A complete collection of single-use and high-throughput electrocompetent and chemically competent E. coli

Choosing the ideal competent cells for your cloning applications and workflows is critical for the success of your experiment. Considerations when selecting competent cells for cloning include:

  • Transformation method—chemical versus electroporation
  • Downstream application—cloning unstable inserts, protein expression, library construction, or general cloning


Benefits of buying competent cells

At Thermo Fisher Scientific, we have developed and improved proprietary methods to produce competent cells that consistently provide high transformation results. Our comprehensive range of standard and specialized strains have been engineered to help optimize your downstream experiments and streamline your cloning workflow.

The benefits of commercially manufactured cells include robust quality control to maintain high efficiency transformation, batch-to-batch consistency, and time savings. Our off-the-shelf competent cells are available in convenient formats suitable for high- and low-throughput cloning.

Competent cells by type

Choose competent cells based on transformation method.


Competent cells by application

Scientist observing petri dish with white and blue colonies

Thermo Fisher Scientific offers many E. coli strains as competent cells to streamline your workflow. Determine which competent cell strain fits your needs. Tables 1, 2, and 3 provide comprehensive lists of strains suitable for various cloning applications. You can choose from several formats to serve low- or high-throughput cloning workflows.

Learn about six considerations for choosing competent cells
Download selection guide

Routine cloning and subcloning

Table 1. Strains for routine cloning and subcloning

ApplicationE. coli strainEfficiency
SubcloningDH5α>1 x 106 cfu/µg
Routine cloningDH5α family*>1 x 108 cfu/µg
DH10B family*>1 x 109 cfu/µg
TOP10 family*>1 x 109 cfu/µg
For fast routine cloning
Mach1 T1R*>1 x 109 cfu/µg

* Available in a high-throughput configuration

View more chemically competent and high transformation efficiency cells that do not require an electroporator

Specialized cloning applications

Table 2. Strains for specialty cloning applications

ApplicationE. coli strainEfficiency
Cloning unstable DNAStbl2> 1 x 109 cfu/µg
Stbl3*> 1 x 108 cfu/µg
Stbl4> 5 x 109 cfu/µg
Bacmid creationDH10Bac> 1 x 108 cfu/µg
High efficiency cloning/cDNA or genomic library constructionMegaX DH10B T1R> 3 x 1010 cfu/µg

DH5α-E

> 1 x 1010 cfu/µg
OmniMax 2 T1R

> 5 x 109 cfu/µg

Stbl4> 5 x 109 cfu/µg
DH10B family
> 1 x 1010 cfu/µg
Propagating unmethylated DNAINV110> 1 x 106 cfu/µg
Cre-lox recombination PIR1
> 1 x 109 cfu/µg
PIR2
> 1 x 108 cfu/µg
Preparing single stranded DNA (ssDNA)TOP10F´ > 1 x 109 cfu/µg
TOP10F´

> 5 x 109 cfu/µg

DH12S> 1 x 1010 cfu/µg
DH5αF´IQ> 1 x 108 cfu/µg
INVαF'
> 1 x 108 cfu/µg
Maintaining supF-containing vectorsTOP10/P3> 1 x 109 cfu/µg
MC1061/P3> 1 x 108 cfu/µg
Propagating Gateway vectors and plasmids with ccdB geneccdB Survival 2 T1R> 1 x 109 cfu/µg

*Available in a high-throughput configuration 
⚡= Electrocompetent cells

Strains for protein expression

Table 3. Strains for protein expression

ApplicationE. coli strainEfficiency
High level protein expressionBL21 (DE3)>1 x 108 cfu/µg
BL21 Star (DE3)*>1 x 108 cfu/µg
Toxic protein expressionBL21-AI>1 x 108 cfu/µg
Improved expression regulationBL21(DE3)pLysS>1 x 108 cfu/µg
BL21(DE3)pLysE>1 x 107 cfu/µg
BL21 Star (DE3)pLysS>1 x 108 cfu/µg

* Available in a high-throughput configuration

Routine cloning and subcloning

Table 1. Strains for routine cloning and subcloning

ApplicationE. coli strainEfficiency
SubcloningDH5α>1 x 106 cfu/µg
Routine cloningDH5α family*>1 x 108 cfu/µg
DH10B family*>1 x 109 cfu/µg
TOP10 family*>1 x 109 cfu/µg
For fast routine cloning
Mach1 T1R*>1 x 109 cfu/µg

* Available in a high-throughput configuration

View more chemically competent and high transformation efficiency cells that do not require an electroporator

Specialized cloning applications

Table 2. Strains for specialty cloning applications

ApplicationE. coli strainEfficiency
Cloning unstable DNAStbl2> 1 x 109 cfu/µg
Stbl3*> 1 x 108 cfu/µg
Stbl4> 5 x 109 cfu/µg
Bacmid creationDH10Bac> 1 x 108 cfu/µg
High efficiency cloning/cDNA or genomic library constructionMegaX DH10B T1R> 3 x 1010 cfu/µg

DH5α-E

> 1 x 1010 cfu/µg
OmniMax 2 T1R

> 5 x 109 cfu/µg

Stbl4> 5 x 109 cfu/µg
DH10B family
> 1 x 1010 cfu/µg
Propagating unmethylated DNAINV110> 1 x 106 cfu/µg
Cre-lox recombination PIR1
> 1 x 109 cfu/µg
PIR2
> 1 x 108 cfu/µg
Preparing single stranded DNA (ssDNA)TOP10F´ > 1 x 109 cfu/µg
TOP10F´

> 5 x 109 cfu/µg

DH12S> 1 x 1010 cfu/µg
DH5αF´IQ> 1 x 108 cfu/µg
INVαF'
> 1 x 108 cfu/µg
Maintaining supF-containing vectorsTOP10/P3> 1 x 109 cfu/µg
MC1061/P3> 1 x 108 cfu/µg
Propagating Gateway vectors and plasmids with ccdB geneccdB Survival 2 T1R> 1 x 109 cfu/µg

*Available in a high-throughput configuration 
⚡= Electrocompetent cells

Strains for protein expression

Table 3. Strains for protein expression

ApplicationE. coli strainEfficiency
High level protein expressionBL21 (DE3)>1 x 108 cfu/µg
BL21 Star (DE3)*>1 x 108 cfu/µg
Toxic protein expressionBL21-AI>1 x 108 cfu/µg
Improved expression regulationBL21(DE3)pLysS>1 x 108 cfu/µg
BL21(DE3)pLysE>1 x 107 cfu/µg
BL21 Star (DE3)pLysS>1 x 108 cfu/µg

* Available in a high-throughput configuration


Competent cells by format

Competent cells for cloning are offered in a variety of packaging formats to fit your needs.

These competent cells are available under license for use in your services or for use in manufacturing your products for sale. Please contact us at outlicensing@thermofisher.com.


Competent cells: Featured products

In addition to competent cells, we offer a broad suite of products for the cloning workflow.

Resources

Have any questions on competent cells or transformation? Click on the resources listed below to access overviews, videos, genotype guides, and educational resources.

Icon with monitor with speech bubble onscreen.

Stay up-to-date on industry trends in molecular cloning with on-demand webinars.

Icon with two sheets of paper

Short articles and digital handbook for cloning applications

Icon of mouse inside a circle

Get support for your cloning experiments

For Research Use Only. Not for use in diagnostic procedures.

Stylesheet for Classic Wide Template adjustments