Fabrication Of Gradient TiO₂ Nanotubes For High-throughput Screening Of Biological Responses

TiO2 nanotubes(TNTs)have received great attention owing to the size similarity to biomacromolecule,high surface area,loadable cavity,excellent biocompatibility and strong adhesion with substrate.To date,it remains controversial about the size effect of TNTs on the biological responses.And it is a big challenge to screen and evaluate the size effect of TNTs on biological responses from nemerous TNTs with different properties.Aim at above challenge,the main work includes:a)construct TNT gradients from HF electrolytes using bipolar electrochemistry;b)apply gradient TNTs for high-throughput evaluation of cell responses,protein adsorption and extend its applications;c)adjust the fabrication parameters of bipolar electrochemistry to obtain gradient TNTs with a wide range of diameters.The main progress includes:1.TNTs gradients with dimension of 30-100 nm were fabricated by bipolar electrochemistry from HF electrolyte.2.We show that the gradient TiO2 nanotubes can be used for high-throughput applications,including high-throughput screening of TNTs size effect on protein adsorption,platelet adhesion,bacterial adhesion and OCP deposition.3.We show that the gradient TiO2 nanotubes can be used for high-throughput screening of rat mesenchymal stem cell behaviors,including cell attachment,proliferation and differentiation.Results reveal that the size effect on short-term cell adhesion is not significant,but this size effect becomes prominent with time that cell proliferation and differentiation decreases with increasing nanotube size.Cell behavior can be comprehended by protein adsorption and the formation of focal adhesion.4.TNT gradients with large diameter range of 30-300 nm are fabricated by bipolar electrochemistry from organic electrolyte solution by controlling electrolyte composition,concentration and anodization time.The growth mechanism of the sample was preliminarily investigated.Meanwhile,these TNT gradients are further applied for high-throughput screening of rat mesenchymal stem cell adhesion and platelet adhesion.