Label-Free Assays on the BIND System

Abstract

Screening of biochemical interactions becomes simpler, less expensive, and more accurate when labels, such as fluorescent dyes, radioactive markers, and colorimetric reactions, are not required to quantify detected material. SRU Biosystems has developed a biosensor technology that is manufactured on continuous sheets of plastic film and incorporated into standard microplates and microarray slides to enable label-free assays to be performed with high throughput, high sensitivity, and low cost per assay. The biosensor incorporates a narrowband guided-mode resonance reflectance filter, in which the reflected color is modulated by the attachment/detachment of biochemical material to the surface. The technology offers 4 orders of linear dynamic range and uniformity within a plate, with a coefficient of variation of 2.5%. Using conventional biochemical immobilization surface chemistries, a wide range of assay applications are enabled. Small molecule screening, cell proliferation/ cytotoxicity, enzyme activity screening, protein-protein interaction, and cell membrane receptor expression are among the applications demonstrated. (Journal of Biomolecular Screening 2004:481-490)

Distributed feedback lasers based on perylenediimide dyes for label-free refractive index sensing

“…Over the past decades, different types of optical resonant refractive index sensors have been proposed. Most of them are based on passive optical structures such as gold films for surface plasmon resonance [2,3], photonic crystals [4][5][6][7], microrings [8], microsphere [9] and microtoroid [10] that interact with an external light source via reflection, transmission or waveguide coupling. Such sensors generally detect the resonant wavelength shift due to the interaction between the evanescent electric field of the resonant modes and the target analyte deposited on the sensor surface.…”

Photonic crystals for the application to spectrometers and wavelength filters

“…Illinois established fabrication process of multichannel PhC sensor plate on a plastic well which is commonly used in chemical/biological experiments. Typical reflection spectrum from each PhC region [45] and the picture of the plates [44] are shown in Fig. 4.…”

High-Throughput Affinity-Based Technologies for Small-Molecule Drug Discovery

“…8,9 Based upon data obtained by SPR, kinetic parameters and equilibrium constants of binding (i.e., on-rate, off-rate, and apparent dissociation constants) can be determined. 7,10,11 A recent study of carbonic anhydrase II that compared SPR with the traditional measurement of stopped-flow fluorescence showed that the kinetic parameters determined by SPR are in agreement with those determined by stopped-flow fluorescence.…”

“…8,9 Target protein is immobilized onto a solid surface via covalent or noncovalent interaction. Binding of small-molecule compounds changes the refractive index of the immobilized target, which can be detected by optical sensing.…”