Quality control

Quality control

The quality control platform developed by Xpress Biologics includes a large range of equipment / techniques dedicated to the characterization of the purified material:

  • ready-to-use methods: SDS-PAGE, AGE, IEF, µBCA, pH, conductivity, spectrophotometry, endotoxin, Bioburden
  • methods requiring specific development: WB, RP-, SE- & IEx-HPLC, HCP, rDNA, restriction mapping, ELISA, activity tests

The purified material (recombinant protein and plasmid) is characterized using the following assays:

Tests Methods for recombinant proteins Methods for plasmids

Physical state

pH, conductivity and appearance

Identity

SDS-PAGE

Restriction mapping

Western blotting

DNA sequencing

Iso-electrofocusing

Mass spectroscopy (ESI-Q-TOF, peptide mapping)

RP- & IEx-HPLC

Content

µBCA

Spectrophotometry - A260

Spectrophotometry - A280

Purity

SDS-PAGE (reducing and non-reducing conditions)

Spectrophotometry - ratio A260/A280

RP & IEx-HPLC

Topology by agarose gel electrophoresis

SE-HPLC

Topology by IEx-HPLC

Impurity

Residual host cell proteins by ELISA

Residual host cell proteins by µBCA

Residual host cell DNA by threshold

Residual host cell DNA by q-PCR

Residual host cell RNA by agarose gel electrophoresis or HPLC

Safety

Endotoxin content by LAL

Bioburden

Potency

Specific test (ELISA, specific activity…)

Specific test