Functionalized nanotubular oxide layer on Ti6Al4V as a regulator and biosensor of bone tissue remodeling

Purpose: Our aim was to obtain functionalized nanotubular oxide layer (TNTs) on Ti6Al4V alloy and evaluate its efficiency as a platform for electrochemical biosensor of bone remodeling markers. It was also crucial to examinate does the amount of bonded bALP and BMP-2 and antibodies depends from nanotubes diameter and their electrochemical properties. Design/methodology/approach: The antibody specific for bALP and BMP-2 were used to functionalize the TNTs on Ti6Al4V. The spectrophotometry and electrochemical measurements (CV and EIS) were used to examinate the functionalization efficiency and comfirmed sensing properties of the functionalized TNTs on Ti6Al4V alloy. Findings: The obtained results confirmed that TNTs can strongly bind antibodies by physioabsorption and may be a proper platform for biosensing of the selected markers. The protein immobilization efficiency depends over the nanotube diameter and their electrical charge. Thermally modified TNTs with 50 nm diameter on Ti6Al4V strongly bind bALP antibodies and bALP and it can be detected amperometrically. BMP-2 quantitatively binds to the functionalized non annealed charged TNTs with 100 nm diameter, and it is possible to detect it using EIS. Research limitations/implications: The biosensors presented in this work are simple and fast, but this construction is a prototype and need to be optimized to be used in bone remodelling diagnostics. Practical implications: Development of the functionalized TNTs on the Ti6Al4V sensitive for physiological concentrations of the bone remodelling markers may be alternative for immunotests in diagnostic of bone diseases. Moreover the TNTs morphology generates nano roughness over the Ti6Al4V surface and functionalized by antibodies strongly bind bALP or BMP-2 and stimulate bone proliferation. Originality/value: Unique value of this research is the statement the amount of bonded markers and antibodies depends from TNTs diameter and electrochemical properties, and that the prototype of novel biosensor electrode was developed.