3um Streptavidin Microspheres SAPS3UM-10 1%

3µm Streptavidin Microspheres for Flow Cytometry

SHBC SAPS3UM-10 Streptavidin Microspheres are 3µm surface-functionalized microspheres developed for immobilizing biotinylated antibodies, antigens, proteins, peptides, oligonucleotides, DNA, RNA, aptamers, and other biotin-labeled biomolecules.

The product is supplied as a 1% solids suspension and is designed for flow cytometry assay development, bead-based immunoassay research, biomolecule interaction studies, nucleic acid capture, particle-based detection, and research reagent manufacturing.

Shanghai SanYu Biotechnology Co., Ltd. supports laboratory sample evaluation, pilot-scale development, repeated production, and bulk supply for biotechnology companies, research institutes, flow cytometry laboratories, reagent manufacturers, and assay-development organizations.

Quick Product Answer

SAPS3UM-10 is a 3µm streptavidin-coated microsphere suspension supplied at 1% solids. Its streptavidin-functional surface binds biotinylated biomolecules and can be used to develop flow cytometry bead assays, affinity capture systems, immunoassays, nucleic acid detection methods, and multiplex particle-based research platforms.

Product Highlights

• Product name: 3µm Streptavidin Microspheres

• Catalog number: SAPS3UM-10

• Brand: SHBC

• Manufacturer: Shanghai SanYu Biotechnology Co., Ltd.

• Nominal particle diameter: 3µm

• Surface modification: Streptavidin

• Solids content: 1%

• Binding principle: Streptavidin–biotin affinity

• Physical form: Aqueous microsphere suspension

• Primary application: Flow cytometry assay research

• Supply capability: Samples, pilot batches, and bulk production

• Customization: Available according to technical feasibility

• Intended use: Research use only

What Are SAPS3UM-10 Streptavidin Microspheres?

SAPS3UM-10 consists of 3µm microspheres with streptavidin immobilized on the particle surface.

The streptavidin coating provides binding sites for biotinylated molecules. Researchers can load a selected biotinylated antibody, antigen, protein, peptide, nucleic acid probe, or other ligand onto the microspheres without carrying out direct covalent activation of the microsphere surface.

After the biotinylated capture molecule has been immobilized, the functionalized particles can be used as a solid phase for target capture, fluorescence detection, biomolecular interaction analysis, immunoassay development, and flow cytometry measurement.

Potential biotinylated ligands include:

• Monoclonal antibodies

• Polyclonal antibodies

• Recombinant antibodies

• Antibody fragments

• Antigens

• Recombinant proteins

• Peptides

• Enzymes

• Receptors

• Lectins

• Oligonucleotide probes

• DNA probes

• RNA probes

• Aptamers

• Biotinylated small molecules

The 3µm diameter provides a micron-sized particle population that can generally produce stronger scatter signals than smaller submicron or 1µm particles on many conventional flow cytometers.

This makes SAPS3UM-10 suitable for researchers who want a streptavidin-coated particle platform that is relatively easy to detect, gate, wash, and analyze.

SAPS3UM-10 is supplied as a raw material for research and assay development. It is not supplied as a finished diagnostic reagent, certified flow cytometry calibration standard, or absolute counting bead.

SAPS3UM-10 Technical Specifications

The following parameters should be confirmed using the final technical specification or lot-specific Certificate of Analysis:

• Particle matrix

• Measured mean particle diameter

• Particle-size distribution

• Particle-size coefficient of variation

• Streptavidin coating density

• Biotin-binding capacity

• Particle number concentration

• Suspension buffer

• Buffer pH

• Stabilizer or surfactant

• Preservative

• Package size

• Shelf life

• Storage conditions

Binding capacity should be stated using a defined test molecule, testing method, calculation basis, and lot-specific result.

The 1% solids concentration should not be used by itself to estimate biotin-binding capacity or particle number concentration.

How Streptavidin–Biotin Binding Works

Streptavidin is a biotin-binding protein that can capture biotinylated biomolecules through a strong non-covalent interaction.

When a biotinylated ligand is mixed with SAPS3UM-10, the biotin group binds to available streptavidin sites on the microsphere surface.

