title: A miniaturized germanium-doped silicon dioxide-based surface plasmon resonance waveguide sensor for immunoassay detection.
abstract: A surface plasmon resonance (SPR) waveguide immunosensor fabricated by germanium-doped silicon dioxide was investigated in this study. The designed waveguide sensor consisted of a 10 microm SiO(2) substrate layer (n=1.469), a 10 microm Ge-SiO(2) channel guide (n=1.492) and a 50 nm gold film layer for immobilization of biomolecules and SPR signal detection. The resultant spectral signal was measured by a portable spectrophotometer, where the sensor was aligned by a custom-designed micro-positioner. The results of the glycerol calibration standards showed that the resonance wavelength shifted from 628 to 758 nm due to changes of refractive index from 1.36 to 1.418. Flow-through immunoassay on waveguide sensors also showed the interactions of protein A, monoclonal antibody (mAb ALV-J) and avian leucosis virus (ALVs) resulted in wavelength shifting of 4.17, 3.03 and 2.18 nm, respectively. The SPR dynamic interaction could also be demonstrated successfully in 4 min as the sensor was integrated with a lateral flow nitrocellulose strip. These results suggest that SPR detection could be carried out on designed waveguide sensor, and the integration of nitrocellulose strip for sample filtering and fluid carrier would facilitate applications in point-of-care portable system.
authors.affiliation: Institute of Biomedical Engineering, National Taiwan University, Taipei, Taiwan.
authors.forename: Jhen-Gang
authors.initials: JG
authors.lastname: Huang
authors.forename: Chen-Lung
authors.initials: CL
authors.lastname: Lee
authors.forename: Hsueh-Min
authors.initials: HM
authors.lastname: Lin
authors.forename: Tsung-Liang
authors.initials: TL
authors.lastname: Chuang
authors.forename: Way-Seen
authors.initials: WS
authors.lastname: Wang
authors.forename: Rong-Huey
authors.initials: RH
authors.lastname: Juang
authors.forename: Ching-Ho
authors.initials: CH
authors.lastname: Wang
authors.forename: Chih Kung
authors.initials: CK
authors.lastname: Lee
authors.forename: Shi-Ming
authors.initials: SM
authors.lastname: Lin
authors.forename: Chii-Wann
authors.initials: CW
authors.lastname: Lin
mesh_terms: D015374:Biosensing Techniques / Q000295:instrumentation* / Q000379:methods; D003101:Collodion / Q000737:chemistry*; D004867:Equipment Design; D019544:Equipment Failure Analysis; D005336:Fiber Optic Technology / Q000295:instrumentation*; D005857:Germanium / Q000737:chemistry*; D007118:Immunoassay / Q000295:instrumentation* / Q000379:methods; D008904:Miniaturization; D012822:Silicon Dioxide / Q000737:chemistry*; D020349:Surface Plasmon Resonance / Q000295:instrumentation* / Q000379:methods; D013499:Surface Properties
chemical_list: D005857:Germanium; D012822:Silicon Dioxide; D003101:Collodion