1.5um Streptavidin Magnetic Beads MSA1.5UM-10 1%

1.5µm Streptavidin Magnetic Beads MSA1.5UM-10

MSA1.5UM-10 is a 1.5µm streptavidin-functional magnetic bead suspension supplied at 1% solids.

When the solids content is expressed as weight per volume, 1% corresponds to approximately 10mg of magnetic beads per milliliter of suspension.

The product is developed for the capture and immobilization of biotinylated antibodies, antigens, proteins, peptides, aptamers, oligonucleotides and other biotin-labelled molecules.

MSA1.5UM-10 can be evaluated as a magnetic solid phase in chemiluminescence immunoassay research, magnetic immunoassay development, biomolecule enrichment, sample preparation, process scale-up and batch reagent manufacturing.

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

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

MSA1.5UM-10 is intended for biotechnology companies, immunoassay reagent developers, research institutions and manufacturing enterprises requiring a 1.5µm streptavidin magnetic bead raw material for laboratory evaluation, pilot production and bulk supply.

The finished reagent should be validated using the intended biotinylated ligand, sample matrix, magnetic separator, chemiluminescent detection chemistry and analyzer.

Product Overview

The streptavidin–biotin system provides a flexible method for immobilizing different biotinylated molecules on a common magnetic bead surface.

Commercial magnetic beads with particle sizes at or close to 1.5µm are used for enzyme immunoassays, biotinylated protein separation, cell sorting and DNA probe applications. Exact 1.5µm products and 1.5–1.9µm ranges are available from established particle manufacturers.

MSA1.5UM-10 is designed to support:

• Biotinylated antibody immobilization;

• Biotinylated antigen immobilization;

• Magnetic sandwich immunoassays;

• Antibody-detection assays;

• Competitive immunoassays;

• Chemiluminescence immunoassay development;

• Immunomagnetic enrichment;

• Biotinylated peptide capture;

• Nucleic acid and aptamer capture;

• Automated reagent development;

• Pilot-scale manufacturing;

• Batch production.

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

MSA1.5UM-10 Product Specifications

The following product-specific parameters should be confirmed through the applicable technical data sheet and lot-specific certificate of analysis:

• Particle-size distribution;

• Streptavidin activity;

• Biotin-binding capacity;

• Magnetic collection performance;

• Suspension buffer;

• Blocking formulation;

• Preservative system;

• Storage temperature;

• Shelf life;

• Lot-release specifications.

How Do Streptavidin Magnetic Beads Work?

Streptavidin is immobilized on the magnetic bead surface and provides binding sites for biotin.

When a biotinylated antibody, antigen, protein, peptide or oligonucleotide is incubated with MSA1.5UM-10, the biotin group binds to streptavidin on the particle surface.

The resulting complex can be represented as:

Magnetic bead–streptavidin–biotin–ligand

The loaded ligand provides biological recognition, while the magnetic particle provides a solid phase for collection, washing and reagent handling.

Streptavidin-coated magnetic particles are widely used to separate biotinylated proteins, immunoglobulins, nucleic acids and other biotin-labelled molecules.

Example Using a Biotinylated Capture Antibody

A typical sandwich immunoassay workflow may include:

1. Prepare a biotinylated capture antibody.

2. Incubate the antibody with MSA1.5UM-10.

3. Remove unbound antibody.

4. Resuspend the antibody-loaded beads.

5. Incubate the beads with the sample.

6. Capture the target antigen.

7. Add a labelled detection antibody.

8. Magnetically collect and wash the immune complex.

9. Add the chemiluminescent detection reagent.

10. Measure the analytical signal.

Example Using a Biotinylated Antigen

For an antibody-detection assay:

1. Biotinylate the selected antigen.

2. Load the antigen onto MSA1.5UM-10.

3. Incubate the functionalized beads with the sample.

4. Capture target-specific antibodies.

5. Add a labelled secondary antibody.

6. Perform magnetic washing.

7. Measure the signal.

Example Using a Biotinylated Oligonucleotide

A biotinylated oligonucleotide can be immobilized for:

• Nucleic acid capture;

• Hybridization assays;

• Aptamer-based detection;

• Target enrichment;

• Probe immobilization;

• Molecular diagnostic research.

