Facile synthesis of robust free-standing TiO2 nanotubular membranes for biofiltration applications

Abstract

Robust monodisperse nanoporous membranes have a wide range of biotechnological applications, but are often difficult or costly to fabricate. Here, a simple technique is reported to produce free-standing TiO2 nanotubular membranes with through-hole morphology. It consists in a 3-step anodization procedure carried out at room temperature on a Ti foil. The first anodization (1 h at 80 V) is used to pattern the surface of the metallic foil. Then, the second anodization (24 h at 80 V) produces the array of TiO2 nanotubes that will constitute the final membrane. A higher voltage anodization (3-5 minutes at 180 V) is finally applied to detach the TiO2 nanotubular layer from the underlying Ti foil. In order to completely remove the barrier layer that obstructs some pores of the membrane, the latter is etched 2 minutes in a buffered oxide etch solution. The overall process produces 60 μm-thick TiO2 nanotubular membranes with tube openings of 110 nm on one side and 73 nm on the other side. The through-hole morphology of these membranes has been verified by performing diffusion experiments with glucose, insulin and immunoglobulin G where in differences in diffusion rate are observed based on molecular weight. Such biocompatible TiO2 nanotubular membranes, with controlled pore size and morphology, have broad biotechnological and biomedical applications.

Electrocatalytic Performance of Titania Nanotube Arrays Coated with MoS2 by ALD toward the Hydrogen Evolution Reaction

“…The TNTAs were fabricated by titanium anodic anodization according to ref (39). The titanium foil was sonicated successively in acetone, ethanol, and water for 15 min, respectively, and then dried under N 2 flow.…”

Simulations and Analysis of Titanium Dioxide Nanotubes (Rutile (110) and Anatase (101))

“…The experimental and theoretical studies of nanotubes have increased over the past decade [1][2][3] . Nanostructured compounds containing Ti oxides are fairly investigated due to their electronic properties and the application possibilities in areas such as medicine 4,5 , molecular biology 6 , solar 7,8 , photocatalytic processes 9,10 . It is also the subject of study in the application as gas sensor [11][12][13] .…”

Influence of In Situ Oxide Dissolution on the Bottom Morphologies of Detached TiO2 Nanotube Films

“…Tube filling with nanoparticles [24,25] or nanorods [26,27] requires the efficient flow of solution into interior of NTs. Other newly 2 Journal of Nanomaterials exploited applications of TiO 2 NT membranes, for example, bioactive filters [28,29], ion exchange membranes [30], and through-hole photocatalysis [31,32], also require the use of membranes with open tube bottoms by fixing them to supporting frames.…”

“…A quick method to open the closed bottoms has been developed with the assistance of the reduced or elevated anodization voltages at the end of the anodization process [37][38][39]. However, the inner diameter of the opened pore is small and the membrane bottom has remnants-this requires an additional etching step to fully open the bottoms [29]. Another direct detachment of tube films at high voltages has no approach to control the objective film morphologies including tube diameter or film thickness [40].…”