51 results about "Fluorescence-Activated Cell Sorting" patented technology

In certain embodiments this invention provides a pulsed-laser triggered microfluidic switching mechanism that can achieve a switching time of 70 μs. This switching speed is two orders of magnitude shorter than that of the fastest switching mechanism utilized in previous μFACS.

The present invention provides a genetic method for tethering polypeptides to the yeast cell wall in a form accessible for binding to macromolecules. Combining this method with fluorescence-activated cell sorting provides a means of selecting proteins with increased or decreased affinity for another molecule, altered specificity, or conditional binding. Also provided is a method for genetic fusion of the N terminus of a polypeptide of interest to the C-terminus of the yeast Aga2p cell wall protein. The outer wall of each yeast cell can display approximately 10 protein agglutinins. The native agglutinins serve as specific adhesion contacts to fuse yeast cells of opposite mating type during mating. In effect, yeast has evolved a platform for protein-protein binding without steric hindrance from cell wall components.

A method is provided for the isolation of endothelial progenitor cells from a source of progenitor cells by isolating a population of lineage-negative cells and further isolating CD34+ cells from the lineage-negative population by fluorescence-activated cell sorting. Isolated populations of endothelial progenitor cells and therapeutic compositions containing CD34+ cells for the induction of blood vessels, induction of angiogenic responses in surrounding blood vessels and the chemotaxis of inflammatory cells are also provided.

The invention discloses a method for analyzing epitope of monoclonal antibody by using a yeast surface display system and application of the method in vaccine development. The method comprises the following steps of: (1) constructing a DNA library of target protein; (2) displaying the DNA library on the surface of yeast to obtain a yeast display library; (3) mixing the monoclonal antibody of the target protein and a yeast display library A, and screening yeast combined with the monoclonal antibody; and (4) extracting plasmid of the screened yeast, sequencing, and analyzing the epitope of the target protein. Compared with the traditional method, the method has the advantages that: (1) ways of modifying the protein by yeast cells on are more, and high molecular weight and complicated protein can be displayed; (2) the yeast can be screened one by one by fluorescence-activated cell sorting (FACS), and the accuracy and screening flux are improved; (3) the yeast can independently complete self growing and reproducing process, the operation is simple and convenient and interference factors are a few; and (4) the yeast is an immunologic adjuvant, and can check whether the epitope can induce the generation of antibody with similar activity again.

A digital store comprising of a method to store digital data in live micro-organisms, and a method to selectively retrieve subsets of stored data, is disclosed. Digital data is represented as a plurality of key-value pairs. The proposed system stores copies of key-value pairs in a plurality of live micro-organisms. Upon presentation of a retrieval key, the proposed digital store retrieves the value associated with the retrieval key. Storage method for a key-value pair comprises of (a) mapping the key to a gene that expresses a unique fluorescent protein so that no two keys map to the same gene, (b) encoding the key-value pair as base-pair sequences, (c) synthesizing oligonucleotide chains from base-pairs for the key-value pair and the gene, (d) synthesizing recombinant DNA plasmids that have oligonucleotide chains for the key-value pair, the gene, and two primers, as foreign DNA inserts, (e) incorporation of recombinant DNA plasmids into live micro-organisms, (f) isolation of live micro-organisms that have absorbed the recombinant DNA plasmids, and (g) safe storage of population of live micro-organisms with embedded key-value pairs in a common pool. Retrieval of the value paired with a key comprises of (a) taking as input the retrieval key, and mapping the key to the specific gene for fluorescent protein, (b) taking a sample from the safe storage pool that contains live micro-organisms embedded with key-value pairs, (c) isolating the live micro-organisms that have expressed the gene by using high-speed fluorescence activated cell sorting or flow cytometry, (d) extracting DNA from the recombinant DNA plasmid in the isolated live micro-organisms, (d) selectively amplifying and sequencing only those DNA strands that contain the value for the key, and (e) decoding the base-pair sequence obtained after DNA sequencing to yield the value associated with the retrieval key.We also disclose two important variations. The first variation relates to the storage step. The recombinant DNA plasmid is constructed to include additional non-fluorescent oligonucleotides and genes so that during the data retrieval step, the live micro-organisms that have absorbed the said plasmid can be sorted by cell sorters based on parameters of individual cells such as cell size, cell complexity, cell phenotype, cell structure, cell function, and magnetic or electrical properties. The second variation relates to both storage and retrieval of key-value pairs with large values. To store such a key-value pair, the large value is split into smaller blocks so that a block can fit into a recombinant DNA plasmid, and a distinct pair of primers is used for each block. A block's primer pair is used to selectively amplify and sequence only the DNA that encodes the data in the block, thereby enabling the retrieval of a specific block of the value, as opposed to retrieving the entire value associated with a key.

The invention belongs to the field of enzyme engineering and discloses a carboxyl coumarin based phosphotriesterase fluorogenic substrate and a substrate based high-flux screening method for phosphotriesterase. The method is an in vitro compartmentalization based fluorescence-activated cell sorting ultrahigh-flux screening technology for phosphotriesterase. According to the method, a reacted fluorescent product of the carboxyl coumarin based phosphotriesterase substrate has a very good droplet retention property and has the advantages of high sensitivity and accuracy in quantification in the quantifying and screening of enzymatic activity. Due to the hydrophilic difference between the substrate and a reaction product, the substrate can be added into an external water phase and seep through an oil phase for enzymatic reaction; and the produced product is retained in liquid droplets due to improved hydrophilicity, so that the effect of liquid droplet fluorescence capture is achieved, the reaction time is accurately controlled, the fluorescent background interference is lowered, and the accuracy of screening is improved.