The position and degree of biotinylation should be selected to preserve the ligand’s target-binding activity.

Key Features of MSA1.5UM-10

Defined 1.5µm Particle Size

MSA1.5UM-10 provides a defined 1.5µm magnetic bead format rather than a broad particle-size range.

The particle size may influence:

• Number of particles per unit mass;

• Available geometric surface area;

• Ligand accessibility;

• Suspension behaviour;

• Magnetic collection;

• Washing efficiency;

• Redispersion;

• Automated liquid handling.

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

Streptavidin-Functional Surface

The bead surface provides binding sites for biotinylated ligands.

Potential ligands include:

• Biotinylated monoclonal antibodies;

• Biotinylated polyclonal antibodies;

• Biotinylated recombinant antigens;

• Biotinylated natural proteins;

• Biotinylated peptides;

• Biotinylated enzymes;

• Biotinylated aptamers;

• Biotinylated DNA probes;

• Biotinylated RNA probes;

• Other biotin-labelled affinity molecules.

1% Solids Formulation

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

Approximate bead-mass calculations are:

• 10µL contains approximately 0.1mg of beads;

• 50µL contains approximately 0.5mg of beads;

• 100µL contains approximately 1mg of beads;

• 500µL contains approximately 5mg of beads;

• 1mL contains approximately 10mg of beads.

These calculations should be used only after confirming that the product specification 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 chemical crosslinker.

This can simplify early-stage immunoassay development and reduce variation associated with separate bead-activation procedures.

Flexible Ligand Screening

The same magnetic bead platform can be evaluated with several biotinylated capture molecules.

This supports:

• Capture-antibody screening;

• Antibody-pair comparison;

• Antigen-construct evaluation;

• Peptide screening;

• Aptamer screening;

• Assay-target expansion;

• Multiproduct reagent development.

Magnetic Solid-Phase Handling

After ligand loading and target capture, the particles can be collected using a compatible magnetic separator.

A typical process includes:

• Bead dispensing;

• Sample incubation;

• Target capture;

• Magnetic collection;

• Supernatant removal;

• Washing;

• Detection-reagent incubation;

• Additional magnetic washing;

• Signal generation.

Research-to-Production Supply

MSA1.5UM-10 can support:

• Initial feasibility testing;

• Biotinylated ligand screening;

• Immunoassay optimization;

• Automated-analyzer evaluation;

• Stability studies;

• Pilot manufacturing;

• Lot-consistency assessment;

• Bulk raw-material procurement.

Why Choose 1.5µm Streptavidin Magnetic Beads?

Intermediate Micrometer-Scale Particle Format

The 1.5µm size is larger than a nominal 1µm particle while remaining substantially smaller than common 3µm, 5µm or larger magnetic carriers.

It can be evaluated when developers require a balance among:

• Available particle surface;

• Magnetic collection;

• Suspension behaviour;

• Washing;

• Redispersion;

• Automated handling.

The optimal size must be determined experimentally in the intended assay.

Practical Magnetic Collection

A 1.5µm particle may provide different magnetic collection behaviour from a smaller nominal 1µm product.

Actual collection time depends on:

• Magnetic loading;

• Magnet strength;

• Vessel geometry;

• Bead concentration;

• Buffer viscosity;

• Sample volume;

• Particle aggregation.

Suitable for Repeated Washing

Chemiluminescence immunoassays commonly require multiple magnetic separation and washing cycles.

MSA1.5UM-10 can be evaluated for workflows requiring:

• Repeatable bead recovery;

• Controlled aspiration;

• Low particle loss;

• Consistent redispersion;

• Defined residual wash volume.

Familiar 1% Starting Concentration

A 1% concentration is used by several commercial streptavidin magnetic bead products, although particle size, surface chemistry and binding capacity vary between manufacturers.

The 1% formulation can provide a convenient starting point for:

• Ligand-loading studies;

• Bead-dosage screening;

• Manual assay development;

• Automated reagent formulation;

• Competitive product comparison.

