Premium
Immunoassays in a porous silicon interferometric biosensor combined with sensitive signal processing
Author(s) -
TinsleyBown A.,
Smith R. G.,
Hayward S.,
Anderson M. H.,
Koker L.,
Green A.,
Torrens R.,
Wilkinson A.S.,
Perkins E. A.,
Squirrell D. J.,
Nicklin S.,
Hutchinson A.,
Simons A. J.,
Cox T. I.
Publication year - 2005
Publication title -
physica status solidi (a)
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.532
H-Index - 104
eISSN - 1862-6319
pISSN - 1862-6300
DOI - 10.1002/pssa.200461101
Subject(s) - detection limit , porous silicon , biosensor , horseradish peroxidase , monolayer , silicon , chemistry , layer (electronics) , porosity , chromatography , analytical chemistry (journal) , materials science , nanotechnology , organic chemistry , enzyme
Orthogonal subspace signal processing algorithms (OSPA) have been developed to extract the optical thickness of a porous silicon layer to within one part in 10 5 from its reflectivity spectrum. This is equivalent to a limit of detection (LOD) of ∼40 pm change in optical thickness for a 3 µm thick layer, or an LOD of 1/2000 of a monolayer coverage with antibodies, of molecular weight 160 k Daltons, within a layer with pores of 100 nm diameter. A large molecule {horseradish peroxidase (HRP), MWt 40 kDa} has been detected at a concentration of 1 µg/ml by measuring its direct binding to anti‐HRP antibodies immobilised within a porous silicon layer. A competitive assay has been demonstrated for the detection of a small molecule {2, 4, 6 trinitrotoluene (TNT), MWt 227 Da} at 10 µg/ml. The projected LODs for HRP and TNT by these assays are 50 ng/ml and 1 µg/ml respectively. (© 2005 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)