20um Streptavidin Magnetic Beads MSA10UM-10 MSA10UM-10

20µm Streptavidin Magnetic Beads MSA20UM-10

MSA20UM-10 is a 20µm streptavidin-functional magnetic bead suspension supplied at 1% solids.

The product is developed for capturing and immobilizing biotinylated antibodies, antigens, proteins, peptides, aptamers, oligonucleotides and other biotin-labelled biomolecules.

MSA20UM-10 can be evaluated as a large-particle magnetic solid phase for immunoassay research, chemiluminescence immunoassay development, target enrichment, sample pretreatment, affinity capture, immunomagnetic separation, process development and batch reagent manufacturing.

Streptavidin immobilized on the magnetic bead surface binds biotinylated ligands without requiring the end user to activate the bead surface using EDC, NHS, glutaraldehyde or another chemical activation reagent.

After loading a selected biotinylated capture ligand, the functionalized magnetic beads can be used for target capture, magnetic collection, repeated washing and downstream signal detection.

MSA20UM-10 is intended for biotechnology companies, immunoassay developers, research institutions and reagent manufacturers requiring a defined 20µm streptavidin magnetic carrier for laboratory evaluation, pilot-scale validation and bulk supply.

Because 20µm is a relatively large particle size for an analytical magnetic solid phase, compatibility with the intended assay, magnetic separator, liquid-handling system and analyzer should be validated experimentally.

Product Overview

Streptavidin magnetic beads provide a flexible affinity platform for immobilizing biotinylated biomolecules on a recoverable magnetic solid phase.

The streptavidin–biotin system allows different biotinylated antibodies, antigens, proteins and nucleic acid probes to be immobilized on the same bead platform.

Commercial streptavidin magnetic bead series include exact 20µm products, while larger 30–50µm formats are also used for antibody loading, immuno-enrichment and sample preparation.

MSA20UM-10 may be evaluated for:

• Biotinylated antibody immobilization;

• Biotinylated antigen immobilization;

• Magnetic sandwich immunoassays;

• Antibody-detection assays;

• Competitive immunoassays;

• Chemiluminescence immunoassay research;

• Electrochemiluminescence assay research;

• Sample pretreatment;

• Target enrichment;

• Affinity capture;

• Immunomagnetic separation;

• Protein-interaction studies;

• Biotinylated nucleic acid capture;

• Cell or microorganism separation research;

• Pilot-scale process validation;

• Batch reagent manufacturing.

MSA20UM-10 is supplied as a research and reagent-development raw material. It is not supplied as a finished diagnostic reagent.

MSA20UM-10 Product Specifications

When the 1% solids specification is expressed as weight per volume, it corresponds to approximately 10mg of bead material per milliliter. The concentration basis should be confirmed in the applicable product TDS.

The following product-specific parameters should be confirmed through the applicable TDS and lot-specific CoA:

• Particle-size distribution;

• Particle matrix;

• Magnetic material content;

• Streptavidin loading;

• Functional streptavidin activity;

• Free biotin-binding capacity;

• Biotinylated IgG-loading capacity;

• Biotinylated oligonucleotide-loading capacity;

• Nonspecific binding;

• Magnetic collection performance;

• Suspension buffer;

• Blocking formulation;

• Preservative system;

• Storage temperature;

• Shelf life;

• Lot-release criteria.

Competitor performance data should only be used for market benchmarking. It should not be presented as MSA20UM-10 specifications.

What Are 20µm Streptavidin Magnetic Beads?

20µm streptavidin magnetic beads are magnetic microspheres with a nominal diameter of approximately 20 micrometers and streptavidin immobilized on their surface.

The streptavidin surface captures biotinylated ligands, while the magnetic component enables the particles to be collected using a compatible magnetic separator.

Compared with commonly used 1µm, 2.8µm or 3µm analytical magnetic beads, 20µm beads represent a large-particle magnetic solid phase.