Potential Automated-Platform Compatibility

MSA1.5UM-10 may be evaluated for automated chemiluminescence immunoassay analyzers.

Parameters requiring validation include:

• Reagent-reservoir mixing;

• Bead-dispensing accuracy;

• Reaction-cup geometry;

• Incubation mixing;

• Magnet position;

• Collection time;

• Aspiration height;

• Wash volume;

• Residual liquid;

• Bead recovery;

• Redispersion;

• Carryover.

Compatibility should be established on the specific analyzer.

Applications in Chemiluminescence Immunoassay Development

Magnetic Sandwich Immunoassays

A biotinylated capture antibody can be loaded onto MSA1.5UM-10.

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

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

Important development variables include:

• Bead dosage;

• Capture-antibody loading;

• Degree of antibody biotinylation;

• Sample volume;

• Capture time;

• Detection-antibody concentration;

• Wash efficiency;

• Chemiluminescent substrate;

• Signal-to-background ratio.

Antibody-Detection Assays

A biotinylated antigen can be immobilized on MSA1.5UM-10 to capture specific antibodies from research samples.

Potential applications include:

• Infectious-disease antibody research;

• Autoantibody assays;

• Vaccine-response studies;

• Recombinant antigen evaluation;

• Antibody-response monitoring.

Competitive Immunoassays

Biotinylated antigens, haptens or small-molecule conjugates can be evaluated for competitive assay development.

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

Indirect Immunoassay Formats

MSA1.5UM-10 may also be evaluated with:

• Biotinylated secondary antibodies;

• Biotinylated anti-species antibodies;

• Biotinylated affinity proteins;

• Biotinylated peptides;

• Biotinylated aptamers.

Immunomagnetic Enrichment

Biotinylated affinity ligands loaded onto the beads can be evaluated for enrichment of:

• Proteins;

• Antigens;

• Cells;

• Microorganisms;

• Biological particles;

• Other affinity-recognized targets.

Nucleic Acid and Aptamer Capture

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

• Hybridization assays;

• Nucleic acid enrichment;

• Target capture before amplification;

• Aptamer-based detection;

• Biosensor development;

• Molecular diagnostic research.

Immunoprecipitation and Affinity Capture

Biotinylated antibodies or affinity ligands can also be loaded for:

• Immunoprecipitation research;

• Protein interaction studies;

• Pull-down assays;

• Affinity capture;

• Sample cleanup.

Bangs Laboratories positions its approximately 1.5µm streptavidin particles for enzyme immunoassays, cell sorting, DNA probe assays and magnetic separation of biotinylated complexes.

Compatible Biotinylated Antibodies and Biomolecules

Biotinylated Antibodies

Important antibody variables include:

• Purity;

• Concentration;

• Biotinylation chemistry;

• Degree of biotinylation;

• Position of biotin modification;

• Aggregation status;

• Retained antigen-binding activity;

• Original formulation buffer.

Excessive biotinylation may reduce biological activity or create unfavourable orientation on the bead surface.

Insufficient biotinylation may produce low loading.

Biotinylated Antigens

Biotinylated antigens can be used for antibody-detection assays.

The developer should confirm that biotinylation does not modify or block a critical epitope.

Biotinylated Peptides

Potential applications include:

• Antibody screening;

• Epitope analysis;

• Competitive assays;

• Protein-interaction research;

• Affinity capture.

Biotinylated Oligonucleotides

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

The selected position should preserve hybridization or aptamer activity after immobilization.

Biotinylated Proteins and Enzymes

Biotinylated recombinant proteins or enzymes may be used 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 Ligand

Record:

• Ligand identity;

• Molecular weight;

• Concentration;

• Purity;

• Original buffer;

• Biotinylation method;

• Estimated degree of biotinylation;

• Biological activity;

• Aggregation status;

• Stabilizing additives.

Step 2: Remove Excess Free Biotin

Free biotin and small unbound biotinylated compounds can occupy streptavidin-binding sites before the intended biotinylated antibody or protein is loaded.

Spherotech specifically advises removing excess free biotin or free biotinylated primers because they can bind more rapidly than larger biotinylated molecules.

