The present invention generally relates to imaging cells, for example, to determine phenotypes and/or genotypes in populations of cells, e.g., to build genotype-phenotype corresponse for high-throughput screening. In some cases, the cells may be manipulated, e.g., using CRISPR or other techniques. In certain embodiments, nucleic acids may be introduced to the cell, e.g., using a lentivirus. The nucleic acids may contain a guide portion comprising a DNA or RNA recognition sequence, a reporter portion, and an identification portion comprising one or more read sequences. The guide portion may be used to alter the phenotype of the cells, e.g., using a sequence, e.g., an sgRNA sequence, that can be targeted using CRISPR or other techniques, and in some cases, the phenotype of the cells may be determined using various imaging approaches. The identification portion may be determined using MERFISH or other suitable techniques. In addition, in some cases, association or colocalization between determination of the reporter and the read sequences may substantially improve decoding accuracy, e.g., due to lowered misidentification of background signals. Other aspects are generally directed to compositions or devices for use in such methods, kits for use in such methods, or the like.

The present invention relates inter alia to expression vector production as well as application to the production of host cells for protein repertoire expression and high-throughput screening. The invention also relates to primers useful for PCR amplification of nucleotide sequences encoding human antibody variable domains.

Methods of making and monitoring metabolites in cells are provided.

Provided herein are methods of developing biomolecule variants (such as proteins, RNA, or DNA) with improved characteristics, for example by developing libraries of variants with alterations to one or more specific monomer locations and screening said libraries for characteristics of interest. These alterations can include deletion, substitution, and insertion, and variants may comprise one alteration or a combination of alterations. Said methods may include further iterative cycles of library construction and evaluation to develop, for example, a biomolecule variant with improved characteristics compared to a reference biomolecule. The methods can also provide information that may be used in the rational design of variants.

Provided herein are methods of developing biomolecule variants (such as proteins, RNA, or DNA) with improved characteristics, for example by developing libraries of variants with alterations to one or more specific monomer locations and screening said libraries for characteristics of interest. These alterations can include deletion, substitution, and insertion, and variants may comprise one alteration or a combination of alterations. Said methods may include further iterative cycles of library construction and evaluation to develop, for example, a biomolecule variant with improved characteristics compared to a reference biomolecule. The methods can also provide information that may be used in the rational design of variants.

The present invention provides novel microfluidic substrates and methods that are useful for performing biological, chemical and diagnostic assays. The substrates can include a plurality of electrically addressable, channel bearing fluidic modules integrally arranged such that a continuous channel is provided for flow of immiscible fluids.

The invention provides a genetically modified micro-organism for intracellular biosynthesis of a cellular metabolite, comprising a synthetic error correction system having a penalty gene, whose expression leads to arrested growth or cell death (e.g. a toxin gene) in combination with a survival gene, whose expression provides an antidote that restores cell viability and normal growth (e.g. a cognate antitoxin gene). Alternatively, the system has a survival gene, alone, whose expression is essential for growth (i.e. essential gene). The synthetic error correction system further comprises a biosensor, whose function is to induce expression of the survival gene which leads to cell growth, only, when the cell produces a pre-defined level of a given metabolite. The invention further encompasses: a method for producing the genetically modified micro-organism; a method for producing a cellular metabolite with the genetically modified micro-organism; and use of the genetically modified micro-organism for producing a cellular metabolite.

Provided herein is a high-throughput method for screening and identifying regulatory elements that provide selective expression in a particular cell type of interest. Also provided are nucleic acid compositions used in the high-throughput screening method.

Provided herein is a high-throughput method for screening and identifying regulatory elements that provide selective expression in a particular cell type of interest. Also provided are nucleic acid compositions used in the high-throughput screening method.

High-throughput methods for screening large populations of variant proteins are provided. The methods utilize large-scale arrays of microcapillaries, where each microcapillary comprises a solution containing a variant protein, an immobilized target molecule, and a reporter element. Immobilized target molecules may include any molecule of interest, including proteins, nucleic acids, carbohydrates, and other biomolecules. The association of a variant protein with a molecular target is assessed by measuring a signal from the reporter element. The contents of microcapillaries identified in the assays as containing variant proteins of interest can be isolated, and cells expressing the variant proteins of interest can be characterized. Also provided are systems for performing the disclosed screening methods.