title: In situ study of self-assembled nanocomposite films by spectral SPR sensor.
abstract: Spectral surface plasmon resonance (SPR) sensor with a time-resolved charge-coupled device (CCD) detector is a powerful analytical tool for label-free detection of biomolecular interaction at the liquid/solid interface and for in situ study of molecular adsorption behavior. In this work, the layer-by-layer self-assembly processes for three nanocomposite films were monitored in real time using a broadband spectral SPR sensor with a large dynamic range. Kinetics studies suggest that cytochrome c (Cyt c) and deoxy ribonucleic acid (DNA) adsorptions obey the Langmuir-isotherm theory, while gold nanoparticle (GNP) adsorption follows the Diffusion-controlled model. Using poly(sodium 4-styrenesulfonate) (PSS) and poly(dimethyldiallylammonium chloride) (PDDA) as the positively charged agents, three kinds of multilayer films such as the PSS/Cyt c, GNP/Cyt c and PDDA/DNA binary nanocomposites were fabricated on the SPR chips by the electrostatic attraction based on self-assemble. The SPR response in terms of ΔλR was measured to linear increase with increasing the number of layers for a six-bilayer PSS/Cyt c nanocomposite film, indicating that every PSS/Cyt c layer has equal mass coverage. In contrast, the nonlinear dependences of ΔλR on the number of bilayers were observed for the GNP/Cyt c and PDDA/DNA nanocomposite multilayer films.
authors.affiliation: Department of Biomedical Engineering, School of Computer and Information Technology, Beijing Jiaotong University, Beijing 100044, China.
authors.forename: Zhe
authors.initials: Z
authors.lastname: Zhang
authors.affiliation: Department of Biomedical Engineering, School of Computer and Information Technology, Beijing Jiaotong University, Beijing 100044, China. Electronic address: jieliu@bjtu.edu.cn.
authors.forename: Jie
authors.initials: J
authors.lastname: Liu
authors.affiliation: State Key Laboratory of Transducer Technology, Institute of Electronics, Chinese Academy of Sciences, Beijing 100190, China.
authors.forename: Zhi-mei
authors.initials: ZM
authors.lastname: Qi
authors.affiliation: State Key Laboratory of Transducer Technology, Institute of Electronics, Chinese Academy of Sciences, Beijing 100190, China.
authors.forename: Dan-feng
authors.initials: DF
authors.lastname: Lu
mesh_terms: D000327:Adsorption; D001704:Biopolymers / Q000032:analysis* / Q000737:chemistry; D004867:Equipment Design; D019544:Equipment Failure Analysis; D008422:Materials Testing / Q000295:instrumentation*; D008567:Membranes, Artificial; D053761:Nanocomposites / Q000032:analysis / Q000737:chemistry*; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D013057:Spectrum Analysis / Q000295:instrumentation; D020349:Surface Plasmon Resonance / Q000295:instrumentation*
chemical_list: D001704:Biopolymers; D008567:Membranes, Artificial
keywords: Adsorption; Kinetics; Layer-by-layer self-assembly; Wavelength-interrogated SPR