For spherical particles with similar composition and density, increasing particle diameter generally results in:

• Fewer particles per unit mass;

• Lower theoretical geometric surface area per unit mass;

• More pronounced gravity-driven settling;

• A more visible magnetic collection zone;

• Greater importance of mixing and dispensing control;

• Different liquid-handling requirements.

Actual performance also depends on particle density, magnetic material content, particle-size distribution, surface coating, streptavidin density, suspension buffer and magnet design.

How Does Streptavidin–Biotin Binding Work?

Streptavidin immobilized on the magnetic bead surface recognizes biotin attached to an antibody, antigen, protein, peptide or oligonucleotide.

The resulting affinity structure can be represented as:

Magnetic bead–streptavidin–biotin–ligand

The biotinylated ligand provides biological target recognition, while the magnetic particle provides a recoverable solid phase for separation, washing and reagent handling.

Streptavidin-coated particles are widely used as matrices for capturing biotinylated proteins, immunoglobulins, DNA, RNA and other biotin-labelled molecules.

Biotinylated Capture Antibody Format

A magnetic sandwich immunoassay may include:

1. Prepare a biotinylated capture antibody.

2. Incubate the antibody with MSA20UM-10.

3. Allow the biotin groups to bind to surface streptavidin.

4. Magnetically collect the antibody-loaded beads.

5. Remove unbound antibody.

6. Resuspend the loaded beads in the selected formulation.

7. Incubate the beads with the sample.

8. Capture the target antigen.

9. Add a labelled detection antibody.

10. Magnetically collect and wash the immune complex.

11. Generate the selected detection signal.

12. Measure the analytical response.

Biotinylated Antigen Format

For an antibody-detection assay:

1. Prepare a biotinylated antigen.

2. Load the antigen onto MSA20UM-10.

3. Remove unbound antigen.

4. Incubate the functionalized beads with the sample.

5. Capture target-specific antibodies.

6. Add a labelled secondary antibody.

7. Perform magnetic collection and washing.

8. Measure the resulting signal.

Biotinylated Oligonucleotide Format

Biotinylated DNA, RNA or aptamer probes may be immobilized for:

• Nucleic acid capture;

• Hybridization assays;

• Target enrichment;

• Probe immobilization;

• Aptamer-based detection;

• Pull-down experiments;

• Sample preparation before amplification.

The position and degree of biotinylation should be selected to preserve hybridization, target-recognition or aptamer activity.

Key Features of MSA20UM-10

Defined 20µm Particle Size

MSA20UM-10 provides a defined nominal 20µm bead format rather than a broad large-particle range.

A controlled particle size can help researchers standardize:

• Bead dispensing;

• Ligand loading;

• Magnetic collection;

• Washing;

• Redispersion;

• Sample pretreatment;

• Pilot production;

• Lot-to-lot comparison.

Streptavidin-Functional Surface

The bead surface can capture different biotinylated ligands, including:

• Monoclonal antibodies;

• Polyclonal antibodies;

• Recombinant antigens;

• Natural proteins;

• Peptides;

• Enzymes;

• Aptamers;

• DNA probes;

• RNA probes;

• Oligonucleotides;

• Hapten conjugates;

• Other biotin-labelled recognition molecules.

1% Solids Formulation

When expressed as w/v, 1% solids corresponds to approximately 10mg/mL.

Approximate bead-mass calculations are:

• 10µL contains approximately 0.1mg;

• 50µL contains approximately 0.5mg;

• 100µL contains approximately 1mg;

• 500µL contains approximately 5mg;

• 1mL contains approximately 10mg.

These calculations should only be used after confirming that the product concentration is expressed as w/v.

No Additional Bead Activation Required

A properly biotinylated ligand can normally be loaded without activating the bead surface using EDC/NHS or another covalent coupling reagent.

This can simplify development because several biotinylated capture molecules can be compared using the same magnetic bead platform.

Clearly Observable Magnetic Collection

Under an appropriate magnetic field, 20µm particles may form a clearly observable collection zone.

This may help researchers monitor:

• Completion of magnetic collection;

• Bead loss during aspiration;

• Particle aggregation;

• Washing consistency;

• Redispersion after collection.

