TY - JOUR
T1 - Self-referenced assay method for photonic crystal biosensors
T2 - Application to small molecule analytes
AU - Chan, Leo L.
AU - Cunningham, Brian T.
AU - Li, Peter Y.
AU - Puff, Derek
N1 - Funding Information:
This material is based upon work supported by the National Science Foundation under Grant No. 0427657. Any opinions, findings, and conclusions or recommendations expressed in this material are those of the author(s) and do not necessarily reflect the views of the National Science Foundation. The authors gratefully acknowledge SRU Biosystems for providing financial support for this work. The authors also extend their gratitude to Xuan Li and the support staff of the University of Illinois Metabolomics Center for the use of Perkin-Elmer Piezoarray.
PY - 2007/1/10
Y1 - 2007/1/10
N2 - Using an image-based method for label-free detection of biochemical binding density distribution on the surface of a photonic crystal biosensor embedded within standard format multiwell microplates, a new method for automatic referencing of assay errors due to variability in the bulk refractive index of the analyte test sample is demonstrated. The new method involves application of the immobilized ligand upon the biosensor surface as a small spot, so that uncoated regions of a microplate well may serve as an accurate reference for the "active" regions containing the ligand. Due to the high spatial resolution of the image-based detection approach, each well in the microplate may be represented by hundreds of independent measurements of biochemical binding density, as measured by the shift in reflected wavelength from the photonic crystal biosensor. A linear plot of detected analyte density as a function of immobilized ligand density is constructed, in which the slope represents the ligand/analyte affinity and the intercept represents common-mode error effects. Streptavidin-biotin is used as a ligand-analyte model system to demonstrate the ability of this method to separate intentionally introduced bulk refractive index errors from the detection of a small molecule analyte. This referencing approach will be important in the context of small molecule drug compound library screening, where drug compounds within a large library are often suspended in solutions of inconsistent bulk refractive index.
AB - Using an image-based method for label-free detection of biochemical binding density distribution on the surface of a photonic crystal biosensor embedded within standard format multiwell microplates, a new method for automatic referencing of assay errors due to variability in the bulk refractive index of the analyte test sample is demonstrated. The new method involves application of the immobilized ligand upon the biosensor surface as a small spot, so that uncoated regions of a microplate well may serve as an accurate reference for the "active" regions containing the ligand. Due to the high spatial resolution of the image-based detection approach, each well in the microplate may be represented by hundreds of independent measurements of biochemical binding density, as measured by the shift in reflected wavelength from the photonic crystal biosensor. A linear plot of detected analyte density as a function of immobilized ligand density is constructed, in which the slope represents the ligand/analyte affinity and the intercept represents common-mode error effects. Streptavidin-biotin is used as a ligand-analyte model system to demonstrate the ability of this method to separate intentionally introduced bulk refractive index errors from the detection of a small molecule analyte. This referencing approach will be important in the context of small molecule drug compound library screening, where drug compounds within a large library are often suspended in solutions of inconsistent bulk refractive index.
KW - Label-free detection
KW - Optical biosensor
KW - Photonic crystal
KW - Small molecule
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U2 - 10.1016/j.snb.2006.02.047
DO - 10.1016/j.snb.2006.02.047
M3 - Article
AN - SCOPUS:33845651698
VL - 120
SP - 392
EP - 398
JO - Sensors and Actuators B: Chemical
JF - Sensors and Actuators B: Chemical
SN - 0925-4005
IS - 2
ER -