Potential purification approaches include:

• Desalting;

• Dialysis;

• Size-exclusion chromatography;

• Ultrafiltration;

• HPLC or FPLC where appropriate;

• Another validated purification method.

Step 3: Fully Resuspend MSA1.5UM-10

Mix the suspension until homogeneous before sampling.

Possible methods include:

• Gentle inversion;

• Roller mixing;

• End-over-end rotation;

• Controlled vortexing;

• Another validated mixing method.

Avoid excessive foam.

Step 4: Calculate the Required Bead Mass

Assuming a concentration of 10mg/mL:

Bead mass = suspension volume × 10mg/mL

Prepare multiple bead-dose groups instead of evaluating only one condition.

Step 5: Wash or Equilibrate the Beads

Collect the beads using a compatible magnetic separator.

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

Step 6: Add the Biotinylated Ligand

Evaluate several ligand-to-bead ratios.

Possible screening groups include:

• Low ligand loading;

• Medium ligand loading;

• High ligand loading;

• Different loading times;

• Different temperatures;

• Different buffer compositions.

Step 7: Maintain Gentle Mixing

Use sufficient mixing to keep the particles uniformly distributed without damaging the biological ligand.

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.

Step 12: Evaluate Functional Performance

Recommended tests include:

• Ligand-loading efficiency;

• Target-capture capacity;

• Blank signal;

• Positive signal;

• Signal-to-background ratio;

• Magnetic recovery;

• Bead redispersion;

• Precision;

• Accelerated stability;

• Real-time stability.

How to Optimize MSA1.5UM-10 in an Immunoassay

Optimize Bead Dosage

Compare several bead quantities in the complete assay.

Too few beads may limit target capture.

Too many beads may increase:

• Reagent consumption;

• Blank signal;

• Nonspecific adsorption;

• Washing requirements;

• Residual bead interference;

• Instrument carryover.

Optimize Ligand Loading

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

The condition with the highest ligand loading is not necessarily the best analytical condition.

Excessive loading may produce:

• Steric crowding;

• Reduced target accessibility;

• Higher 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 Loading Time

The required loading time depends on:

• Ligand size;

• Biotin accessibility;

• Bead concentration;

• Mixing;

• Temperature;

• Buffer composition.

Optimize Blocking and Storage Formulation

Potential formulation variables include:

• Protein blockers;

• Synthetic blocking polymers;

• Nonionic surfactants;

• Ionic strength;

• Sugars;

• Polyols;

• Preservatives.

The final formulation should support bead dispersion, low background, streptavidin activity and ligand stability.

Optimize Magnetic Separation

Evaluate:

• Magnet strength;

• Magnet position;

• Collection time;

• Reaction-vessel geometry;

• Bead concentration;

• 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.

Optimize Automated Analyzer Parameters

For automated CLIA development, evaluate:

• Reagent-reservoir mixing;

• Bead-dispensing accuracy;

• Incubation mixing;

• Magnetic collection time;

• Aspiration height;

• Wash cycles;

• Residual volume;

• Bead redispersion;

• Carryover.

How to Evaluate Biotin-Binding and Functional Performance

Total Biotin-Binding Capacity

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

Competitors express binding capacity using different units, such as picomoles of biotin per milligram of beads or micrograms of biotinylated material per milligram. These values depend on the test molecule and method and should not be transferred directly to MSA1.5UM-10.

MSA1.5UM-10 should have its own validated method and internal acceptance range.

Biotinylated Antibody Loading

Measure the antibody amount before and after loading.

An approximate calculation is:

Loaded antibody = Initial antibody − Unbound antibody

Possible analytical methods include:

• UV absorbance;

• BCA assay;

• Bradford assay;

• Fluorescent protein measurement;

• ELISA;

• Another validated protein assay.

Functional Target-Capture Capacity

Chemical loading does not confirm that the antibody or antigen remains biologically active.

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

Non-Specific Binding

Compare:

• Unloaded streptavidin beads;

• Ligand-loaded beads;

• Blocked beads;

• Negative samples;

• Positive samples;

• Representative interfering materials.