The resulting structure can be represented as:

Microsphere Surface – Streptavidin – Biotin – Capture Ligand

For an antibody assay, the structure may be:

Microsphere – Streptavidin – Biotinylated Capture Antibody

The immobilized capture antibody can bind its target antigen. A fluorescently labeled detection antibody can then recognize another site on the captured antigen, generating a microsphere-associated fluorescence signal that can be measured by flow cytometry.

Benefits of Streptavidin–Biotin Immobilization

• No EDC/NHS activation is normally required for ligand loading.

• One microsphere platform can be used with many biotinylated ligands.

• The assay designer can change the capture molecule without changing the base particle.

• Immobilization can be completed under relatively mild aqueous conditions.

• Biotinylated antibodies, proteins, peptides, and nucleic acid probes can be used.

• The platform is suitable for modular assay development.

• Ligand loading can be optimized independently from downstream detection.

• The same microsphere format may support single-target or multiplex research.

Final performance depends on ligand biotinylation, biotin accessibility, spacer length, molecular size, streptavidin density, incubation conditions, surface crowding, and assay matrix.

Why Choose 3µm Streptavidin Microspheres?

Easier Flow Cytometry Detection Than Smaller Particles

The 3µm particle diameter may generate stronger forward-scatter and side-scatter signals than 1µm or submicron microspheres on many conventional flow cytometers.

This can help researchers:

• Locate the microsphere population

• Separate microspheres from buffer background

• Establish a stable scatter gate

• Identify possible aggregates

• Evaluate singlet and doublet populations

• Confirm particle recovery after washing

• Perform routine flow cytometry acquisition

Instrument performance varies, so detection should still be confirmed using the intended flow cytometer.

Suitable Surface Area for Biomolecule Immobilization

A 3µm microsphere provides a physical surface for immobilizing biotinylated capture molecules.

The usable binding capacity depends on:

• Streptavidin coating density

• Streptavidin activity

• Ligand molecular size

• Biotinylation level

• Spacer design

• Steric accessibility

• Ligand concentration

• Incubation conditions

A larger particle does not automatically guarantee a higher reported binding capacity per milligram. Lot-specific testing is required.

Convenient Washing and Recovery

Micron-sized particles may be easier to recover using a validated centrifugation or filtration process than smaller particles.

The most suitable separation method depends on:

• Particle density

• Particle matrix

• Sample volume

• Centrifugal force

• Centrifugation time

• Tube material

• Buffer composition

• Required recovery rate

SAPS3UM-10 should not be assumed to be magnetic unless magnetic properties are specifically stated in its technical documentation.

Flexible Assay Design

Researchers can use the same streptavidin microsphere platform with different biotinylated capture molecules.

This supports rapid development of assays targeting different proteins, antibodies, antigens, nucleic acids, receptors, or ligands.

Suitable for Research-to-Production Scale-Up

SAPS3UM-10 can be evaluated in a laboratory-scale assay and then transferred to pilot or bulk manufacturing after specifications have been confirmed.

This is suitable for organizations that require:

• Initial research samples

• Multiple development lots

• Pilot-scale verification

• Batch-to-batch comparison

• Long-term supply

• OEM packaging

• Customer-specific quality control

Key Features and Benefits

3µm Nominal Particle Diameter

The micron-sized particle population is suitable for optimized flow cytometry detection, scatter gating, bead-based binding assays, and particle tracking.

Streptavidin-Functional Surface

The surface captures biotinylated antibodies, proteins, peptides, oligonucleotides, aptamers, and other biotin-containing molecules.

1% Solids Suspension

SAPS3UM-10 is supplied at 1% solids and can be diluted according to the required particle number, assay volume, event rate, and binding capacity.

Simple Ligand Immobilization

Biotinylated ligands can be loaded without direct carbodiimide activation of the microsphere by the end user.

Modular Assay Platform

The base microsphere can be combined with different biotinylated capture molecules for multiple research projects.

Compatible with Fluorescent Reporter Detection

A flow cytometry signal can be generated using fluorescent detection antibodies, secondary antibodies, probes, or other reporters.

Suitable for Singleplex and Multiplex Research

SAPS3UM-10 can be evaluated as one microsphere population in a particle-based multiplex system.

Bulk Production Capability

SHBC supports laboratory samples, pilot batches, repeat orders, and bulk manufacturing.

Custom Development Options

Particle size, concentration, streptavidin coating, binding capacity, buffer, packaging, fluorescence coding, and quality-control requirements may be discussed for qualified projects.

