Mammalian Cell Expression System

The mammalian expression system is a vital tool in biotechnology and medicine, allowing the production of complex proteins with native-like properties. It is widely used for therapeutic protein production and functional research due to its ability to closely mimic human cell biology. Continuous improvements in transient and stable expression technology enhance both efficiency and scalability, while regulatory compliance ensures product safety and efficacy.

• Proper Protein Folding Mammalian cells possess native chaperones and cellular machinery to fold proteins correctly, preserving biological activity.
• Post-Translational Modifications (PTMs) Performs authentic mammalian PTMs—including complex N-linked and O-linked glycosylation and phosphorylation—essential for stability and function.
• Relevance to Human Biology Closely mimics human intracellular processing, making it the ideal host for therapeutic drug discovery and human target characterization.
• Complex Protein Expression Capable of expressing intricate multi-subunit proteins and membrane receptors that fail to fold in prokaryotic or simple eukaryotic hosts.
• Low Immunogenicity Proteins produced in mammalian hosts display native human-like glycan profiles, minimizing the risk of immunogenic responses in therapeutic applications.

Service Process & Deliverables

1. Plasmid Construction

15 – 20 Days

Workflow Process

• Target sequence codon optimization and custom gene synthesis
• PCR product ligation into high-expression mammalian vectors
• Transformation into Top 10 E. coli cells and colony screening
• Sequence verification to deliver sequence-confirmed recombinant plasmids

Key Feature

Vector Optimization: To maximize both expression yield and recovery, we offer custom C-terminal and N-terminal fusion tag configurations. This approach protects target bioactivity while facilitating high-purity downstream chromatography.

2. Small-Scale Screening

10 – 15 Days

Workflow Process

• Endotoxin-free preparation of transfection-grade recombinant plasmids
• Transient transfection across candidate host lines (HEK293, CHO, or custom lines)
• Target expression verification and yield quantification via SDS-PAGE and Western blot

Key Feature

Condition Optimization: We evaluate multiple transfection reagents, lipid ratios, and cell densities to establish the highest-yielding parameters prior to scale-up.

3. Scale-Up & Purification

10 – 15 Days

Workflow Process

• Large-scale culture expansion and batch transfection
• Screening of chromatographic resins and buffer conditions to determine optimal purification protocols

Key Feature

Tailored Recovery Scheme: Cell lines and purification methods are selected based on whether your protein is secreted, membrane-bound, or intracellular, maximizing total yield.

4. Optional Services

5 Days

Available Options

• Endotoxin removal (<0.1 EU/µg or <0.01 EU/µg thresholds)
• Aseptic processing, 0.22 µm filter sterilization, and custom aliquoting
• Lyophilization for extended shelf-life stability
• Enzymatic tag removal and cleavage (optional add-on)

Key Feature

Flexible downstream processing packages can be customized to meet analytical, diagnostic, or in vivo experimental thresholds.

5. QC & Release

5 Days

Workflow Process

• Purity determination via SDS-PAGE and HPLC (>85% to >98%)
• Accurate concentration quantification (BCA or A280 absorption)
• Optional SEC-MALS or bioactivity verification assays

Key Feature

Every delivered project includes a comprehensive Certificate of Analysis (COA) documenting experimental conditions and analytical QC chromatograms.

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