Abstract
Additive manufacturing (AM) offers a unique control over microstructure, mechanical and chemical characteristics, providing new opportunities to tailor both bulk and surface properties for biomedical applications compared to conventional manufacturing methods. Additively manufactured titanium–copper (Ti–Cu) alloys are of particular interest for antibacterial metallic implants, as controlled Cu ion release can restrict bacterial activity while maintaining the favorable mechanical and corrosion properties of Ti-based materials. However, the electrochemical potential difference between the matrix and formed intermetallic compounds (e.g., Ti2Cu), which usually segregate at grain boundaries, can promote micro-galvanic effects. These potential differences can influence the corrosion behavior, surface chemistry, and metal release, especially under physiologically relevant conditions. Understanding how alloy composition and solution chemistry affect these processes over time is therefore essential. In this study, metal release and surface chemical characteristics of additively manufactured Ti–Cu alloys containing 3 and 11.5 wt.% Cu were investigated during prolonged immersion for up to 14 days in simulated body environments. Two test solutions were employed: phosphate-buffered saline (PBS) and PBS containing bovine serum albumin (BSA) and hydrogen peroxide (H₂O₂), representing chemical complexity and enabling assessment of time-dependent surface interactions with proteins and oxidative species. Metal release was quantified using inductively coupled plasma mass spectrometry (ICP-MS) to evaluate Ti and Cu dissolution behavior over time. Surface changes associated with time-dependent immersion and solution chemistry were characterized using X-ray photoelectron spectroscopy (XPS), Auger electron spectroscopy (AES), and scanning electron microscopy (SEM). The effect of alloy composition, immersion duration, and test environment on the metal release behavior and surface chemical composition is discussed. This research provides insights that will help develop and optimize AM methods for new biomedical alloys that cannot be fabricated by conventional methods.