Complementary and Synergistic Design of Bi‐Layered Double Hydroxides Modified Magnesium Alloy toward Multifunctional Orthopedic Implants

Abstract

Magnesium (Mg)-based alloys have been regarded as promising implants for future clinic orthopedics, however, how to endow them with good anti-corrosion and biofunctions still remains a great challenge, especially for complicated bone diseases. Herein, three transition metals (M = Mn, Fe, and Co)-containing layered double hydroxides (LDH) (LDH-Mn, LDH-Fe, and LDH-Co) with similar M content are prepared on Mg alloy via a novel two-step method, then systematic characterizations and comparisons are conducted in detail. Results showed that LDH-Mn exhibited the best corrosion resistance, LDH-Mn and LDH-Co possessed excellent photothermal and enzymatic activities, LDH-Fe revealed better cytocompatibility and antibacterial properties, while LDH-Co demonstrated high cytotoxicity. Based on these results, an optimized bilayer LDH coating enriched with Fe and Mn (LDH-MnFe) from top to bottom have been designed for further in vitro and in vivo analysis. The top Fe-riched layer provided biocompatibility and antibacterial properties, while the bottom Mn-riced layer provided excellent anti-corrosion, photothermal and enzymatic effects. In addition, the released Mg, Fe, and Mn ions have a positive influence on angiogenesis and osteogenesis. Thus, the LDH-MnFe showed complementary and synergistic effects on anti-corrosion and multibiofunctions (antibacteria, antitumor, and osteogenesis). The present work offers a novel multifunctional Mg-based implant for treating bone diseases.

Layered Double Hydroxides: A Novel Promising 2D Nanomaterial for Bone Diseases Treatment

“…In another study, Mn-based LDH was identified to possess better corrosion resistance in comparison with Fe-based LDH and Co-based LDH (Figure 4g). [147] The released metal cations and interlayer anions depending on the degradation behaviors contribute to the bioactivity of LDHs. As an alkaline 2D nanomaterial, LDHs possess acidresponsive degradation properties and tend to degrade faster in acidic environments, which benefits targeted drug delivery as acidic or H 2 O 2 -riched microenvironment is more commonly observed in bone infections, bone tumors, and osteoarthritis circumstances.…”

“…Segura-Pérez et al [221] reported a novel bone implant composed of HA and LDHs with different metal compositions, where significant bacteriostatic effects against clinical multi-resistant bacteria under a very low minimum inhibitory concentration (0.5 mg mL −1 ) were observed in Cu-based LDHs. Zhang et al [147] compared the antibacterial efficiency of Mg alloy coated with Mn-based LDH, Fe-based LDH, and Co-based LDH. It turned out that Fe-based LDH possessed the best antibacterial properties and Mn-based LDH revealed excellent photothermal and enzymatic activities.…”

“…Reproduced with permission. [ 147 ] Copyright 2022, John Wiley and Sons. PVA, poly(vinyl alcohol); PAM, polyacrylamide; CS, chitosan/silk fibroin; PEO, plasma electrolytic oxidation; EIS, electrochemical impedance spectroscopy.…”

“…g) Corrosion morphologies of PEO, LDH-Mn, LDH-Fe, and LDH-Co after 4 and 14 days of immersion. Reproduced with permission [147]. Copyright 2022, John Wiley and Sons.…”

Layered Double Hydroxides as the Unique Product of Target Ionic Construction for Energy, Chemical, Foods, Cosmetics, Medicine and Ecology Applications

“…Recent studies [201] propose to formation of multilayer LDH coatings with different effects on implantable magnesium alloys. Thus, the lower layer of Mn‐LDH adjacent to the metal plate provides corrosion protection for the implant, and iron‐saturated Fe‐LDH external layer provides high biocompatibility and antimicrobial properties; at the same time, metal ions released during the slow decomposition of LDH have a positive effect on angiogenesis and osteogenesis.…”