title: Label-free detection of C-reactive protein using reflectometric interference spectroscopy-based sensing system.
abstract: Reflectometric interference spectroscopy (RIfS) is a label-free, time-resolved technique, and suitable for detecting antibody-antigen interaction. This work describes a continuous flow biosensor for C-reactive protein (CRP), involving an effective immobilization method of a monoclonal antibody against CRP (anti-CRP) to achieve highly sensitive RIfS-based detection of CRP. The silicon nitride-coated silicon chip (SiN chip) for the RIfS sensing was first treated with trimethylsilylchloride (TMS), followed by UV-light irradiation to in situ generation of homogeneous silanols on the surface. Following amination by 3-aminopropyltriethoxysilane, carboxymethyldextran (CMD) was grafted, and subsequently, protein A was immobilized to create the oriented anti-CRP surface. The immobilization process of protein A and anti-CRP was monitored with the RIfS system by consecutive injections of an amine coupling reagent, protein A and anti-CRP, respectively, to confirm the progress of each step in real time. The sensitivity was enhanced when all of the processes were adopted, suggesting that the oriented immobilization of anti-CRP via protein A that was coupled with the grafted CMD on the aminated surface of TMS-treated SiN chip. The feasibility of the present sensing system was demonstrated on the detection of CRP, where the silicon-based inexpensive chips and the simple optical setup were employed. It can be applied to other target molecules in various fields of life science as a substitute of surface plasmon resonance-based expensive sensors.
authors.affiliation: Graduate School of Engineering, Kobe University, Nada-ku, Kobe, Japan.
authors.forename: Hyung Woo
authors.initials: HW
authors.lastname: Choi
authors.forename: Yasuhiko
authors.initials: Y
authors.lastname: Sakata
authors.forename: Yoshikazu
authors.initials: Y
authors.lastname: Kurihara
authors.forename: Tooru
authors.initials: T
authors.lastname: Ooya
authors.forename: Toshifumi
authors.initials: T
authors.lastname: Takeuchi
mesh_terms: D000586:Amination; D000818:Animals; D055910:Antibodies, Immobilized / Q000737:chemistry* / Q000276:immunology; D015374:Biosensing Techniques / Q000295:instrumentation*; D002097:C-Reactive Protein / Q000032:analysis* / Q000276:immunology; D004867:Equipment Design; D006801:Humans; D055767:Immobilized Proteins / Q000737:chemistry; D040081:Protein Array Analysis / Q000295:instrumentation*; D012680:Sensitivity and Specificity; D012821:Silanes / Q000737:chemistry*; D013057:Spectrum Analysis / Q000295:instrumentation; D013205:Staphylococcal Protein A / Q000737:chemistry
chemical_list: D055910:Antibodies, Immobilized; D055767:Immobilized Proteins; D012821:Silanes; D013205:Staphylococcal Protein A; D002097:C-Reactive Protein