title: A stable, label-free optical interferometric biosensor based on TiO2 nanotube arrays.
abstract: Optical interferometry of a thin film array of titanium dioxide (TiO2) nanotubes allows the label-free sensing of rabbit immunoglobulin G (IgG). A protein A capture probe is used, which is immobilized on the inner pore walls of the nanotubes by electrostatic adsorption. Control experiments using IgG from chicken (which does not bind to protein A) confirms the specificity of the protein A-modified TiO2 nanotube array sensor. The aqueous stability of the TiO2 nanotube array was examined and compared with porous silica (SiO2), a more extensively studied thin film optical biosensor. The TiO2 nanotube array is stable in the pH range 2 to 12, whereas the porous SiO2 sensor displays significant degradation at pH > 8.
authors.affiliation: Department of Metal and Materials Engineering, Kangnung National University 120, Kangnung Daehangno, Kangnung 210-702, Korea.
authors.forename: Kyu-Shik
authors.initials: KS
authors.lastname: Mun
authors.forename: Sara D
authors.initials: SD
authors.lastname: Alvarez
authors.forename: Won-Youl
authors.initials: WY
authors.lastname: Choi
authors.forename: Michael J
authors.initials: MJ
authors.lastname: Sailor
mesh_terms: D000327:Adsorption; D000818:Animals; D015374:Biosensing Techniques / Q000379:methods*; D007074:Immunoglobulin G / Q000032:analysis / Q000737:chemistry / Q000276:immunology; D007368:Interferometry / Q000379:methods*; D008027:Light; D008855:Microscopy, Electron, Scanning; D043942:Nanotubes / Q000737:chemistry*; D011817:Rabbits; D017550:Spectroscopy, Fourier Transform Infrared; D013205:Staphylococcal Protein A / Q000032:analysis / Q000737:chemistry / Q000276:immunology; D014025:Titanium / Q000737:chemistry*
chemical_list: D007074:Immunoglobulin G; D013205:Staphylococcal Protein A; C009495:titanium dioxide; D014025:Titanium