Applications in Flow Cytometry Research

Bead-Based Sandwich Immunoassays

SAPS3UM-10 may be used as the solid phase in a flow cytometry sandwich immunoassay.

A typical workflow includes:

1. Immobilizing a biotinylated capture antibody.

2. Blocking the microsphere surface.

3. Incubating the particles with the sample.

4. Capturing the target antigen.

5. Adding a fluorescent detection antibody.

6. Washing away unbound reagents.

7. Measuring microsphere-associated fluorescence by flow cytometry.

Potential research targets include:

• Cytokines

• Hormones

• Growth factors

• Antibodies

• Antigens

• Enzymes

• Biomarkers

• Pathogen-associated proteins

• Environmental analytes

• Research compounds

Competitive Flow Cytometry Assays

The microspheres may also be evaluated in competitive assay formats.

In a competitive assay, the measured fluorescence signal may decrease or increase depending on how the sample target competes with a labeled or immobilized reagent.

Competitive formats may be relevant for:

• Small molecules

• Peptides

• Haptens

• Drugs

• Toxins

• Hormones

• Targets with only one accessible binding site

Biotinylated Antibody Capture

Biotinylated antibodies can be immobilized on SAPS3UM-10 for:

• Antigen detection

• Antibody screening

• Hybridoma screening

• Biomarker research

• Capture-antibody comparison

• Assay feasibility studies

• Specificity evaluation

• Cross-reactivity studies

Protein and Peptide Interaction Research

Biotinylated proteins or peptides may be immobilized to study:

• Antibody–antigen interactions

• Protein–protein interactions

• Receptor–ligand binding

• Enzyme–substrate interactions

• Epitope recognition

• Inhibitor screening

• Drug candidate binding

• Affinity comparison

Nucleic Acid Capture and Detection

Biotinylated oligonucleotides, DNA, RNA, PCR products, and aptamers may be attached to SAPS3UM-10.

Potential applications include:

• Sequence-specific nucleic acid capture

• Hybridization assay development

• Mutation-detection research

• Genotyping research

• PCR-product capture

• Aptamer-based detection

• DNA–protein interaction studies

• RNA-binding studies

• Molecular assay development

Cell-Binding Research

When coated with an appropriate biotinylated antibody, receptor, ligand, or lectin, the microspheres may be evaluated for binding to cells or cell-surface targets.

Important parameters include:

• Ligand density

• Microsphere-to-cell ratio

• Incubation time

• Temperature

• Cell concentration

• Mixing method

• Washing conditions

• Cell viability

• Non-specific particle attachment

The synthetic microspheres are not biological cells and should not be used as a direct cell substitute without application-specific validation.

Multiplex Flow Cytometry

Different microsphere populations can potentially be distinguished by:

• Particle diameter

• Internal fluorescence color

• Internal fluorescence intensity

• Visible particle color

• Surface ligand

• Reporter fluorescence

For multiplex development, each population must remain distinguishable after ligand loading, blocking, sample incubation, washing, and storage.

The reporter fluorescence channel should also be separated from any internal microsphere coding signal.

Biosensor and Affinity Assay Research

SAPS3UM-10 may be evaluated in:

• Particle-based biosensors

• Microfluidic assays

• Affinity capture methods

• Imaging-based assays

• High-throughput screening

• Protein purification research

• Biomolecule enrichment studies

• Ligand-binding analysis

Compatible Biotinylated Biomolecules

Biotinylated Antibodies

Compatible antibody formats may include:

• Full-length IgG

• IgM

• Fab fragments

• F(ab′)₂ fragments

• Single-chain variable fragments

• Recombinant antibodies

• Single-domain antibodies

• Engineered antibody formats

Antibody activity after immobilization depends on the biotinylation method and biotin location.

Excessive random biotinylation may reduce antigen-binding activity or create variable antibody orientation.

Biotinylated Proteins

Examples include:

• Recombinant antigens

• Enzymes

• Cytokines

• Growth factors

• Receptors

• Lectins

• Binding proteins

• Fusion proteins

• Protein standards

Biotinylated Peptides

Potential uses include:

• Epitope mapping

• Antibody screening

• Receptor-binding studies

• Enzyme research

• Drug-screening assays

• Protein interaction studies

A spacer between the peptide and biotin may improve target accessibility in some applications.

