title: Area-scaling of interferometric and fluorescent detection of protein on antibody microarrays.
abstract: The sensitivity limits for an in-line interferometric (IL)/fluorescent (FL) dual-channel BioCD are established as a function of spatial averaging. Forward-phase and sandwich assays at 10ng/ml were performed on large-scale antibody microarrays (6800-spot) and detected using in-line interferometry and fluorescence channels. The interferometric channel has an extrapolated label-free limit-of-detection (LOD) of 250pg/ml in a forward-phase assay for which the fluorescent channel is inapplicable. In the sandwich assay, the extrapolated limit-of-detection is 70pg/ml for the interferometric channel, and for the fluorescent channel it is 30pg/ml. Intrinsic scale-free sensitivities for the detection channels are defined assuming spatially uncorrelated fluctuations with sensitivities of S'=13pg/mm for interferometric detection and 7pg/mm for sandwich fluorescent detection. The intrinsic sensitivities become weakly scale dependent in the presence of fractal spatial correlations among the antibody spots.
authors.affiliation: Department of Physics, 525 Northwestern Avenue, West Lafayette, IN 47907-2036, USA.
authors.forename: Xuefeng
authors.initials: X
authors.lastname: Wang
authors.forename: Ming
authors.initials: M
authors.lastname: Zhao
authors.forename: David D
authors.initials: DD
authors.lastname: Nolte
mesh_terms: D015374:Biosensing Techniques / Q000295:instrumentation* / Q000379:methods; D003198:Computer Simulation; D017076:Computer-Aided Design; D004867:Equipment Design; D019544:Equipment Failure Analysis; D007118:Immunoassay / Q000295:instrumentation* / Q000379:methods; D007368:Interferometry / Q000295:instrumentation* / Q000379:methods; D008956:Models, Chemical; D040081:Protein Array Analysis / Q000295:instrumentation* / Q000379:methods; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D013050:Spectrometry, Fluorescence / Q000295:instrumentation* / Q000379:methods