Grating-based sensor combining label-free binding detection and fluorescence amplification and readout system for sensor

Abstract

A grating-based sensor is disclosed that has a grating structure constructed and designed for both evanescent resonance (ER) fluorescence detection and label-free detection applications. One and two-dimensional gratings are also disclosed, including gratings characterized by unit cells with central posts, central holes, and two-level, two-dimensional gratings. A readout system for such sensors is also disclosed. Various applications for the biosensors are described, including cell-based assays for assessing the effect of drug compounds on cell function. A biosensor embodiment optimized for a luminescent response at two different wavelengths is also described. Such luminescent response could be produced by fluorescence (either native or from an attached fluorophore), phosphorescence, chemi-luminescence, or other luminescence technology. Two different luminescence technologies could be combined on the same biosensor chip.

1 . A grating-based biosensor comprising a substrate having a periodic surface grating structure wherein the periodic grating structure is constructed in a manner designed for optical interrogation of the sensor with excitation light at least two discrete wavelengths in an evanescent resonance (ER) detection mode to thereby produce a luminescence response from a sample, placed on the biosensor at least two discrete emission wavelengths. 
   
   
       2 . The biosensor of  claim 1 , wherein the luminescence response comprises a fluorescence response, such fluorescence being either native fluorescence or fluorescence produced by a fluorescent material attached to the sample. 
   
   
       3 . The biosensor of  claim 1 , wherein the luminescence response comprises a phosphorescent response. 
   
   
       4 . The biosensor response of  claim 2 , wherein the fluorescence response is produced by a dye which is bound to a sample placed on the biosensor. 
   
   
       5 . The biosensor of  claim 1 , wherein a first emission wavelength is in the near infrared portion of the spectrum and wherein a second emission wavelength is in the visible portion of the spectrum. 
   
   
       6 . The biosensor of  claim 1 , wherein a first emission wavelength corresponds to the emission wavelength of a first dye associated with a sample placed on the biosensor and wherein a second emission wavelength corresponds to the emission wavelength of a second dye associated with the sample. 
   
   
       7 . The biosensor of  claim 6 , wherein the first dye comprises Cyanine-5 and the second dye comprises Cyanine-3. 
   
   
       8 . The biosensor of  claim 6 , wherein the grating structure comprises a two-dimensional periodic grating structure, the periodic grating structure is periodic in first and second dimensions, and wherein the first and second dimensions are mutually orthogonal, and wherein the periodic grating structure in the first dimension is optimized for optical interrogation of the biosensor to produce fluorescence from a first dye and wherein the periodic grating structure in the second dimension is optimized for optical interrogation of the biosensor to produce fluorescence from a second dye, the first and second dies emitting fluorescence at different wavelengths. 
   
   
       9 . A grating-based biosensor comprising a substrate having a periodic surface grating structure wherein the periodic grating structure is constructed in a manner designed for optical interrogation of the sensor with light in an evanescent resonance (ER) detection mode to produce a luminescence response from a sample placed on the biosensor at two discrete wavelengths, and wherein the luminescence response at the two discrete wavelengths is produced from two different types of luminescence. 
   
   
       10 . The biosensor of  claim 9 , wherein one of the two types of luminescence comprises fluorescence; such fluorescence being either native fluorescence or fluorescence produced by a fluorescent material attached to the sample. 
   
   
       11 . The biosensor of  claim 9 , wherein one of the two types of luminescence comprises phosphorescence. 
   
   
       12 . The biosensor of  claim 9 , wherein one of the two types of luminescence comprises chemi-luminescence. 
   
   
       13 . The biosensor of  claim 9 , wherein one of the two types of luminescence comprises electro-luminescence. 
   
   
       14 . The biosensor of  claim 9 , wherein the luminescence response at least one of the two discrete wavelengths is produced by a dye which is bound to the sample. 
   
   
       15 . The biosensor of  claim 9 , wherein the grating structure comprises a two-dimensional periodic grating structure, the periodic grating structure is periodic in first and second dimensions, and wherein the first and second dimensions are mutually orthogonal.