Biotinylated Nucleic Acids

Compatible formats may include:

• Single-stranded DNA

• Double-stranded DNA

• RNA

• Oligonucleotide probes

• PCR amplicons

• Aptamers

• Modified nucleic acid probes

• Capture sequences

Biotinylated Small Molecules

Small biotinylated compounds may also be immobilized when the biotin group remains accessible to the streptavidin surface.

Spacer length and molecular orientation should be considered during assay design.

Recommended Biotinylated Ligand Loading Protocol

The following workflow is a general development starting point. It is not a fixed release protocol for every biomolecule.

1. Resuspend SAPS3UM-10

Allow the product to reach the recommended handling temperature.

Mix the vial using gentle inversion, rotation, or controlled vortexing until the microsphere suspension is homogeneous.

Because micron-sized microspheres may settle during storage, mix the product before every sampling step.

Avoid excessive foaming.

2. Calculate the Required Microsphere Amount

Determine the required microsphere quantity according to:

• Number of tests

• Microsphere amount per test

• Required number of flow cytometry events

• Expected target concentration

• Assay volume

• Ligand-binding capacity

• Number of washing steps

• Expected processing loss

Use lot-specific binding-capacity information when available.

3. Transfer the Microspheres

Transfer the required amount of SAPS3UM-10 to a clean, low-binding centrifuge tube or processing vessel.

Use clean pipette tips and avoid contaminating the original container.

4. Wash the Microspheres

Wash the particles using a binding buffer compatible with streptavidin and the biotinylated ligand.

A preliminary binding buffer may contain a neutral aqueous buffer and an appropriate salt concentration.

Avoid buffers or supplements containing free biotin during ligand loading.

Possible particle-recovery methods include:

• Centrifugation

• Membrane filtration

• Tangential-flow filtration

• Other validated solid–liquid separation methods

The required centrifugation conditions must be established experimentally for SAPS3UM-10.

5. Prepare the Biotinylated Ligand

Dilute the biotinylated antibody, protein, peptide, or nucleic acid in the selected binding buffer.

Important considerations include:

• Ligand concentration

• Biotinylation level

• Molecular purity

• Aggregate level

• Buffer additives

• Free biotin contamination

• Protein stability

• Nucleic acid stability

6. Add the Biotinylated Ligand

Combine the washed microspheres with the biotinylated ligand.

Use gentle mixing to maintain a uniform suspension during incubation.

Avoid mixing conditions that cause foaming, particle damage, or biomolecule denaturation.

7. Optimize the Incubation

Parameters to evaluate include:

• Microsphere concentration

• Ligand concentration

• Ligand-to-microsphere ratio

• Incubation time

• Incubation temperature

• Buffer pH

• Salt concentration

• Mixing speed

• Total reaction volume

Test several ligand concentrations rather than assuming that maximum ligand loading will provide the best assay result.

Excessive surface loading can create steric crowding and reduce target accessibility.

8. Remove Unbound Ligand

Separate and wash the microspheres to remove unbound biotinylated molecules.

Insufficient washing may increase background, while excessive washing may reduce particle recovery.

9. Block the Microspheres

Incubate the ligand-loaded microspheres with an application-compatible blocking reagent.

Potential blocking materials include:

• Bovine serum albumin

• Casein

• Fish gelatin

• Non-immune immunoglobulin

• Synthetic blocking polymers

• Commercial microsphere-blocking buffers

Blocking performance must be evaluated using both positive and negative samples.

10. Resuspend the Prepared Microspheres

Resuspend the coated and blocked particles in an appropriate assay or storage buffer.

Evaluate:

• Particle dispersion

• Ligand retention

• Binding activity

• Background signal

• Microsphere recovery

• Short-term stability

• Long-term stability

• Freeze–thaw sensitivity

• Microbial stability

Flow Cytometry Bead Assay Workflow

1. Prepare the Capture Microspheres

Load SAPS3UM-10 with the selected biotinylated capture molecule.

Wash and block the particles before sample testing.

2. Prepare Controls

Recommended controls may include:

• Acquisition-buffer blank

• Uncoated microsphere control

• Streptavidin microspheres without biotinylated ligand

• Ligand-loaded microspheres without sample

• Negative sample

• Positive sample

• Reporter-only control

• Isotype control

• Non-relevant biotinylated ligand control

• Single-color controls for multicolor experiments

3. Add the Test Sample

Combine the prepared microspheres with the sample.

