Magnesium (Mg)-based scaffolds are garnering increasing attention as bone repair materials owing to their biodegradability and mechanical resemblance to natural bone. Their effectiveness can be augmented by incorporating surface coatings to meet clinical needs. However, the limited bonding strength and unclear mechanisms of these coatings have impeded the clinical utility of scaffolds. To address these issues, this study introduces a composite coating of high-bonding-strength polydopamine-microarc oxidation (PDA-MHA) on Mg-based scaffolds. The results showed that the PDA-MHA coating achieved a bonding strength of 40.56 ± 1.426 MPa with the Mg scaffold surface, effectively enhancing hydrophilicity and controlling degradation rates. Furthermore, the scaffold facilitated bone regeneration by influencing osteogenic markers such as RUNX-2, OPN, OCN, and VEGF. Transcriptomic analyses further demonstrated that the PDA-MHA/Mg scaffold upregulated carboxypeptidase Z expression and activated the Wnt-4/β-catenin signaling pathway, thereby promoting bone regeneration. Overall, this study demonstrated that PDA can synergistically enhance bone repair with Mg scaffold, broadening the application scenarios of Mg and PDA in the field of biomaterials. Moreover, this study provides a theoretical underpinning for the application and clinical translation of Mg-based scaffolds in bone tissue engineering endeavors.
An alarming worldwide increase in microbial resistance to traditional drugs and classical pharmacophores has spurred the search for new antimicrobial compounds. Antimicrobial photodynamic therapy (aPDT) has recently emerged as an effective modality for the selective destruction of bacteria and other pathogenic microorganisms. However, some of the factors, including the aggregation of the hydrophobic photosensitizer (PS) in aqueous media and the inefficient biodistribution of PS limit its expansion to clinical conditions. In addition, the photoactivation under visible-light irradiation limits the therapeutic effect of aPDT for deep-tissue infection. To overcome these limitations, a PS (β-carboxyphthalocyanine zinc, CPZ) delivery system with lanthanide-doped upconversion nanoparticles (UCNPs, LiYF4:Yb/Er) and polyvinylpyrrolidone (PVP) was prepared and its antimicrobial (antibacterial and antifungal) activities were investigated. Such a near-infrared (NIR) triggered UCNPs-CPZ-PVP system significantly reduced the aggregation of CPZ and presented a high anti-infectious activity against multi-drug resistant (MDR) bacteria (methicillin-resistant Staphylococcus aureus by 4.7 log10 and MDR Escherichia coli by 2.1 log10) post aPDT (at 50 μg mL−1 UCNPs-CPZ-PVP with 0.5 W cm−2 980 nm light). In particular, UCNPs-CPZ-PVP showed high antifungal efficacy against Candida albicans. In vivo aPDT experiments were further carried out using an MDR bacterial infection murine model in the presence of 5 mm thick tissue specimens, demonstrating the great potential of UCNPs-CPZ-PVP against infections in deep tissue. Altogether, we reveal an efficient NIR-triggered nano-photosensitizer with promising antifungal and antibacterial efficacy for clinical antimicrobial therapy.
危险品化学品经营许可证（带存储）