Magnetic Recovery

Measure the percentage of beads recovered after repeated magnetic collection and washing.

Immunoassay Performance

Evaluate:

• Blank signal;

• Negative-sample signal;

• Low-positive signal;

• High-positive signal;

• Signal-to-background ratio;

• Precision;

• Recovery;

• Linearity;

• Hook effect;

• Stability.

Quality Control for Research and Batch Production

Appearance and Dispersion

Inspect:

• Suspension appearance;

• Visible aggregation;

• Sedimentation behaviour;

• Homogeneity after mixing;

• Ease of redispersion;

• Stability during process holds.

Particle Size and Distribution

Confirm the nominal 1.5µm particle size using an appropriate validated method.

For batch production, monitor both average particle size and particle-size distribution.

Solids Content

Verify solids concentration because it affects:

• Bead-mass calculations;

• Ligand-loading calculations;

• Assay formulation;

• Filling accuracy;

• Production yield.

Streptavidin Activity

Use a standardized biotin-binding test to evaluate functional streptavidin activity on the particle surface.

Biotin-Binding Capacity

Establish a validated test method and internal acceptance range.

Competitor values should only be used as development benchmarks, not as specifications for MSA1.5UM-10.

Biotinylated Antibody Loading

Use a representative biotinylated antibody to evaluate practical loading performance.

Magnetic Collection Performance

Standardize:

• Magnet;

• Vessel;

• Sample volume;

• Buffer;

• Bead concentration;

• Temperature;

• Collection time.

Non-Specific Binding

Evaluate background using representative proteins, antibodies and sample matrices.

Functional CLIA Performance

Recommended tests include:

• Blank signal;

• Negative-sample signal;

• Positive-sample signal;

• Signal-to-background ratio;

• Analytical sensitivity;

• Precision;

• Recovery;

• Linearity;

• Specificity;

• Stability.

Lot-to-Lot Consistency

For routine manufacturing, establish acceptance ranges for:

• Particle size;

• Particle-size distribution;

• Solids content;

• Streptavidin activity;

• Biotin-binding capacity;

• Magnetic collection;

• Dispersion;

• Functional immunoassay performance.

Final material approval should be based on performance in the complete assay system.

Scale-Up and Bulk Supply for Immunoassay Manufacturers

Evaluation Stage

Evaluation samples can support screening of:

• Biotinylated capture antibodies;

• Biotinylated antigens;

• Bead dosage;

• Ligand-loading level;

• Blocking formulation;

• Magnetic separation;

• Assay sensitivity;

• Background signal.

Pilot-Scale Stage

Pilot quantities can support:

• Ligand-loading process confirmation;

• Reagent formulation;

• Analyzer compatibility testing;

• Stability studies;

• Filling-process evaluation;

• Initial lot-consistency testing.

Batch-Production Stage

Bulk-supply planning may include:

• Annual demand;

• Purchasing forecast;

• Packaging volume;

• Quality specifications;

• Technical documentation;

• Quality documentation;

• Reserved-lot requirements;

• Change-control expectations;

• Safety-stock planning.

Scale-Up Considerations

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

The following parameters should also be revalidated:

• Vessel geometry;

• Mixing efficiency;

• Bead homogeneity;

• Ligand-addition sequence;

• Incubation time;

• Temperature uniformity;

• Magnetic collection;

• Washing efficiency;

• Process hold time;

• Final filling uniformity.

Custom Streptavidin Magnetic Bead Services

SHBC can evaluate customized streptavidin magnetic bead requirements for biotechnology companies, research institutions and immunoassay manufacturers.

Potential customization options include:

• Alternative particle sizes;

• Customized solids content;

• Adjusted streptavidin loading;

• Customer-specific biotin-binding targets;

• Alternative blocking systems;

• Customized suspension buffer;

• Alternative preservatives;

• Customer-specified pH;

• Special packaging volumes;

• Pilot-scale manufacturing;

• Bulk manufacturing;

• OEM packaging;

• Private-label services;

• Customer-specific quality testing.

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

Storage and Handling Recommendations

Store MSA1.5UM-10 according to the product label, technical data sheet and lot-specific certificate of analysis.