Optimize:

• Sample volume

• Sample dilution

• Microsphere concentration

• Incubation time

• Incubation temperature

• Mixing method

• Target concentration range

• Matrix compatibility

4. Wash the Microspheres

Remove unbound sample components while maintaining acceptable microsphere recovery.

Record the number and volume of wash steps during method development.

5. Add the Fluorescent Reporter

Add a fluorescent detection antibody, secondary antibody, nucleic acid probe, or other reporter reagent.

The reporter fluorophore must be compatible with the lasers and detectors of the intended flow cytometer.

6. Incubate and Wash

Optimize reporter concentration and incubation time.

Remove unbound fluorescent reporter to reduce background signal.

7. Resuspend for Acquisition

Resuspend the final particles in a clean, low-background flow cytometry buffer.

Mix the particles immediately before acquisition.

8. Acquire Flow Cytometry Data

Collect enough microsphere events to support the intended statistical analysis.

Possible outputs include:

• Median fluorescence intensity

• Mean fluorescence intensity

• Percentage of positive microspheres

• Signal-to-background ratio

• Dose-response curve

• Assay precision

• Recovery

• Specificity

• Cross-reactivity

• Limit-of-detection research

9. Analyze the Data

Establish positive and negative regions using appropriate controls.

Do not define the positive threshold using the test sample alone.

Detection and Gating of 3µm Microspheres

Forward-Scatter and Side-Scatter Detection

The 3µm microsphere population may be located using forward scatter and side scatter on many conventional flow cytometers.

A preliminary FSC-versus-SSC plot can be used to identify the main particle population and exclude:

• Electronic noise

• Small debris

• Buffer particles

• Large aggregates

• Irregular events

The exact scatter position depends on the particle matrix, refractive index, instrument optics, laser configuration, and detector settings.

Fluorescence Detection

If SAPS3UM-10 does not contain an internal fluorescent dye, the microsphere population can still be measured using fluorescence from a bound reporter.

Possible plots include:

• FSC versus SSC

• FSC versus reporter fluorescence

• SSC versus reporter fluorescence

• Reporter fluorescence histogram

• Fluorescence area versus height

• Scatter area versus width

Singlet and Aggregate Analysis

Particle aggregates can produce higher scatter and fluorescence signals than individual particles.

Pulse geometry parameters may help distinguish singlets from doublets or larger aggregates.

Potential parameters include:

• Signal area

• Signal height

• Signal width

Trigger Selection

Possible acquisition triggers include:

• Forward scatter

• Side scatter

• Reporter fluorescence

• Internal microsphere fluorescence

• Combined gating strategies

The trigger should provide clear separation between microsphere events and background.

Particle Concentration

Run a dilution series during initial method development.

An excessively concentrated suspension may cause coincidence or swarm detection, in which multiple particles are recorded as one event.

Possible signs include:

• Concentration-dependent fluorescence shifts

• Increased apparent scatter

• Broad distributions

• Unexpected doublet populations

• Unstable event rates

• Reduced linearity after dilution

Recommended Method Records

Document:

• Flow cytometer model

• Laser configuration

• Detector filters

• Detector gain or voltage

• Scatter settings

• Trigger channel

• Trigger threshold

• Sample flow rate

• Microsphere dilution

• Buffer composition

• Acquisition time

• Number of collected events

• Analysis gates

• Product lot number

Blocking and Non-Specific Binding Control

Non-specific adsorption can increase negative-sample fluorescence and reduce assay sensitivity.

Potential causes include:

• Insufficient blocking

• Incompatible blocker

• Excess capture ligand

• Excess fluorescent reporter

• Inadequate washing

• Aggregated antibodies

• Hydrophobic sample components

• High sample protein concentration

• Particle aggregation

• Matrix interference

• Unstable conjugates

Screen Multiple Blocking Reagents

Evaluate more than one blocking formulation.

The best blocker should reduce negative-sample fluorescence while retaining the positive-sample signal.

Optimize Capture-Ligand Loading

More ligand is not always better.

Excessive ligand loading may:

• Increase reagent consumption

• Create steric crowding

• Reduce target accessibility

• Increase non-specific interactions

• Broaden assay variation

Titrate the Fluorescent Reporter

An excessive reporter concentration can increase background fluorescence.

Evaluate several reporter concentrations using positive and negative samples.