Actual magnetic collection should be confirmed using the intended magnet, vessel, bead concentration, sample volume and buffer formulation.

Suitable for Research-to-Production Projects

MSA20UM-10 can support:

• Initial material screening;

• Biotinylated ligand evaluation;

• Immunoassay development;

• Sample-pretreatment optimization;

• Target-enrichment studies;

• Stability evaluation;

• Pilot-scale processing;

• Batch-consistency testing;

• Bulk raw-material procurement.

Why Choose 20µm Streptavidin Magnetic Beads?

Large Magnetic Solid Phase

MSA20UM-10 may be evaluated when a project requires a larger magnetic carrier than commonly used 1–5µm analytical beads.

Potential reasons include:

• Clearly observable magnetic collection;

• Manual or semi-automated washing;

• Sample pretreatment;

• Target enrichment;

• Capture of relatively large biological targets;

• Compatibility with an existing 20µm material specification.

Convenient Manual Process Monitoring

Large magnetic beads may be easier to observe during:

• Magnetic collection;

• Supernatant removal;

• Repeated washing;

• Aggregation inspection;

• Particle-loss troubleshooting;

• Redispersion testing.

Potential for Target Enrichment

Biotinylated affinity ligands loaded onto MSA20UM-10 may be evaluated for enriching or removing:

• Proteins;

• Antigens;

• Antibodies;

• Cells;

• Microorganisms;

• Biological particles;

• Nucleic acids;

• Other affinity-recognized targets.

Large-particle streptavidin magnetic products are commercially used for antibody immuno-enrichment and sample-preparation workflows.

Important Surface-Area Tradeoff

For spherical particles with similar material and density, increasing particle diameter reduces particle number and theoretical geometric surface area per unit mass.

A procedure developed with 1µm, 3µm, 5µm or 10µm beads should not be transferred directly to 20µm beads.

The following parameters should be re-optimized:

• Bead dosage;

• Ligand-to-bead ratio;

• Ligand-loading time;

• Mixing conditions;

• Target-incubation time;

• Washing conditions;

• Final bead concentration.

Automation Requires Careful Validation

MSA20UM-10 may be evaluated for selected automated or semi-automated systems, but compatibility should not be assumed.

Main validation items include:

• Reagent-reservoir mixing;

• Particle settling during standby;

• Pipette-tip internal diameter;

• Tubing dimensions;

• Valve clearance;

• Bead-dispensing accuracy;

• Reaction-vessel geometry;

• Magnet position;

• Magnetic collection time;

• Aspiration height;

• Washing efficiency;

• Redispersion;

• Carryover;

• Fluidic blockage risk.

Small-particle streptavidin magnetic beads are often specifically validated with dedicated automated platforms, which illustrates why a 20µm product must be separately tested with the intended instrument.

20µm vs Smaller Streptavidin Magnetic Beads

Particle diameter should not be the only selection criterion.

Other important factors include:

• Particle-size distribution;

• Magnetic material content;

• Particle matrix;

• Streptavidin density;

• Active biotin-binding capacity;

• Blocking formulation;

• Nonspecific binding;

• Suspension buffer;

• Magnetic recovery;

• Functional assay performance.

The preferred particle size should be selected through side-by-side functional testing in the intended workflow.

Applications in Immunoassay Reagent Development

MSA20UM-10 may be evaluated for:

• Magnetic sandwich immunoassays;

• Antibody-detection assays;

• Competitive immunoassays;

• Chemiluminescence immunoassay research;

• Electrochemiluminescence assay research;

• Immunomagnetic target enrichment;

• Sample pretreatment;

• Affinity capture;

• Immunoprecipitation research;

• Protein-interaction studies;

• Biotinylated nucleic acid capture;

• Cell or microorganism separation.

The suitability of the 20µm format depends on the target, sample matrix, reaction vessel, magnetic separator and downstream detection system.

Chemiluminescence Immunoassay Research

A biotinylated capture antibody can be loaded onto MSA20UM-10.

