Grade-1 titanium soaked in a DMEM solution at 37 °C

• DMEM solutions are usually used in performing the in vitro cell culture studies.
• Hepes-buffered, phenol red- and sodium pyruvate-free DMEM are used in this study.
• Grade-1 Ti coupons were soaked in the above DMEM solutions at 37 °C.
• DMEM solutions deposited X-ray-amorphous calcium phosphate; not hydroxyapatite.
• SBF solutions deposit hydroxyapatite of poor crystallinity (but not ACP) on Ti.

DMEM (Dulbecco's modified Eagle medium) solutions are used in performing in vitro cell culture experiments to assess the cell biocompatibility of synthetic biomaterials. In this study, Hepes-buffered, phenol red- and sodium pyruvate-free DMEM solutions were used, for the first time as immersion media at 37 °C, to test alkali-treated (5 M NaOH, 60 °C, 24 h) grade-1 titanium substrates. Such DMEM solutions were found to deposit X-ray-amorphous calcium phosphate (ACP), in one or two weeks, on the soaked grade-1 Ti substrates. A limited number of previous studies focusing on the biomimetic coating of alkali-treated Ti6Al4V coupons in DMEM have actually used different DMEM solutions, which were not Hepes-buffered and containing phenol red and sodium pyruvate. The previous studies with such DMEM solutions reported the deposition of cryptocrystalline apatitic calcium phosphate (Ap-CaP) on Ti6Al4V substrates, but not ACP. An inorganic solution (free of amino acids, vitamins, glucose, sodium pyruvate and phenol red), simulating the ion concentrations of the DMEM solutions, was also used for the first time in depositing ACP on grade-1 Ti substrates upon soaking at 37 °C for only 24 h. The solutions and deposits of this study were analyzed by AAS, ICP-AES, FTIR, XRD, XPS, and surface profilometry.