Optimize Washing Conditions

Important parameters include:

• Number of washes

• Wash-buffer composition

• Wash volume

• Mixing method

• Particle-recovery method

• Residual supernatant volume

Evaluate Detergents Carefully

A small amount of compatible detergent may improve particle dispersion and reduce non-specific adsorption.

Excessive detergent may affect biomolecule interactions or assay performance.

Avoid Free Biotin During Ligand Loading

Free biotin can occupy streptavidin-binding sites and reduce the amount of biotinylated ligand captured by the microspheres.

Review buffers, supplements, sample media, and blocking reagents for possible biotin content.

Comparison of 3µm and 1µm Streptavidin Microspheres

Both particle sizes can support flow cytometry and bead-based assay development, but they have different practical characteristics.

Choose SAPS3UM-10 When:

• Easier scatter detection is important.

• A conventional flow cytometer will be used.

• Clear particle gating is required.

• Micron-sized bead handling is preferred.

• Centrifugal recovery will be used.

• The project involves routine bead-based assays.

• Easier separation from small particulate background is desired.

Choose SAPS1UM-10 When:

• A higher particle number per unit mass is preferred.

• Smaller microspheres are required.

• Lower particle settling is important.

• The instrument can reliably detect 1µm particles.

• The assay uses small reaction volumes.

• A larger collective particle surface area may be beneficial.

The final selection should be based on assay performance rather than particle diameter alone.

Quality Control and Batch Consistency

For research reagent manufacturing and bulk purchasing, SAPS3UM-10 should be evaluated using agreed specifications.

Potential quality-control parameters include:

• Mean particle diameter

• Particle-size distribution

• Particle-size coefficient of variation

• Suspension appearance

• Solids content

• Streptavidin coating consistency

• Biotin-binding capacity

• Particle dispersion

• Aggregate level

• Particle recovery

• Background fluorescence

• Non-specific binding

• Microbial control

• Packaging integrity

• Storage stability

• Lot-to-lot consistency

Particle-Size Testing

Particle-size characterization may include:

• Mean diameter

• Median diameter

• Size distribution

• Coefficient of variation

• Microscopy images

• Instrument-specific characterization

The test method should be stated when reporting size results.

Biotin-Binding Capacity

Binding capacity should be determined using a defined biotinylated probe.

The result can be affected by:

• Probe molecular size

• Number of biotin groups

• Probe purity

• Incubation time

• Buffer composition

• Detection method

• Calculation basis

Binding-capacity values from different suppliers may not be directly comparable when different test probes or methods are used.

Flow Cytometry Quality Control

A flow cytometry-based QC method may evaluate:

• Main particle-population position

• Percentage of gated microspheres

• Reporter fluorescence after loading a standard probe

• Fluorescence distribution width

• Background separation

• Repeatability

• Aggregate population

Use the same flow cytometer and acquisition settings when comparing production lots.

Lot-Specific Documentation

Available documents may include:

• Certificate of Analysis

• Product specification

• Particle-size results

• Solids-content results

• Binding-capacity results

• Safety Data Sheet

• Handling instructions

• Storage recommendations

• Lot number

• Production date

Required release tests and acceptance limits should be confirmed before bulk manufacturing.

Bulk Manufacturing and Customization

Shanghai SanYu Biotechnology Co., Ltd. provides SHBC streptavidin microspheres for laboratory research, pilot development, repeated production, and bulk purchasing.

Research Sample Evaluation

Samples may be used to evaluate:

• Flow cytometry detection

• Particle dispersion

• Streptavidin activity

• Biotinylated ligand loading

• Non-specific binding

• Particle recovery

• Assay feasibility

• Instrument compatibility

Pilot-Scale Development

Pilot batches may support:

• Assay optimization

• Binding-capacity verification

• Stability studies

• Buffer selection

• Packaging evaluation

• Quality-control development

• Customer verification

• Process transfer

Bulk Production

Bulk manufacturing can be arranged after the technical specification and quality requirements have been confirmed.

Please provide:

• Required quantity

• Expected annual demand

• Preferred package size

• Intended application

• Required particle diameter

• Required solids content

• Required binding capacity

• Ligand type

• Buffer requirements

• Preservative restrictions

• Quality-control requirements

• Documentation requirements

• Delivery schedule

• Delivery destination

Custom Particle Diameter

Alternative particle diameters may be discussed according to the intended assay and technical feasibility.

