Functionalized high entropy alloys with ZIF-8 and LDH nanolayers for next-generation drug eluting medical implants

In this study, high entropy alloys (HEA) were fabricated by mixing Ni, Co, Cr, Fe, and Mn powders and then subjected to spark plasma sintering (SPS). Samples were coated by Al-Zn-layered double hydroxide (LDH) nanoparticles (NPs), SiO2 coated Al-Zn-layered double hydroxide NPs (LDH@Sio2), and zeolite imidazole framework (ZIF-8 NPs) using the electrophoretic deposition (EPD) method. To enhance immune response, antiviral effects, and iron uptake, ascorbic acid was intercalated within LDHs and ZIF-8 NPs layers via the ion-exchange method. Microstructural properties were examined using the X-ray diffraction method (XRD), optical microscopy, and scanning electron microscopy (SEM). The corrosion behavior of the specimens was investigated by a potentiodynamic polarization scan (PDS). A UV-visible evaluation test was conducted to assess drug release from the coated samples. SEM images demonstrated a homogenous microstructural coating, and XRD results confirmed that successful incorporation of vitamin C into LDH NPs, as indicated by an increase in layer distance from 7.36 to 7.46 Å. UV-visible studies revealed that LDH@SiO2 NPs exhibited a vitamin C release rate exceeding 5% compared to other coatings. Cell adhesion and proliferation assays using the MTT assay further confirmed the biocompatibility of the samples and their appropriate biological response to MG63 cells.