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Enhance recombinant protein purification with chromatography
Recombinant therapeutic proteins—including hormones, enzymes, and fusion proteins—require chromatography-based downstream purification workflows that can vary significantly by target molecule. Selective chromatography technologies, such as target-specific affinity chromatography and affinity tagging via C-tag platform purification, can support higher yields and purities per batch. This helps reduce the total number of downstream processing steps, therefore reducing costs. The CaptureSelect affinity portfolio and POROS polishing resins are designed to address these needs from bench-scale research through commercial GMP manufacturing.
Purification complexity across protein targets
Recombinant protein targets span a wide range of physicochemical properties, presenting distinct challenges at each stage of downstream processing (DSP).
Molecular size, surface charge, and hydrophobicity vary considerably across the therapeutic protein landscape from smaller hormones such as human growth hormone (hGH), to large, heavily glycosylated proteins such as follicle-stimulating hormone (FSH) and human chorionic gonadotropin (hCG). Expression system selection further complicates the purification strategy, as different host cell systems, such as bacterial, yeast, insect, or mammalian, generate distinct host cell protein (HCP) impurity profiles that must be addressed in the downstream workflow.
Without a selective capture step, purification workflows typically require multiple sequential chromatography and intermediate processing steps. As a result, development timelines extend, process complexity increases, and production costs rise.
Benefits of affinity-based purification
Three primary purification strategy approaches are available for recombinant proteins:
- Traditional functionalized chromatography resins, such as ion exchange (IEX) and hydrophobic interaction chromatography (HIC), can achieve adequate purity but require multiple sequential steps.
- Target-specific affinity resin development, in which a resin is designed against a known protein target, can enable single-step, high-purity capture from complex feedstocks.
- The C-tag platform enables affinity purification of tagged recombinant proteins when no target-specific resin is available.
Affinity-based approaches can reduce the number of purification steps, increase product yield, reduce bioprocess development time, and lower overall cost of goods. CaptureSelect affinity resins use VHH single-domain antibody fragments as ligands, produced through an animal origin-free (AOF) process.
Affinity capture for recombinant protein purification
The CaptureSelect affinity chromatography resin portfolio is designed to serve as the capture-step solution across a range of recombinant protein purification workflows. The portfolio includes target-specific affinity resins developed for individual recombinant protein targets, organized by protein class.
CaptureSelect hormone-specific affinity resins are designed for selective single-step capture of recombinant hormone targets from cell culture harvests. Corresponding ligand leakage ELISAs are available for bioprocess-format products.
Bioprocess manufacturing and research resins
Resin |
Application |
Corresponding ligand leakage ELISA |
CaptureSelect FSH (follicle-stimulating hormone) Affinity Matrix |
Designed for binding intact follicle-stimulating hormone at the alpha/beta chain interface |
CaptureSelect FSH (follicle-stimulating hormone) Ligand Leakage ELISA |
CaptureSelect hCG (human chorionic gonadotropin) Affinity Matrix |
Designed for binding human chorionic gonadotropin, with cross-reactivity to luteinizing hormone (LH) due to shared alpha subunit structure |
CaptureSelect hCG (human chorionic gonadotropin) Ligand Leakage ELISA |
Used for highly selective purification of hGH with retained biological activity; available in bioprocess and research formats |
CaptureSelect hGH (human growth hormone) Ligand Leakage ELISA |
|
CaptureSelect TSH (thyroid-stimulating hormone) Affinity Matrix |
Designed for binding TSH without cross-reactivity to other gonadotropins (FSH, LH, or hCG) |
CaptureSelect TSH (thyroid-stimulating hormone) Ligand Leakage ELISA |
Research-use only (RUO) resins
Resin |
Application |
Designed for the purification of EPO and darbepoetin (DPO) |
Tissue plasminogen activator (tPA) is a serine protease used as a thrombolytic agent to treat acute ischemic stroke and other thrombotic conditions.
Bioprocess manufacturing and research resins
Resin |
Application |
Corresponding ligand leakage ELISA |
CaptureSelect tPA (tissue plasminogen activator) Affinity Matrix |
Designed for selective binding of tPA in the presence of magnesium chloride at neutral pH, enabling single-step capture from cell culture harvests while preserving enzymatic activity | CaptureSelect tPA (tissue plasminogen activator) Ligand Leakage ELISA |
When a target-specific affinity resin is not available for a given recombinant protein, affinity tags offer a flexible approach to purification through generic binding interactions with a single platform resin.
Bioprocess manufacturing and research resins
Resin |
Application |
Corresponding ligand leakage ELISA |
Designed for the high affinity, selective purification of C-terminally tagged proteins from complex mixtures including cell culture harvests and periplasmic fractions |
Albumin fusion is a widely used strategy to extend the serum half-life or modify the pharmacokinetics of recombinant peptide and protein therapeutics.
Bioprocess manufacturing and research resins
Resin |
Application |
Corresponding ligand leakage ELISA |
Used for the purification of recombinant albumin fusion proteins, with mild elution properties designed to support gentle elution and preserve protein integrity |
CaptureSelect HSA (human serum albumin) Ligand Leakage ELISA |
Research-use only (RUO) resins
Resin |
Application |
Used for the purification of granulocyte-macrophage colony-stimulating factor (GM-CSF), enabling purification of this cytokine with high purity and yield in a single step |
Polishing steps in recombinant protein manufacturing
Following affinity capture with CaptureSelect resins, process-related impurities, including HCPs, host DNA, aggregates, product variants, endotoxins, and residual impurities from the expression system, must be addressed in one or more downstream polishing steps. POROS IEX, HIC, and Mixed-mode chromatography (MMC) resins are designed for these polishing applications.