Custom Streptavidin Coating

Project-specific streptavidin loading or binding-capacity targets may be evaluated.

Custom Fluorescence Coding

For multiplex flow cytometry projects, fluorescently encoded streptavidin microspheres may be discussed.

Potential options may include:

• Different excitation wavelengths

• Different emission wavelengths

• Multiple fluorescence colors

• Multiple fluorescence-intensity levels

• Customer-specific particle codes

Custom Concentration

Alternative solids concentrations may be discussed according to processing, packaging, and application requirements.

Custom Buffer and Preservative

Customer-specific buffer systems or preservative restrictions may be considered after compatibility and stability evaluation.

OEM and Private Label Supply

Available cooperation formats may include:

• OEM packaging

• Customer-specific labels

• Customer-specific catalog numbers

• Private-label supply

• Technical-document customization

• Bulk raw material supply

Handling and Storage Recommendations

Follow the final product label, technical data sheet, and lot-specific Certificate of Analysis.

General recommendations include:

• Store under the specified refrigerated conditions.

• Do not freeze unless freeze–thaw stability has been validated.

• Keep the container tightly closed.

• Store the vial upright.

• Mix the suspension thoroughly before sampling.

• Use clean pipette tips and low-binding tubes.

• Avoid contamination of the original product.

• Do not allow the microspheres to dry.

• Avoid repeated unnecessary temperature changes.

• Do not return diluted material to the original container.

• Record the product lot number and opening date.

Resuspension

Micron-sized microspheres may settle during storage.

Before use:

1. Allow the vial to reach the recommended handling temperature.

2. Gently invert or rotate the vial.

3. Apply controlled vortexing when necessary.

4. Confirm that the suspension is homogeneous.

5. Inspect for irreversible aggregates.

Avoid Freezing

Freezing may cause:

• Particle aggregation

• Loss of streptavidin activity

• Changes in suspension stability

• Reduced particle recovery

• Increased assay background

Avoid Drying

Do not allow the microsphere pellet to dry during washing or processing.

Drying may cause irreversible aggregation and reduced functional performance.

Protect Against Free Biotin

Avoid free biotin in buffers and reagents during biotinylated ligand loading.

Evaluate Prepared Microsphere Stability Separately

Ligand-loaded and blocked microspheres may have different stability from the original SAPS3UM-10 suspension.

Evaluate the stability of the final prepared reagent under the intended storage conditions.

Frequently Asked Questions

What is SAPS3UM-10?

SAPS3UM-10 is a 3µm streptavidin-coated microsphere suspension supplied at 1% solids for capturing biotinylated biomolecules in flow cytometry and bead-based assay research.

What is the SHBC brand?

SHBC is the microsphere and biotechnology material brand of Shanghai SanYu Biotechnology Co., Ltd.

What is the particle diameter?

The nominal particle diameter is 3µm.

The measured diameter and size distribution should be confirmed using lot-specific documentation.

What is the solids content?

SAPS3UM-10 is supplied at 1% solids.

Are SAPS3UM-10 microspheres magnetic?

SAPS3UM-10 should not be assumed to be magnetic unless magnetic properties are specifically stated in the technical specification.

For a magnetic streptavidin product, select a product specifically described as streptavidin magnetic beads.

Are the microspheres fluorescent?

The standard SAPS3UM-10 product should not be assumed to contain an internal fluorescent dye unless fluorescence is specifically stated.

Flow cytometry detection may use particle scatter or fluorescence from a bound reporter.

What can bind to SAPS3UM-10?

The streptavidin surface can capture biotinylated antibodies, antigens, proteins, peptides, oligonucleotides, DNA, RNA, aptamers, and other biotin-containing molecules.

Can an unmodified antibody bind directly?

An unmodified antibody will not specifically bind through the streptavidin–biotin interaction unless it is biotinylated or connected through another compatible binding reagent.

Is EDC/NHS activation required?

EDC/NHS activation is normally not required when loading a biotinylated molecule onto streptavidin-coated microspheres.

What is the biotin-binding capacity?

The binding capacity should be confirmed using the product specification or lot-specific Certificate of Analysis.

It should not be estimated from solids content alone.

Can SAPS3UM-10 be used for flow cytometry?

Yes. The 3µm particle diameter is suitable for evaluation in flow cytometry bead assays and particle-based research.