The antibody-loaded beads capture the target antigen from the sample. A labelled detection antibody then forms an immune complex.

After magnetic collection and washing, the detection label generates the chemiluminescent signal.

Important development variables include:

• Bead dosage;

• Capture-antibody loading;

• Degree of antibody biotinylation;

• Sample volume;

• Target-capture time;

• Detection-antibody concentration;

• Washing efficiency;

• Chemiluminescent substrate;

• Signal-to-background ratio.

Because 20µm is larger than the particle sizes used by many automated CLIA systems, analyzer compatibility must be confirmed experimentally.

Antibody-Detection Assays

A biotinylated antigen may be immobilized on MSA20UM-10 to capture target-specific antibodies.

Potential research applications include:

• Infectious-disease antibody assays;

• Autoantibody assays;

• Vaccine-response studies;

• Recombinant antigen evaluation;

• Antibody-response monitoring.

Competitive Immunoassays

Biotinylated antigens, haptens or small-molecule conjugates may be evaluated in competitive assay formats.

This approach may be suitable when the analyte cannot support a conventional two-antibody sandwich structure.

Electrochemiluminescence Research

MSA20UM-10 may be evaluated in ECL research when the magnetic positioning module, electrode configuration and fluidic pathway are compatible with 20µm particles.

The development team should validate:

• Particle positioning near the electrode;

• Magnetic recovery;

• Electrode interference;

• Washing efficiency;

• Reaction-vessel geometry;

• Fluidic clearance;

• Signal chemistry;

• Carryover.

Applications in Sample Pretreatment and Target Enrichment

MSA20UM-10 may be evaluated for sample-preparation workflows where magnetic recovery and repeated washing are important.

Potential applications include:

• Target-protein enrichment;

• Antigen capture;

• Antibody purification;

• Cell separation;

• Microorganism enrichment;

• Biological particle capture;

• Nucleic acid enrichment;

• Sample cleanup;

• Removal of interfering components.

Larger streptavidin magnetic systems are commercially used for immunoprecipitation, protein purification, nucleic acid purification and biological target enrichment.

Compatible Biotinylated Antibodies and Biomolecules

Biotinylated Antibodies

Important antibody variables include:

• Antibody purity;

• Antibody concentration;

• Biotinylation chemistry;

• Degree of biotinylation;

• Biotin position;

• Aggregation status;

• Retained antigen-binding activity;

• Original formulation buffer.

Excessive biotinylation may reduce biological activity or produce an unfavourable orientation after immobilization.

Insufficient biotinylation may reduce bead loading and functional target capture.

Biotinylated Antigens

Biotinylated antigens may be used for antibody-detection assays.

The developer should confirm that biotinylation does not modify or block an important epitope.

Biotinylated Peptides

Potential applications include:

• Antibody screening;

• Epitope analysis;

• Competitive assays;

• Protein-interaction studies;

• Affinity capture.

Biotinylated Oligonucleotides

Biotin may be introduced at the 5′ end, 3′ end or another validated position.

The selected modification position should preserve hybridization, elongation or aptamer activity.

Biotinylated Proteins and Enzymes

Biotinylated proteins and enzymes may be evaluated for:

• Protein-interaction studies;

• Enzyme assays;

• Affinity enrichment;

• Biosensor development;

• Calibration-material preparation.

Recommended Biotinylated Ligand Loading Workflow

The following workflow is a general development framework. It is not a validated product-specific protocol.

Step 1: Characterize the Biotinylated Ligand

Record:

• Ligand identity;

• Molecular weight;

• Concentration;

• Purity;

• Original formulation;

• Biotinylation method;

• Estimated degree of biotinylation;

• Biological activity;

• Aggregation status;

• Stabilizing additives.

Step 2: Remove Excess Free Biotin

Free biotin can occupy available streptavidin-binding sites and reduce loading of the intended biotinylated ligand.

