title: Bifunctional 4MBA mediated recyclable SERS-based immunoassay induced by photocatalytic activity of TiO2 nanotube arrays.
abstract: We first report here a novel recyclable surface-enhanced Raman scattering (SERS)-based immunoassay via the photocatalytic ability of anatase titania nanotube (TiO2-NT) arrays. In this immunoassay, an immune probe was realized by immobilizing anti-CA19-9 onto Ag@SiO2@Ag three core-shell nanoparticles (TCSNPs), which showed a much higher SERS activity than bare Ag NPs with an enhancement ratio of 1.75. Then, the vertically oriented TiO2-NT immune substrate was synthesized by ultra-fast anodic oxidation of flexible titanium foils and functionalised with 4-mercaptobenzoic acid (4MBA) molecules to link them with anti-CA19-9. The immunoassay using the above immune probe and the substrate exhibited a wide linear range from 1000 to 0.5 U mL(-1) and a low detection limit of 0.5 U mL(-1) for CA19-9 due to the excellent SERS performance of Ag@SiO2@Ag TCSNPs. More importantly, the linkage between TiO2-NTs and 4MBA was destroyed by catalyzing 4MBA into 4-sulfobenzoate upon UV irradiation in O2-saturated water. The target antigen and the immune probe were simultaneously removed leading to a recyclable immunoassay and a detection limit of 5 U mL(-1) was achieved after six cycles. The simplicity and versatility of this strategy may bridge the technology gap between academia and practical detection, which makes it promising for clinical SERS-based immunoassay.
authors: Institute of Photonics, Faculty of Science, Ningbo University, Ningbo, 315211, Zhejiang, China. jiangtao@nbu.edu.cn zhoujun@nbu.edu.cn.
authors: Xiaolong
authors: X
authors: Wang
authors: Lu
authors: L
authors: Zhou
authors: Wei
authors: W
authors: Lai
authors: Tao
authors: T
authors: Jiang
authors: Jun
authors: J
authors: Zhou
mesh_terms: D000906:Antibodies / Q000737:chemistry / Q000276:immunology; D001565:Benzoates / Q000737:chemistry*; D018395:CA-19-9 Antigen / Q000032:analysis* / Q000276:immunology; D002384:Catalysis; D007118:Immunoassay / Q000379:methods*; D057230:Limit of Detection; D008855:Microscopy, Electron, Scanning; D053758:Nanoparticles / Q000737:chemistry; D043942:Nanotubes / Q000737:chemistry*; D010084:Oxidation-Reduction / Q000528:radiation effects; D012822:Silicon Dioxide / Q000737:chemistry; D012834:Silver / Q000737:chemistry; D013059:Spectrum Analysis, Raman; D013438:Sulfhydryl Compounds / Q000737:chemistry*; D013499:Surface Properties; D014025:Titanium / Q000737:chemistry*; D014466:Ultraviolet Rays; D014867:Water / Q000737:chemistry
chemical_list: D000906:Antibodies; D001565:Benzoates; D018395:CA-19-9 Antigen; D013438:Sulfhydryl Compounds; D014867:Water; C013594:4-mercaptobenzoate; C009495:titanium dioxide; D012834:Silver; D012822:Silicon Dioxide; D014025:Titanium