Can a conventional flow cytometer detect 3µm particles?

Many conventional flow cytometers can detect 3µm microspheres using suitable scatter settings.

Actual performance depends on instrument optics, laser configuration, detectors, thresholds, and buffers.

Can the product be used for sandwich immunoassays?

Yes. A biotinylated capture antibody can be immobilized on the microsphere, followed by target capture and detection with a fluorescent reporter antibody.

Can the product be used for nucleic acid detection?

Yes. Biotinylated oligonucleotides, DNA, RNA, PCR products, or aptamers may be immobilized for nucleic acid capture and hybridization research.

Can SAPS3UM-10 be used in multiplex assays?

Yes, provided that the SAPS3UM-10 population can be distinguished from the other particle populations.

Customized fluorescent coding may be required.

How should SAPS3UM-10 be washed?

The washing method depends on the particle matrix, density, buffer, volume, and required recovery.

Centrifugation or filtration methods may be evaluated.

Why is microsphere recovery low?

Possible causes include:

• Insufficient centrifugal force

• Short centrifugation time

• Particle loss during supernatant removal

• Adhesion to the tube surface

• Incompatible separation method

• Particle aggregation

• Excessive washing

How can non-specific binding be reduced?

Optimize the blocking reagent, ligand concentration, reporter concentration, washing conditions, detergent level, sample dilution, and incubation time.

Can buffers containing free biotin be used?

Free biotin may block streptavidin-binding sites and should generally be avoided during ligand loading.

Why do 3µm microspheres settle?

Micron-sized particles may settle during storage because of their size and density.

Mix the suspension thoroughly before every sampling step.

Should SAPS3UM-10 be diluted before flow cytometry?

Yes. Prepare a working dilution according to the required particle number and event rate.

A dilution series is recommended during method development.

Can the microspheres be frozen?

Freezing is generally not recommended unless freeze–thaw stability has been specifically validated.

Can the concentration be customized?

Alternative solids concentrations may be discussed according to project requirements and manufacturing feasibility.

Can the binding capacity be customized?

Project-specific streptavidin loading or binding-capacity targets may be evaluated.

Can fluorescent streptavidin microspheres be produced?

Fluorescent or encoded streptavidin microspheres may be discussed for qualified flow cytometry and multiplex assay projects.

Is bulk production available?

Yes. Shanghai SanYu Biotechnology Co., Ltd. supports samples, pilot batches, repeated orders, and bulk production.

What information is required for a quotation?

Please provide:

• Catalog number SAPS3UM-10

• Required quantity

• Annual purchasing forecast

• Preferred package size

• Intended application

• Flow cytometer model

• Type of biotinylated ligand

• Required binding capacity

• Required microsphere number per test

• Buffer restrictions

• Preservative restrictions

• Quality-control requirements

• Documentation requirements

• Delivery destination

Request a Sample or Bulk Quotation

SHBC SAPS3UM-10 3µm Streptavidin Microspheres provide a flexible particle platform for immobilizing biotinylated antibodies, proteins, peptides, oligonucleotides, DNA, RNA, aptamers, and other biotin-labeled biomolecules.

The product is suitable for:

• Flow cytometry bead assays

• Bead-based immunoassay development

• Biotinylated antibody immobilization

• Protein interaction studies

• Nucleic acid capture

• Hybridization assays

• Affinity binding research

• Multiplex flow cytometry development

• Research reagent manufacturing

SAPS3UM-10 provides:

• 3µm nominal particle diameter

• Streptavidin-functional surface

• 1% solids suspension

• Compatibility with biotinylated biomolecules

• Sample and pilot-batch supply

• Bulk manufacturing capability

• OEM and custom-development support

For sample evaluation or bulk purchasing, provide your intended application, required quantity, biotinylated ligand, desired binding capacity, flow cytometer configuration, packaging requirements, and quality-control specifications.

Product Name: 3µm Streptavidin Microspheres
Catalog Number: SAPS3UM-10
Brand: SHBC
Manufacturer: Shanghai SanYu Biotechnology Co., Ltd.
Nominal Particle Diameter: 3µm
Surface Modification: Streptavidin
Solids Content: 1%
Primary Application: Flow Cytometry and Bead-Assay Research
Supply Capability: Samples, Pilot Batches, and Bulk Production
Intended Use: Research Use Only. Not for diagnostic or therapeutic use.