Potential purification methods include:

• Desalting;

• Dialysis;

• Size-exclusion chromatography;

• Ultrafiltration;

• HPLC or FPLC;

• Another validated purification process.

Spherotech specifically notes that free biotin and small unbound biotinylated compounds can bind faster than larger biotinylated molecules.

Step 3: Fully Resuspend MSA20UM-10

Mix the original suspension until homogeneous before removing an aliquot.

Suitable methods may include:

• Gentle inversion;

• Roller mixing;

• End-over-end rotation;

• Controlled low-speed vortexing;

• Another validated low-foam method.

Because 20µm particles can settle during storage and temporary process holds, suitable mixing should be maintained when preparing multiple aliquots.

Step 4: Calculate the Required Bead Quantity

When the concentration is confirmed as 10mg/mL:

Bead mass = suspension volume × 10mg/mL

Evaluate several bead doses rather than testing only one condition.

Step 5: Wash or Equilibrate the Beads

Collect the magnetic beads using a compatible separator.

Remove the original suspension medium when required and equilibrate the particles in a validated ligand-loading buffer.

Do not allow the particles to dry.

Step 6: Add the Biotinylated Ligand

Evaluate several ligand-to-bead ratios:

• Low ligand loading;

• Medium ligand loading;

• High ligand loading;

• Different incubation times;

• Different temperatures;

• Different buffer formulations.

Step 7: Maintain Uniform Mixing

Use sufficient mixing to prevent settling and maintain bead–ligand contact without damaging the biological ligand.

Large-particle streptavidin bead protocols emphasize maintaining a uniform suspension during ligand loading and aliquoting.

Step 8: Magnetically Collect the Loaded Beads

Standardize:

• Magnet type;

• Vessel;

• Reaction volume;

• Bead concentration;

• Collection time;

• Collection position;

• Residual liquid volume.

Step 9: Retain the Supernatant

Retain the post-loading supernatant when ligand-loading efficiency needs to be measured.

Step 10: Wash the Loaded Beads

Remove:

• Unbound biotinylated ligand;

• Residual free biotin;

• Unwanted formulation components;

• Other unbound materials.

Step 11: Resuspend in the Final Buffer

Potential formulation components include:

• Buffer;

• Salt;

• Protein stabilizer;

• Synthetic polymer;

• Surfactant;

• Preservative;

• Sugar or polyol;

• Blocking component.

The final formulation should be optimized for bead dispersion, ligand activity, low background and storage stability.

Step 12: Evaluate Functional Performance

Recommended tests include:

• Ligand-loading efficiency;

• Functional target capture;

• Blank signal;

• Positive signal;

• Signal-to-background ratio;

• Magnetic recovery;

• Bead redispersion;

• Precision;

• Accelerated stability;

• Real-time stability.

How to Optimize MSA20UM-10

Optimize Bead Dosage

Too few beads may limit target capture.

Too many beads may increase:

• Reagent consumption;

• Blank signal;

• Nonspecific adsorption;

• Washing requirements;

• Residual particle interference;

• Instrument carryover.

Optimize Ligand Loading

Evaluate several quantities of biotinylated antibody or antigen per milligram of beads.

The highest chemical loading does not necessarily provide the best functional result.

Excessive loading may cause:

• Steric crowding;

• Reduced target accessibility;

• Increased nonspecific binding;

• Reduced functional activity;

• Poorer storage stability.

Optimize the Degree of Biotinylation

Compare ligands with different biotinylation levels.

Evaluate:

• Bead-loading efficiency;

• Retained biological activity;

• Target-capture performance;

• Blank signal;

• Positive signal;

• Precision;

• Stability.

Optimize Mixing

Because 20µm particles can settle, evaluate:

• Continuous versus intermittent mixing;

• Mixing speed;

• Mixing duration;

• Vessel geometry;

• Suspension uniformity;

• Foam formation;

• Ligand stability.

Optimize Magnetic Separation

Evaluate:

• Magnet strength;

• Magnet position;

• Collection time;

• Vessel geometry;

• Bead concentration;

• Sample volume;

• Buffer viscosity;

• Residual liquid;

• Bead loss during aspiration.

