Efficient biomolecule purification is a critical step in downstream processing, whether for research, diagnostics, therapeutic development, or biopharmaceutical production. Selecting the right chromatography resin or purification format can help improve recovery, purity, reproducibility, and overall workflow efficiency.
Crawford Scientific supplies a specialist range of emp BIOTECH purification products designed for the isolation, purification, desalting, and buffer exchange of target biomolecules. The portfolio includes Zetadex dextran solid phases, Zetarose agarose solid phases, and ZetaCell resins for SMART Chromatography applications. These products support a wide range of purification requirements, from rapid sample clean-up and high-throughput processing to affinity, ion exchange, and hydrophobic interaction chromatography.
Dextran Solid Phase: Zetadex for Gel Filtration, Desalting, and Buffer Exchange
Zetadex is emp BIOTECH’s cross-linked, beaded dextran solid phase, developed for rapid gel filtration, desalting, and buffer exchange. The resin is composed of ultrapure cross-linked dextran and is designed to separate molecules according to size. Larger molecules, such as proteins, nucleic acids, or nanoparticles, are excluded from the bead pores and elute rapidly in the void volume, while smaller molecules such as salts, dyes, biotin, haptens, and other low molecular weight contaminants are retained within the resin matrix.
This makes Zetadex particularly useful for workflows where fast and efficient removal of small molecules is required. It can be used to desalt a sample into pure water or, when pre-equilibrated with a chosen buffer, to perform rapid buffer exchange in a single step. The resin offers high selectivity, excellent resolution, low non-specific adsorption, and robust chemical stability, with minimal buffer and pH effects on separation performance.
Two grades of Zetadex are available, each with different separation characteristics due to their degree of cross-linking:
- Zetadex-25 - molecular weight cut-off of approximately 5 kDa for proteins and 10 bases for nucleic acids.
- Zetadex-50 - molecular weight cut-off of approximately 25 kDa for proteins and 20 bases for nucleic acids.
Zetadex Formats for Fast, Flexible Sample Clean-Up
The Zetadex range is available in multiple formats to support different sample volumes, throughput requirements, and processing methods. These include flexible options for manual, centrifugal, automated, and FPLC-compatible purification workflows.
CentriPure Columns
CentriPure columns are designed for fixed sample volumes and elute with a 1.5-fold dilution. With 12 column sizes available, they can process sample volumes from 200 µL to 150 mL using gravitational flow.
CentriPure Column Arrays
The 96-array format supports 300 µL and 500 µL sample sizes in standard SLAS format, making it suitable for automated and high-throughput workflows. These arrays can process up to 96 samples simultaneously using gravitational flow or light vacuum.
CentriPure Plates
Available in 96- and 384-well SLAS formats, CentriPure plates are designed for small-volume, high-throughput applications. They support sample sizes up to 70 µL with no product dilution and include short or long drip directors to help reduce cross-contamination. Processing is carried out by centrifugation.
ZetaSpin MINI Columns
Previously known as CentriPure MINI columns, ZetaSpin MINI columns are sterile, hydrated, and ready to use. Their conical column design supports efficient separation and can remove up to 99.999% of salts, dyes, haptens, and other small molecules. Samples up to 100 µL can be processed in under five minutes by centrifugation.
ZetaSpin MIDI Columns
Previously known as CentriPure MIDI columns, ZetaSpin MIDI columns are hydrated, ready to use, and designed for sample sizes from 500 µL to 700 µL. They can remove up to 99.99% of salts, haptens, and dye-terminated samples in under 10 minutes using centrifugation.
ZetaSep Desalting Columns
ZetaSep desalting columns are suitable for buffer exchange or desalting after biomolecule purification on an FPLC system. They allow easy monitoring of the desalting process and are available in 1 mL and 5 mL column formats, with operation under pressure up to 3 bar.
Agarose Solid Phase: Zetarose for Biomolecule Purification and Separation
Zetarose is emp BIOTECH’s cross-linked, beaded agarose solid phase platform for biomolecule purification. Agarose is widely used in bioprocessing and chromatography due to its established performance, biocompatibility, and broad regulatory acceptance in pharmaceutical and biotechnology applications.
Zetarose resins are composed of spherical, highly cross-linked agarose beads and are available as Zetarose FF4, containing 4% agarose, and Zetarose FF6, containing 6% agarose. Both are supplied with an average bead size of approximately 100 µm. The
agarose concentration influences pore size, bead rigidity, and available surface area. Zetarose FF6 has smaller channels and greater rigidity, while the higher agarose content also provides increased surface area for ligand coupling and protein binding.
