Biomimetic Self-Assembling Metal–Organic Architectures with Non-Iridescent Structural Coloration for Synergetic Antibacterial and Osteogenic Activity of Implants

Abstract

Materials in nature feature versatile and programmable interactions to render macroscopic architectures with multiscale structural arrangements. By rationally combining metal–carboxylate and metal–organophosphate coordination interactions, Au25(MHA)18 (MHA, 6-mercaptohexanoic acid) nanocluster self-assembled structural color coating films and phytic acid (PA)–metal coordination complexes are sequentially constructed on the surface of titanium implants. The Lewis acid–base coordination principle applies for these metal–organic coordination networks. The isotropic arrangement of nanoclusters with a short-range order is investigated via grazing incidence wide-angle X-ray scattering. The integration of robust M–O (M = Ti, Zr, Hf) and labile Cu–O coordination bonds with high connectivity of Au25(MHA)18 nanoclusters enables these artificial photonic structures to achieve a combination of mechanical stability and bacteriostatic activity. Moreover, the colorless and transparent PA–metal complex layer allows the viewing of the structural color and surface wettability switching to hydrophilic and makes feasible the interfacial biomineralization of hydroxyapatite. Collectively, these modular metal–organic coordination-driven assemblies are predictive and rational material design strategies with tunable hierarchy and diversity. The complete metal–organic architectures will not only help improve the physicochemical properties of the bone–implant interface with synergistic antibacterial and osseointegration activities but also can boost surface engineering of medical metal implants

Ultrasmall PtAu2 nanoclusters activate endogenous anti-inflammatory and anti-oxidative systems to prevent inflammatory osteolysis

“…Nanocluster cores can be homometallic (e.g., Au, Ag, Cu, and Pt) or heterometallic with discrete energy levels, which can endow nanoclusters with unique chemical, biological, optical, and electronic properties [16]. For example, Au clusters have been widely studied for the diagnosis and therapy of inflammation, cancer, implant-associated infections, and COVID-19 [20][21][22][23][24][25][26][27][28], whereas heterometallic or alloy nanoclusters, such as Pt-Au clusters, have been reported to improve the physicochemical and biological performance of cancer therapies compared to homometallic nanoclusters [29,30]. The enhanced biomedical activity of heterometallic or alloy clusters is probably due to their improved stability and structural diversity resulting from the complementary advantages of different metal ions, which can favorably bind to proteins and enzymes and exert biological effects.…”

Metal–organic framework-based platforms for implantation applications: recent advances and challenges

“…1b). 26 They initially constructed a Au 25 (MHA) 18 nanocluster coating with self-assembled amorphous photonic structure on an implant surface, which provides a visual indication of the structural integrity of the implant. Then, a phytic acid (PA) metal coordination complex was further constructed at the coating-bone interface to promote the conversion of surface wettability and interface hydroxyapatite biomineralization.…”

Dynamical Integration of Antimicrobial, Anti‐Inflammatory, and Pro‐Osteogenic Activities on Polyetheretherketone via a Porous N‐Halamine Polymeric Coating

“…Highly hydrophilic surfaces could promote the proliferation and differentiation of osteogenic cells, as well as the interfacial biomineralization of hydroxyapatite. [41] Amino groups could serve as anchor points for serum proteins and growth factors, further promoting adhesion of osteogenic cells and activating osteogenic signaling pathway. [42][43][44] Additionally, the amino-rich surface might have a strong electrostatic interaction with the initial nuclei of hydroxyapatite, resulting in superior apatite-forming activity.…”