Optimize Washing

Compare:

• Wash-buffer composition;

• Surfactant concentration;

• Wash volume;

• Number of wash cycles;

• Mixing during washing;

• Magnetic collection time;

• Residual wash volume.

Insufficient washing may increase assay background. Excessive or aggressive washing may reduce particle recovery or affect sensitive biological components.

Optimize Automated or Semi-Automated Processing

Evaluate:

• Reservoir mixing frequency;

• Settling during standby;

• Bead-dispensing accuracy;

• Pipette-tip and tubing dimensions;

• Valve clearance;

• Incubation mixing;

• Magnetic collection;

• Aspiration height;

• Wash cycles;

• Residual volume;

• Redispersion;

• Carryover;

• Fluidic blockage risk.

How to Evaluate Biotin-Binding Performance

Total Biotin-Binding Capacity

A labelled biotin reagent may be used to estimate available streptavidin-binding sites.

Different suppliers use different particles, test ligands, units and analytical procedures. MSA20UM-10 should therefore have its own validated method and internal acceptance range.

Biotinylated Antibody Loading

Measure the antibody concentration before and after bead loading.

An approximate calculation is:

Loaded antibody = Initial antibody − Unbound antibody

Potential analytical methods include:

• UV absorbance;

• BCA assay;

• Bradford assay;

• Fluorescence measurement;

• ELISA;

• Another validated protein assay.

Functional Target-Capture Capacity

Chemical ligand loading does not confirm retained biological activity.

Functional testing should measure actual target capture under representative assay conditions.

Nonspecific Binding

Compare:

• Unloaded beads;

• Ligand-loaded beads;

• Blocked beads;

• Negative samples;

• Positive samples;

• Representative interfering substances.

Magnetic Recovery

Measure bead recovery after repeated magnetic collection and washing.

Functional Assay Performance

Evaluate:

• Blank signal;

• Negative-sample signal;

• Low-positive signal;

• High-positive signal;

• Signal-to-background ratio;

• Precision;

• Recovery;

• Linearity;

• Specificity;

• Hook effect;

• Stability.

Quality Control for Research and Batch Production

Physical Properties

Recommended physical quality-control items include:

• Appearance;

• Dispersion;

• Particle size;

• Particle-size distribution;

• Solids content;

• Sedimentation behaviour;

• Ease of redispersion.

Functional Surface Properties

Recommended surface-performance tests include:

• Streptavidin activity;

• Free biotin-binding capacity;

• Biotinylated antibody loading;

• Biotinylated oligonucleotide loading;

• Nonspecific binding.

Magnetic Performance

Use standardized conditions for:

• Magnet type;

• Vessel;

• Buffer;

• Sample volume;

• Bead concentration;

• Collection time;

• Temperature.

Functional Immunoassay Performance

Evaluate:

• Blank signal;

• Positive signal;

• Signal-to-background ratio;

• Analytical sensitivity;

• Precision;

• Recovery;

• Specificity;

• Stability.

Lot-to-Lot Consistency

For routine production, establish acceptance ranges for:

• Particle size;

• Particle-size distribution;

• Solids content;

• Streptavidin activity;

• Biotin-binding capacity;

• Magnetic recovery;

• Dispersion;

• Nonspecific binding;

• Functional assay performance.

Final raw-material approval should be based on performance in the complete customer assay or separation workflow.

Scale-Up and Bulk Supply for Reagent Manufacturers

Evaluation Stage

Evaluation samples can support screening of:

• Biotinylated antibodies;

• Biotinylated antigens;

• Bead dosage;

• Ligand-loading level;

• Blocking formulation;

• Magnetic separation;

• Target capture;

• Assay background.

Pilot-Scale Stage

Pilot quantities can support:

• Ligand-loading process confirmation;

• Reagent formulation;

• Instrument compatibility testing;

• Stability studies;

• Filling-process evaluation;

• Initial lot-consistency testing.

