AVS 49th International Symposium
    Biomaterials Thursday Sessions
       Session BI+HS+SS-ThM

Paper BI+HS+SS-ThM6
Evaluation of Methodologies for Arraying a Porous Inorganic Bioassay Support@footnote 1@

Thursday, November 7, 2002, 10:00 am, Room C-201

Session: Biosensors and Biodiagnostics
Presenter: C. Cole, Nova Research, Inc.
Authors: C. Cole, Nova Research, Inc.
D.B. Chrisey, Naval Research Laboratory
R.J. Colton, Naval Research Laboratory
H. Kim, Naval Research Laboratory
B.R. Ringeisen, Naval Research Laboratory
C.R. Tamanaha, Geo-Centers, Inc.
L.J. Whitman, Naval Research Laboratory
Correspondent: Click to Email
A membrane-based immunosensor has been developed for the detection of eight biological agents with a response time of <15 minutes and a sensitivity ~3 orders of magnitude higher than conventional ELISAs. The Force Discrimination Biosensor@footnote 2@ (FDB) uses generically functionalized 0.8 µm-diameter beads to label captured target; a magnetic field gradient removes nonspecifically bound beads, thus improving sensitivity by reducing both background and the incident of false positives. Already demonstrated for single analyte detection, methodologies to array the alumina ultrafiltration membrane for multiplexed detection have been evaluated. One of the biggest challenges is to array hydrophobic antibody conjugates onto porous hydrophilic PEG-biotin surfaces without losing pattern integrity due to lateral wicking. Patterning via a PDMS stamp or mask works reasonably well, but is too cumbersome for the patterning of the large number of membranes needed for practical applications. Instead, a pulsed laser transfer technique developed at NRL has been adapted to pattern antibody conjugates@footnote 3@ onto PEGylated membranes. With an average element dimension of (100 µm)@super 2@ and 200 µm spacing between elements, a 10 x 10 array can be written in 3 mm@super 2@. Such arrays can be patterned to give a single diagnostic for a variety of bacterial, viral, or protein agents without requiring the use of an additional membrane for positive/negative controls. Multiplexed assays for bacterial spores and cells, viruses, and protein toxins have been performed with these filters; results will be presented to demonstrate the application of pulsed laser writing to biosensor patterning. @FootnoteText@ @footnote 1@ Supported by the Joint Service Technical Panel for Chemical and Biological Defense.@footnote 2@ Lee et al., Anal. Biochem. 287, 261 (2000).@footnote 3@ Ringeisen et al., Biomaterials 23, 161 (2002).