Cloning & Expression

Competent Cells & Transformation

Competent cells are ready to use bacterial cells that have been chemically treated to allow incorporation of foreign DNA/plasmids. Sigma-Aldrich has a variety of chemically competent and electrocompetent cells for transformation of DNA with the highest transformation efficiencies. Our GC5 and GC10 cloning strains enable blue/white selection, transformation of methylated DNA and are T1 phage resistant. Our BL21(DE3) expression strains allow for inducible gene expression when using T7 promoter driven expression systems.