium [ 57 ]. Moreover, the versatility of the PILP process can be further exploited as it can be used to mineralize scaffolds with alternative nanofibrillar polymers, such as cellulose and elastin like polymers [ 58 , 59 ] or collagen fibers with calcium phosphates modified with ions, such as magnesium and strontium [ [60] , [61] , [62] ], with known osteogenic potential.…”

Additive Manufacturing Methods for Producing Hydroxyapatite and Hydroxyapatite-Based Composite Scaffolds: A Review

“…Although HAp chemical composition is similar to the mineral phase of native bone tissue, it was observed that stoichiometric HAp has no other valuable trace ions (e.g., Si 4+ , Sr 2+ , and Mg 2+ ), which are regularly found in natural hard tissues (Yilmaz et al, 2018). Therefore, the synthesis and use of HAp doped with therapeutic ions in the form of 3D scaffolds have been carried out to make more effective HAp-based bone substitutes (Luo et al, 2018;Chen et al, 2019b). Recently, 3D-printed PCL/Srdoped HAp scaffolds were used for enhanced bone regeneration in the cranial defect of rats (Liu Y. S. et al, 2019).…”