General recommendations include:

• Mix thoroughly before sampling;

• Maintain suspension uniformity during dispensing;

• Use clean and calibrated equipment;

• Avoid allowing the 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 approximately 1.5µm streptavidin particles are commonly stored under refrigerated conditions, and suppliers warn that freezing or drying can cause aggregation or loss of performance. Product-specific conditions for MSA1.5UM-10 should be confirmed in its own documentation.

Frequently Asked Questions

What is MSA1.5UM-10?

MSA1.5UM-10 is a 1.5µm streptavidin-functional magnetic bead suspension supplied at 1% solids for capturing biotinylated biomolecules in immunoassay research, CLIA development and batch manufacturing.

What does 1% solids mean?

When expressed as w/v, 1% solids corresponds to approximately 10mg of magnetic beads per milliliter of suspension.

Which molecules can MSA1.5UM-10 capture?

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

What is the binding principle?

Biotin on the selected ligand binds to streptavidin immobilized on the magnetic bead surface.

Does MSA1.5UM-10 require EDC or NHS activation?

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

Is a capture antibody included?

No. MSA1.5UM-10 is supplied as a streptavidin magnetic bead raw material. The customer selects and prepares the required biotinylated capture ligand.

Is the 1% suspension ready to use directly?

Not necessarily. The optimal working concentration depends on the ligand, target concentration, assay volume, sample matrix and instrument.

Why choose a 1.5µm particle size?

The 1.5µm format can be evaluated when the developer requires an intermediate micrometer-scale particle with different surface, settling and magnetic collection characteristics from nominal 1µm or larger beads.

What is the difference between 1µm and 1.5µm streptavidin beads?

The two sizes may differ in particle number per unit mass, geometric surface area, magnetic collection, sedimentation and automated handling. The best size should be selected through side-by-side assay testing.

Can MSA1.5UM-10 be used for chemiluminescence immunoassays?

It can be evaluated as a magnetic solid phase in CLIA development. Compatibility with the complete reagent system and analyzer must be validated.

Can it be used with automated immunoassay analyzers?

It may be evaluated for automated systems. Dispensing, mixing, magnetic collection, aspiration, washing and redispersion must be validated on the specific analyzer.

How much biotinylated antibody should be loaded?

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

Does more antibody always improve sensitivity?

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

Can free biotin interfere with loading?

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

How can loading efficiency be measured?

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

Can non-biotinylated antibodies bind specifically?

Non-biotinylated antibodies are not expected to bind specifically through the streptavidin–biotin interaction. Observed binding may result from nonspecific adsorption.

How should MSA1.5UM-10 be mixed?

Mix using a validated method such as inversion, roller mixing, end-over-end rotation or controlled vortexing until homogeneous.

What should be checked if magnetic collection is incomplete?

Check:

• Magnet strength;

• Collection time;

• Bead concentration;

• 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;

• Loading time;

• Buffer compatibility;

• Ligand aggregation.

What should be checked if the assay background is high?

Evaluate:

• Blocking formulation;

• Bead dosage;

• Ligand-loading density;

• Wash efficiency;

• Sample matrix;

• Nonspecific adsorption;

• Detection-reagent concentration.

Is MSA1.5UM-10 a finished diagnostic reagent?

No. MSA1.5UM-10 is supplied as a raw material for research and reagent development. The customer is responsible for validating the finished reagent, production process and intended application.

Are evaluation samples available?

Evaluation samples can be discussed according to the intended application, biotinylated ligand and required testing quantity.

Is bulk supply available?

Pilot-scale and bulk supply can be arranged for qualified research, development and manufacturing projects.

Can the concentration, buffer or packaging be customized?

Customized solids content, streptavidin loading, suspension buffer, blocking system 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 MSA1.5UM-10 1.5µm Streptavidin Magnetic Beads.

Please provide:

• Intended immunoassay application;

• Biotinylated antibody, antigen or other ligand;

• Ligand molecular weight;

• Biotinylation method;

• Estimated degree of biotinylation;

• 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 early ligand-loading evaluation and chemiluminescence immunoassay optimization to pilot production and bulk manufacturing.