Batch-Production Stage

Bulk-supply planning may include:

• Annual demand;

• Purchase forecast;

• Packaging volume;

• Quality specifications;

• Technical documentation;

• Quality documentation;

• Reserved-lot requirements;

• Change-control expectations;

• Safety-stock planning.

Scale-Up Considerations

A laboratory procedure should not be scaled only by multiplying reagent volumes.

Revalidate:

• Vessel geometry;

• Mixing efficiency;

• Bead-suspension uniformity;

• Ligand-addition sequence;

• Incubation time;

• Temperature distribution;

• Magnetic collection;

• Washing efficiency;

• Process hold time;

• Final filling uniformity.

Maintaining a homogeneous suspension during ligand loading and final filling is particularly important for 20µm particles.

Custom Streptavidin Magnetic Bead Services

SHBC can evaluate customized requirements for biotechnology companies, research institutions and reagent manufacturers.

Potential customization options include:

• Alternative particle sizes;

• Customized solids content;

• Adjusted streptavidin loading;

• Customer-specific biotin-binding targets;

• Alternative blocking formulations;

• Customized suspension buffer;

• Alternative preservative systems;

• Customer-specified pH;

• Special packaging volumes;

• Pilot-scale production;

• Bulk manufacturing;

• OEM packaging;

• Private-label services;

• Customer-specific quality testing.

Customization feasibility depends on the requested specifications, intended application, validation requirements and order quantity.

Storage and Handling Recommendations

Store MSA20UM-10 according to the product label, TDS and lot-specific CoA.

General handling recommendations include:

• Mix thoroughly before sampling;

• Maintain suspension uniformity during dispensing;

• Use clean and calibrated equipment;

• Avoid allowing the magnetic beads to dry;

• Prevent microbial and chemical contamination;

• Avoid freezing unless specifically validated;

• Avoid unnecessary exposure to extreme temperatures;

• Confirm buffer compatibility before buffer exchange;

• Prevent contamination with free biotin;

• Record the product lot number;

• Evaluate ligand-loaded bead stability separately.

Commercial streptavidin magnetic bead instructions recommend keeping the particles in liquid, preventing drying and avoiding freezing.

Large micrometer-scale beads may settle during storage and temporary process holds. The suspension should therefore be fully homogenized before each sampling, loading or filling operation.

Frequently Asked Questions

What is MSA20UM-10?

MSA20UM-10 is a 20µm streptavidin-functional magnetic bead suspension supplied at 1% solids for capturing biotinylated biomolecules in immunoassay research, sample pretreatment, target enrichment and batch reagent manufacturing.

What does 1% solids mean?

When expressed as w/v, 1% solids corresponds to approximately 10mg of magnetic bead material per milliliter. The concentration basis should be confirmed in the product TDS.

Which molecules can MSA20UM-10 capture?

The beads may be evaluated for binding biotinylated antibodies, antigens, proteins, peptides, aptamers, DNA, RNA and other biotin-labelled molecules.

Does MSA20UM-10 require EDC/NHS activation?

No additional EDC/NHS activation is normally required for loading a properly biotinylated ligand.

Is a capture antibody included?

No. MSA20UM-10 is supplied as a streptavidin magnetic bead raw material. The customer selects and prepares the required biotinylated antibody, antigen or other capture ligand.

Is the 1% suspension ready to use directly?

Not necessarily. The optimal working concentration depends on the ligand, target, sample volume, assay format and magnetic separation system.

Why choose a 20µm particle size?

The 20µm format may be evaluated when a project requires a large magnetic solid phase, clearly observable collection, repeated washing, sample pretreatment, target enrichment or compatibility with an existing 20µm material specification.

Do 20µm magnetic beads settle?

Yes. Large micrometer-scale magnetic particles can settle during storage, incubation and process holds. The suspension should be mixed before sampling and maintained under suitable mixing during processing.

How do 20µm beads differ from 10µm beads?

For particles made from similar materials, 20µm beads generally provide fewer individual particles and less theoretical geometric surface area per unit mass, while showing more pronounced settling and different magnetic collection behaviour.

