TiO2NT as Platform for Drug Release: The Effect of Film Wettability

Modifications of Ti-based surface are increasingly studied to improve biological responses on the biomedical implants field. In this study, nanotubular arrays were grown from Ti-cp (T) and its alloy, Ti6Al4V (A), by potentiostatic anodization at 25 V for 90 min in ethylene glycol media containing 0.75 % w/w of NH4F, H2O 9% v/v and 1% v/v of Simulated Body Fluid (SBF) maintained at 10 degrees C (T10 and A10) and 40 degrees C (T40 and A40) for drug release studies. Coatings were top filled with cefazolin (1 mg) and the releasing procedure was performed in 5 mL of PBS at 37 degrees C, taking 0.5 mL aliquots at 1, 4, 7, 10, 15 and 30 min. The as-formed coatings were characterized by Scanning Electron Microscopy (SEM), X-rays Diffraction (XRD) and contact angle measurements. Contact angle measurements indicate that T-based nanotubular coatings are highly wettable, being approximate to 0.00 degrees and 6.74 degrees +/- 1.96 for T10 and T40 respectively. Coatings obtained from Ti-alloy exhibits low wettability than T-based samples for both temperatures. All samples release the drug on short time intervals (4 to 10 min). The drug release rate is inversely proportional to the contact angle, considering substrate groups. Thus, a higher wettability tendency presents a higher release rate. This result shows that wettability is an important parameter to be considered in the design of Ti-based biomaterials.