Biocompatibility assessment of modified hypoeutectic 354 aluminum alloy for potential dental and orthopedic applications: an in-vitro study

Although aluminum (Al) alloys are rarely used in orthopedics, their low density and low cost warrant research into their suitability for biocompatible applications. This study compared a typical 354 aluminum alloy with a modified version (M354) containing 0.35 wt% Zr and 0.14 wt% Ni. Both alloys were inspected using optical micrographs. Field Emission Microscopy with Energy-Dispersive X-ray (FE-SEM/EDX) and Atomic Force Microscopy (AFM) were used to analyze the surfaces of both alloys after incubation in simulated body fluid. Furthermore, the alloys were subjected to corrosion tests and in-vitro MTT cytotoxicity and alkaline phosphatase (ALP) assays. Optical micrographs revealed a more refined grain structure for M354 due to precipitation of Alx(Zr, Ti)Si and Al3Ni containing particles on the grain boundaries. FE-SEM /EDX analysis showed increased calcium content on M354 compared to the 354 alloy following incubation. AFM revealed a higher initial surface roughness for M354, which decreased after incubation, while the roughness of the 354 alloy increased, indicating M354’s strong bioactivity. M354 alloy exhibits a more positive potential than the non-modified 354 version, M354 likewise showed higher cell proliferation. Both alloys exhibited higher ALP activity than the control, indicating that the alloying elements had no adverse effects on cell biocompatibility.