Kairos-scientific Inc.

Christopher M Silva

Edward J Bylina

William Joseph Coleman

Mary M Yang

Michael Robert Dilworth

Douglas C Youvan

Steven J Robles

Dougalas C Youvan

Michael A Tanner

The present invention provides an instrument and methods for a multispectral optical technique that can simultaneously classify individual biological cells within mixed populations. This invention, known as Multispectral Taxonomic Identification (MTID), shows that microscopy can be combined with a software analysis program to measure and categorize the fluorescence and other spectroscopically identifiable signals from complex populations of cells in situ, without cultivation. The invention thus enables high-throughput screening of cells for taxonomic classification.

Multispectral taxonomic identification

Imaging hardware, software, calibrants, and methods are provided to visualize and quantitate the amount of Fluorescence Resonance Energy Transfer (FRET) occurring between donor and acceptor molecules in epifluorescence microscopy. The MicroFRET system compensates for overlap among donor, acceptor, and FRET spectra using well characterized fluorescent beads as standards in conjunction with radiometrically calibrated image processing techniques. The MicroFRET system also provides precisely machined epifluorescence cubes to maintain proper image registration as the sample is illuminated at the donor and acceptor excitation wavelengths. Algorithms are described that pseudocolor the image to display pixels exhibiting radiometrically-corrected fluorescence emission from the donor (blue), the acceptor (green) and FRET (red). The method is demonstrated on samples exhibiting FRET between genetically engineered derivatives of the Green Fluorescent Protein (GFP) bound to the surface of Ni chelating beads by histidine-tags.

Calibration of fluorescence resonance energy transfer in microscopy

A MicroColonyImager instrument and solid phase methods to screen cells expressing mutagenized enzymes for enhanced activity. The MicroColonyImager instrument and methods permit high throughput screening of enzyme libraries by time course analyses of single-pixels, using either absorption, fluorescence or FRET. This high throughput assay can detect small differences in enzyme rates within microcolonies grown at a nearly confluent density on an assay disk. Each microcolony is analyzed simultaneously at single-pixel resolution, requiring less than 100 ml substrate/measurement. By simultaneously assaying different substrates tagged with spectrally distinct chromogenic or fluorogenic reporters, the substrate specificity of an enzyme can be changed.

Solid phase enzyme kinetics screening in microcolonies

Growing community of inventors

Sunnyvale, CA, United States of America

Christopher M Silva