Zetarose Resin Chemistries for Flexible Biomolecule Purification
The Zetarose platform includes underivatised beads for gel filtration or user modification, as well as a broad range of functionalised resins for different chromatography modes, including affinity chromatography, ion exchange chromatography, and hydrophobic interaction chromatography.
Antibody Affinity Chromatography Zetarose affinity resins are used for the purification of antibodies and antibody fragments, where selective binding is essential for efficient separation. The resins use carefully engineered linker chemistry to immobilise active ligands onto highly cross-linked agarose beads, helping maintain binding performance across repeated purification cycles. A key example is Protein A Elevate, which features NaOH-tolerant Protein A ligands and supports antibody purification workflows requiring strong binding capacity, effective cleaning-in-place and repeated use.
Tag Affinity Chromatography For recombinant protein purification, Zetarose IMAC solid phases are used to isolate polyhistidine-tagged proteins. Zetarose NTA FF6 is a highly cross-linked 6% agarose resin derivatised with nitrilotriacetic acid, which can be charged with bivalent transition metal ions to selectively bind His-tagged proteins. Bound proteins can then be eluted under native or denaturing conditions using low pH buffer or buffers containing imidazole or histidine.
Hydrophobic Interaction Chromatography Zetarose HIC solid phases separate biomolecules based on differences in surface hydrophobicity, making them useful when target molecules interact differently with the stationary phase under controlled salt conditions. The range includes butyl and phenyl ligand chemistries, which provide different hydrophobic interaction strengths and give scientists practical options when optimising purification conditions for specific proteins or biomolecules.
Ion Exchange Chromatography Zetarose ion exchange resins separate biomolecules based on charge interactions and are available for both anion exchange and cation exchange workflows. Built on stable, porous, cross-linked agarose beads with a particle size centred around 100 µm, these resins provide a robust option for protein purification, supporting method development, process optimisation and scale-up.
Activated Zetarose Solid Phases Activated Zetarose solid phases are designed for applications where users need to immobilise their own ligands for targeted purification. With selected covalent binding chemistries available, the coupling approach can be matched to the ligand, target molecule and intended purification strategy, making them useful for custom affinity purification, bespoke resin development and application-specific separation workflows.
Zetarose Formats for Research, Process Development and Scale-Up
To support different stages of biomolecule purification, emp BIOTECH Zetarose resins are available in a range of practical formats, from loose bulk resin for flexible column packing to pre-packed FPLC columns and screening kits for method development. This allows scientists to explore resin chemistries, optimise purification conditions and scale workflows with greater consistency across research and production environments.
Bulk Resin
emp BIOTECH bulk Zetarose resin is available in a range of standard volumes, from 25 mL to 10 L, to support both laboratory-scale research and larger industrial purification workflows. Supplied as loose resin, it provides flexibility for packing columns, optimising methods and scaling biomolecule purification processes.
FPLC Columns
emp BIOTECH bulk Zetarose resin is available in a range of standard volumes, from 25 mL to 10 L, to support both laboratory-scale research and larger industrial purification workflows. Supplied as loose resin, it provides flexibility for packing columns, optimising methods and scaling biomolecule purification processes.
SMIRF Kits
SMIRF Kits - Simplified Method, Isolation, Recovery, Fractionation - are designed to support purification process discovery and method development. Each kit includes cross-linked agarose-based capture resin, or a selection of resins, together with a 5 mL ZetaSep desalting column, allowing purification, desalting and buffer exchange to be carried out within a connected workflow.
SMART Chromatography
SMART Chromatography - Simplified Method - Applied Radial Technology - enables biomolecules to be purified directly from the bioreactor without prior feed stream clarification, using radial flow technology to process cell-containing samples. It uses proprietary ZetaCell large-particle, highly cross-linked agarose solid phases with a range of surface modifications to support different purification requirements. Find out more about this technology in our SMART Chromatography blog.
Conclusion: Supporting Biomolecule Purification from Sample Clean-Up to Scale-Up
The emp BIOTECH purification range supplied by Crawford Scientific provides flexible, technically robust solutions for biomolecule purification, desalting, buffer exchange, and downstream process development. Zetadex dextran solid phases are ideal for rapid removal of small molecules and efficient buffer exchange, while Zetarose agarose solid phases support a broad range of chromatography techniques, including affinity, ion exchange, hydrophobic interaction, and custom ligand immobilisation.
With options ranging from centrifugal columns and high-throughput plates to bulk resins, FPLC columns, and screening kits, emp BIOTECH products can support workflows from early-stage research through to scalable purification process development. For laboratories working with proteins, antibodies, nucleic acids, nanoparticles, or other biomolecules, the range offers practical, reliable tools for improving purification performance and workflow efficiency.