How do 20µm beads differ from 1–3µm beads?

Smaller particles generally provide more particles and greater geometric surface area per unit mass. The 20µm format may be easier to observe but requires greater attention to mixing, settling and fluidic compatibility.

Can MSA20UM-10 be used for immunoassay development?

MSA20UM-10 can be evaluated as a magnetic solid phase in immunoassay research. Performance must be validated using the intended ligand, sample matrix, magnetic separator and detection system.

Can MSA20UM-10 be evaluated for CLIA?

It may be evaluated for chemiluminescence immunoassay development when the reaction vessel, magnetic separator and liquid-handling system are compatible with 20µm particles.

Can it be evaluated for electrochemiluminescence assays?

It may be evaluated in ECL research. Compatibility with the electrode, magnetic positioning module, fluidic pathway and signal chemistry must be confirmed experimentally.

Can MSA20UM-10 be used with automated analyzers?

It may be evaluated for selected automated or semi-automated systems. Dispensing, mixing, magnetic collection, aspiration, washing and fluidic-path compatibility must be validated.

How much biotinylated antibody should be loaded?

The optimal amount depends on the product’s validated binding capacity, antibody molecular weight, degree of biotinylation and application requirements. Several loading levels should be compared.

Does higher antibody loading always improve performance?

No. Excessive ligand loading may cause steric crowding, reduce target accessibility and increase nonspecific binding.

Can free biotin interfere with ligand loading?

Yes. Free biotin can occupy available streptavidin-binding sites and reduce loading of the intended biotinylated ligand.

How can ligand-loading efficiency be measured?

Compare the initial ligand quantity with the amount of unbound ligand remaining in the post-loading supernatant. Functional target-capture activity should also be evaluated.

How should MSA20UM-10 be mixed?

Use a validated method such as gentle inversion, roller mixing, end-over-end rotation or controlled low-speed vortexing until the suspension is homogeneous.

What should be checked if magnetic collection is incomplete?

Evaluate:

• Magnet strength;

• Magnet position;

• Collection time;

• Bead concentration;

• Sample volume;

• Buffer viscosity;

• Particle aggregation;

• Vessel geometry.

What should be checked if ligand loading is low?

Evaluate:

• Degree of biotinylation;

• Free biotin contamination;

• Ligand concentration;

• Bead quantity;

• Incubation time;

• Buffer compatibility;

• Ligand aggregation.

What should be checked if assay background is high?

Evaluate:

• Blocking formulation;

• Bead dosage;

• Ligand-loading density;

• Washing efficiency;

• Sample matrix;

• Nonspecific adsorption;

• Detection-reagent concentration.

Is MSA20UM-10 a finished diagnostic reagent?

No. MSA20UM-10 is supplied as a raw material for research and reagent development. The customer is responsible for validating the finished reagent, manufacturing process and intended application.

Are evaluation samples and bulk quantities available?

Evaluation, pilot and bulk-supply requirements can be discussed according to the intended application, estimated annual demand and required packaging format.

Can the concentration, buffer or packaging be customized?

Customized solids content, streptavidin loading, suspension buffer, blocking formulation and packaging format may be evaluated according to project requirements.

Request a Sample or Bulk Quotation

Contact SHBC to request an evaluation sample, technical information or bulk quotation for MSA20UM-10 20µm Streptavidin Magnetic Beads.

Please provide:

• Intended immunoassay or separation application;

• Biotinylated antibody, antigen or other ligand;

• Ligand molecular weight;

• Biotinylation method;

• Estimated degree of biotinylation;

• Sample matrix;

• Magnetic separator or analyzer;

• Required evaluation quantity;

• Estimated pilot quantity;

• Expected annual demand;

• Preferred packaging volume;

• Required technical documents;

• Required quality documents;

• Target development schedule;

• Custom specification requirements.

SHBC supports streptavidin magnetic bead projects from ligand-loading evaluation and immunoassay optimization to pilot validation and bulk manufacturing.