Sr²⁺ Sustained Release System Augments Bioactivity of Polymer Scaffold

Abstract

Strontium ion (Sr 2+ ) enabled us to endow polymer bone scaffolds with bioactivity owing to its excellent osteoinductive capacity. Nevertheless, the burst release of Sr 2+ hindered its further application. Herein, strontium substituted hydroxyapatite (SrHA) was constructed to achieve a sustained release system. Specifically, Sr 2+ could substitute Ca 2+ in a HA lattice framework through ion exchange due to their similar ion radius. The ionic bond formed by Sr 2+ and surrounding ions could prevent the rapid escape of Sr 2+ and thereby achieve the sustained release of Sr 2+ . Subsequently, SrHA was introduced into the poly-L-lactic (PLLA) scaffold fabricated by selective laser sintering. Results demonstrated that PLLA/SrHA scaffolds presented a sustained Sr 2+ release with a cumulative concentration of 5.6 mg/L over 28 days. The released Sr 2+ significantly promoted the cell proliferation and differentiation. Furthermore, the tensile and compressive strengths of PLLA/ SrHA scaffolds were also greatly enhanced in comparison with that of PLLA scaffolds. These positive findings demonstrated that PLLA/SrHA scaffolds had considerable potential for bone repair.

In Situ Growth of a Metal–Organic Framework on Graphene Oxide for the Chemo-Photothermal Therapy of Bacterial Infection in Bone Repair

“…According to the results of the cell-based tests in vitro, the PLLA/ZIF@GO scaffold provided a beneficial environment for cell growth. Oxygen-containing functional groups of GO are known to exert a positive effect on cell behavior. , Negatively charged functional groups were able to interact with phospholipids and proteins of the cell membrane by hydrogen bonding and p–p stacking, thus promoting the adhesion and growth of the cells on the scaffold . In addition, these functional groups were hydrophilic groups.…”

Stress-Induced Dual-Phase Structure to Accelerate Degradation of the Fe Implant

“…In region 2, two different lattice planes were discovered; one was a plane (200) representing the austenite phase, and the other was a plane (101) relating to the martensite phase. Particularly, plenty of lattice stripes were distorted, as shown in Figure f,i, indicating numerous dislocation substructures in the powders. , This was also evidence for the formation of the Si solid solution in γ-austenite. These observations were consistent with XRD results (Figure a), where the diffraction peaks of γ-austenite shifted to a low angle.…”

Construction of magnetic nanochains to achieve magnetic energy coupling in scaffold

“…4 a. The pore size of the scaffold was 800 ± 50 μm, which was proven to be beneficial to cell adhesion and climbing growth [ 31 , 32 ]. The phase composition of the scaffolds was assessed using XRD (Fig.…”