Depending on the target and impurity profiles, one to three polishing steps are typically required to meet the purity and molecular quality specifications for clinical or commercial use. The POROS resin platform is characterized by high binding capacity, high resolution, rigid poly(styrene-divinylbenzene) backbone, and chemical stability even under stringent clean-in-place (CIP) regimes.
IEX resins separate proteins based on differences in surface charge, enabling selective removal of impurities or capture of target proteins in bind-elute or flow-through modes. The following POROS IEX resins are suited for recombinant protein polishing workflows:
Cation exchange chromatography (CEX) resins
Resin |
Application |
High-capacity strong cation exchanger suited for polishing recombinant proteins, monoclonal antibodies (mAbs), and viruses |
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High-capacity strong cation exchanger suited for polishing recombinant proteins, mAbs, and viruses, with high-salt tolerance, increased dynamic binding capacity (DBC), and different selectivity compared to POROS 50 HS |
Anion exchange chromatography (AEX) resins
Resin |
Application |
| Suited for purification of recombinant proteins and viral clearance applications. With partial quaternized amine chemistry, selectivity is driven by interactions with multiple amine types, and is especially suited for difficult separations of large molecules and flow-through applications. | |
Suited for purification of recombinant proteins and viral clearance applications. With fully quaternized amine chemistry, selectivity is driven through predominantly strong ionic interactions, enabling high salt tolerance and high dynamic binding capacity. |
Resin selection between CEX and AEX depends on the isoelectric point (pI) and charge profile of the target recombinant protein as well as the main contaminants under the intended operating conditions.
HIC resins separate proteins based on differences in surface hydrophobicity, making them a useful complementary polishing tool for removing aggregates, high-molecular-weight species, and product-related impurities following affinity capture.
POROS HIC resins span both ends of the hydrophobicity scale and support method development across a broad range of protein targets:
Resin |
Application |
Ethyl surface chemistry suited for bind-elute purification of moderately hydrophobic molecules, with lower hydrophobicity relative to benzyl-based chemistries |
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| Low-density benzyl/aromatic chemistry suited for bind-elute or flow-through operation, presenting high hydrophobicity | |
High-density benzyl chemistry suited for flow-through aggregate removal applications, with even higher hydrophobicity than POROS Benzyl |
Mixed-mode chromatography (MMC) resins combine ionic and hydrophobic interaction mechanisms within a single functional group, offering orthogonal selectivity that is beneficial when standard single-mode resins do not fully resolve the impurity profile of a recombinant protein feedstream.
For recombinant protein workflows where aggregate clearance or HCP reduction remains challenging after IEX and HIC steps, MMC can be a useful additional polishing option. By operating across a broad range of buffer conditions, it reduces aggregates and process-related impurities while maintaining monomer recovery.
Resin |
Application |
POROS Caprylate Mixed-Mode Cation Exchange Chromatography Resin |
Combines hydrophobic and weak cation exchange functionality in flow-through mode, with scalability from process development through commercial GMP manufacturing |
Related resources
Frequently asked questions
CaptureSelect affinity resins for hormone purification include CaptureSelect FSH (follicle-stimulating hormone) Affinity Matrix, CaptureSelect hCG (human chorionic gonadotropin) Affinity Matrix, CaptureSelect hGH (human growth hormone) Affinity Matrix, CaptureSelect TSH (thyroid-stimulating hormone) Affinity Matrix, and CaptureSelect EPO (erythropoietin) Affinity Matrix. Each resin uses a VHH nanobody ligand designed for high selectivity to its specific hormone target, enabling single-step capture from cell culture harvests. Bioprocess-grade resins include corresponding ligand leakage ELISAs.
The C-tag system uses a four-amino acid peptide tag (E-P-E-A) incorporated at the C-terminus of the target protein during expression construct design. CaptureSelect C-tagXL Affinity Matrix then captures C-tagged proteins with high affinity and selectivity from complex feedstocks, including cell culture harvests and periplasmic fractions. This approach is well-suited for recombinant proteins for which no target-specific affinity resin is available in the catalog, offering a versatile single-resin platform for diverse protein targets.
Yes, CaptureSelect and POROS resins are fully scalable to commercial GMP manufacturing and can be used in large production columns. They are available in research-scale screening formats, including RoboColumns™, GoPure plates, and MiniChrom™ columns, and in bioprocess-scale bulk quantities, using the same resin chemistry at each stage of development. Select products in this portfolio are suited for commercial GMP manufacturing and clinical-stage use.
Following affinity capture, POROS ion exchange chromatography resins are designed to separate impurities from target molecules based on charge differences. POROS XS and POROS 50 HS are used for cation exchange, while POROS 50 HQ and POROS XQ are used for anion exchange. POROS HIC resins, such as POROS Ethyl, POROS Benzyl, and POROS Benzyl Ultra, allow the separation of impurities and target molecules based on hydrophobicity differences. POROS Caprylate Mixed-Mode Cation Exchange Resin has a ligand with both charge and hydrophobicity characteristics, offering an additional tool to help achieve desired separation. Resin selection depends on the target protein's physicochemical properties and the impurity profile generated by the expression system.
Where the same or comparable resin chemistry is available in both research and bioprocess formats, the transition from a research-scale resin to a bioproduction-scale resin can follow a structured scale-up and process transfer pathway. Because the same ligand chemistry and base matrix are used across formats, process characterization data generated at the research scale can support method development and regulatory documentation at the production scale, helping reduce re-development time.
Additional bioprocessing resources
Bioprocessing resources
For research and development use only in support of FDA-regulated end uses. Not for diagnostic use or direct administration to humans or animals.