The cleaning of protein-contaminated metallic surfaces is a major challenge for non-disposable devices used for biomedical applications and in the food industry. The objective of this work is to estimate the cleaning efficiency of sodium dodecyl sulfate (SDS) buffered at pH 7.4, as a function of temperature, for an immersion time of 15 h. Bovine serum albumin (BSA) is preadsorbed on pure Ti-and Cr-deposited quartz crystals. BSA adsorption and removal were investigated by X-ray photoelectron spectroscopy (XPS) and quartz crystal microbalance (QCM). Before cleaning, the amount of adsorbed BSA corresponds to one monolayer, and the oxide thickness is about 5 nm for the Cr quartz (Cr 3+ in oxide and hydroxide). For Ti quartz, the metal is not detected (10 nm or more of Ti 4+ in TiO 2 ). The C 1s and N 1s peaks indicate that the cleaning with SDS is achieved at 37• C for Ti. For Cr, there are no significant changes from 37 to 60• C. At 80 • C, the surface is partially cleaned (70% efficiency); at 90 • C, the surface cleaning with SDS is achieved (90% efficiency). The oxide layer of the chromium sample has not changed in composition and thickness.QCM measurements were performed at 37 • C. Switches between BSA and SDS solutions indicate that for Ti, SDS induces partial BSA removal (40% efficiency) after ∼20 min, while for Cr it seems that SDS adsorbs reversibly on the BSA layer, without any cleaning effect. Thus, QCM results are in agreement with XPS data obtained at the same temperature.

In this work, kinetics data on adsorption of fibronectin (Fn) on passivated Ti surfaces (Ti quartz crystals) in phosphate buffered saline (PBS) solution were obtained from in situ investigations with electrochemical quartz crystal microbalance (EQCM): from experiments performed at 15 and 60 mg l −1 Fn solution concentrations, the maximum adsorption was reached within 30 min, and Fn adsorption seemed to be partially reversible, as about 15% of the initially adsorbed protein were removed upon PBS rinsing. The remaining amount of adsorbed Fn was around 1000 ng cm −2 and was similar for both protein concentrations in solution. Moreover, differences in kinetics were observed between the two concentrations: the initial adsorption rate was much larger at 60 mg l −1 than at 15 mg l −1 . Ex situ X-ray photoelectron spectroscopy (