Master cell banking
Microbial master cell banking for plasmid DNA production
A robust, traceable master cell bank is the foundation of consistent, high‑quality plasmid DNA manufacturing.
Our comprehensive cell banking services are designed to safeguard cell line integrity, ensure long‑term supply, and support seamless progression from development through to commercial production.
Our microbial master cell banks are created to preserve a uniform population of cells, maintain genetic stability, and provide sufficient material for the entire lifecycle of your product.
Why work with NHS Blood and Transplant?
Established platform
We offer an established master cell banking service built on 20 years of experience, with more than 100 cell banks manufactured in that time.
We also provide qualified quality control, stability and storage.
Excellence in quality
We are compliant with Medicines and Healthcare products Regulatory Agency (MHRA) good manufacturing practice (GMP) standards, ensuring high quality through:
- dedicated GMP cell banking clean rooms
- single‑use, gamma‑irradiated and/or sanitised components
- our robust quality management system
- comprehensive in-house quality control
Our cell banking process
Cell line selection
We can work with your preferred bacterial host strain or recommend suitable strains tailored to your plasmid and process requirements. Our cell line selection studies identify the most suitable host based on:
- comprehensive characterisation
- disabled phenotypes for enhanced safety
- proven performance in transformation, replication, and plasmid DNA production
E. coli strains used for master cell bank generation are supplied as chemically competent cells by reputable commercial manufacturers or prepared internally under controlled batch procedures. All strains undergo quality control (QC) identity testing before release for GMP use.
Clone selection
Transformant clones are screened for plasmid yield and plasmid quality, including assessment of plasmid forms, to identify and eliminate clonal variability. This ensures the selected clone performs optimally in upstream processes.
Cell expansion
Selected clones are expanded using controlled suspension bioreactor systems to achieve the required biomass for cell banking.
Cryopreservation
The master cell bank is aliquoted into up to 200 labelled 2 mL cryovials under a biological safety cabinet and cryopreserved at -80°C to ensure secure, long‑term storage and consistency across production campaigns.
Quality control
All cell banks undergo validated QC testing to meet stringent GMP expectations. This includes identity, purity, viability, and plasmid integrity assessments.
Regulatory compliance
Every master cell bank and working cell bank is supplied with a full certificate of analysis, ensuring complete traceability and compliance with global regulatory expectations.