5um Streptavidin Microspheres SAPS5UM-10 1%

5µm Streptavidin Microspheres for Flow Cytometry

SHBC SAPS5UM-10 Streptavidin Microspheres are 5µm 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 bead assays, particle-based immunoassay development, affinity binding research, nucleic acid capture, biomolecule interaction analysis, and research reagent manufacturing.

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

Quick Product Answer

SAPS5UM-10 is a 5µm streptavidin-coated microsphere suspension supplied at 1% solids. The streptavidin-functional surface captures biotinylated biomolecules and can be used to develop flow cytometry bead assays, sandwich immunoassays, affinity capture systems, nucleic acid hybridization assays, protein interaction studies, and multiplex particle-based research platforms.

Product Highlights

• Product name: 5µm Streptavidin Microspheres

• Catalog number: SAPS5UM-10

• Brand: SHBC

• Manufacturer: Shanghai SanYu Biotechnology Co., Ltd.

• Nominal particle diameter: 5µm

• 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 SAPS5UM-10 Streptavidin Microspheres?

SAPS5UM-10 consists of 5µm microspheres with streptavidin immobilized on the particle surface.

Streptavidin-coated microspheres provide a convenient solid phase for capturing biotinylated molecules. Researchers can attach a selected biotinylated antibody, protein, peptide, nucleic acid probe, aptamer, receptor, or other ligand without performing direct covalent activation of the microsphere surface.

After ligand immobilization, the prepared microspheres can be used to capture target molecules from a sample. Target binding can then be detected with a fluorescent antibody, fluorescent probe, secondary reagent, or other compatible reporter and analyzed by flow cytometry.

Potential biotinylated ligands include:

• Monoclonal and polyclonal antibodies

• Recombinant antibodies

• Antibody fragments

• Antigens

• Recombinant proteins

• Peptides

• Enzymes

• Receptors

• Lectins

• Oligonucleotide probes

• DNA probes

• RNA probes

• PCR products

• Aptamers

• Biotinylated small molecules

The 5µm particle diameter provides a micron-sized population that can generally be distinguished from small particulate background on many conventional flow cytometers.

Compared with smaller particles, 5µm microspheres may offer easier scatter detection, more convenient gating, and more practical particle recovery during washing. However, particle number per unit mass, settling behavior, binding capacity, and assay kinetics differ from those of smaller microspheres and should be evaluated for the intended application.

SAPS5UM-10 is supplied as a research raw material. It is not automatically a finished diagnostic reagent, certified calibration bead, absolute counting standard, fluorescent coding bead, or magnetic separation product.

SAPS5UM-10 Technical Specifications

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

• Particle material

• Measured mean particle diameter

• Particle-size range

• Particle-size distribution

• Particle-size coefficient of variation

• Streptavidin coating level

• Biotin-binding capacity

• Particle number concentration

• Suspension buffer

• Buffer pH

• Stabilizer or surfactant

• Preservative

• Package size

• Shelf life

• Storage conditions

Binding capacity should be reported with the test probe, testing method, calculation basis, and lot-specific result.

The 1% solids concentration alone cannot determine particle number concentration or available biotin-binding capacity.

How Streptavidin–Biotin Binding Works

Streptavidin is a biotin-binding protein. When a biotinylated ligand is mixed with SAPS5UM-10, the biotin group binds to available streptavidin sites on the microsphere surface.

The basic structure can be represented as:

Microsphere Surface – Streptavidin – Biotin – Capture Ligand

For a sandwich immunoassay, the structure may be:

Microsphere – Streptavidin – Biotinylated Capture Antibody – Target Antigen – Fluorescent Detection Antibody

The fluorescence associated with each microsphere can then be measured by flow cytometry.

Advantages of Streptavidin–Biotin Immobilization

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

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

• Antibodies, proteins, peptides and nucleic acid probes can be immobilized.

• Ligand loading can be performed under mild aqueous conditions.

• Capture molecules can be changed without redesigning the base particle.

• The system supports modular assay development.

• The platform may be used in single-target and multiplex research.

• Immobilized ligands can be combined with different fluorescent reporters.

Final performance depends on:

• Streptavidin activity

• Streptavidin coating density

• Biotinylation level

• Biotin accessibility

• Ligand molecular size

• Spacer length

• Surface crowding

• Buffer composition

• Incubation conditions

• Target concentration

• Sample matrix

Free biotin in the ligand solution, sample, buffer, or blocking formulation can occupy available streptavidin-binding sites and reduce ligand immobilization.

Why Choose 5µm Streptavidin Microspheres?

Clear Detection on Conventional Flow Cytometers

The 5µm particle diameter can provide a distinct forward-scatter and side-scatter population on many conventional flow cytometers.

This can make it easier to:

• Locate the microsphere population

• Establish a stable scatter gate

• Separate microspheres from small debris

• Confirm particle recovery

• Identify possible aggregates

• Evaluate doublets

• Measure reporter fluorescence

• Build repeatable acquisition templates

Actual detection depends on the particle material, refractive index, flow cytometer optics, detector settings, trigger selection, and sample buffer.

Practical Size for Bead-Based Assays

The 5µm size range is suitable for many particle-based flow cytometry research workflows.

The particles provide a physical surface for capture-ligand immobilization while remaining small enough for suspension-based reactions and individual-particle analysis.

Easier Particle Recovery

Micron-sized particles may be easier to recover by a validated centrifugation or membrane-based method than smaller particles.

Particle recovery still depends on:

• Particle density

• Particle material

• Centrifugal force

• Centrifugation time

• Processing volume

• Tube geometry

• Tube surface

• Buffer viscosity

• Surfactant concentration

• Number of washing steps

The separation method should be verified experimentally.

Suitable for Cell-Size-Range Studies

A 5µm microsphere may be evaluated as a synthetic micron-sized particle in cell-analysis and particle-interaction research.

However, synthetic microspheres do not reproduce the complete physical or biological properties of cells, including deformability, density, membrane composition, receptor mobility, or biological activity.

Flexible Ligand Selection

The same SAPS5UM-10 base particle can be combined with different biotinylated capture molecules, enabling multiple assays to be developed from one particle platform.

Supports Research-to-Production Scale-Up

The product can support:

• Initial feasibility testing

• Assay optimization

• Pilot-lot production

• Stability testing

• Packaging evaluation

• Batch-to-batch comparison

• OEM development

• Long-term bulk supply

Key Features and Benefits

5µm Nominal Particle Diameter

The micron-sized particles are suitable for flow cytometry gating, particle-based binding studies, immunoassay development, and affinity capture research.

Streptavidin-Functional Surface

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

1% Solids Suspension

SAPS5UM-10 is supplied at 1% solids and can be diluted according to the required particle number, assay volume, binding capacity, and flow cytometry event rate.

Simple Ligand Immobilization

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

Modular Assay Platform

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

Suitable for Fluorescent Reporter Detection

The particles can be combined with fluorescent antibodies, probes, secondary reagents, or other reporters for flow cytometry analysis.

Suitable for Singleplex and Multiplex Research

SAPS5UM-10 may be evaluated as one particle population in a multiplex flow cytometry system.

Bulk Manufacturing Capability

SHBC supports samples, pilot batches, repeat orders, custom production, and bulk supply.

Custom Development Options

Particle diameter, concentration, streptavidin loading, binding capacity, buffer, preservative, fluorescence coding, packaging, and release specifications may be discussed for qualified projects.

Applications in Flow Cytometry Research

Bead-Based Sandwich Immunoassays

SAPS5UM-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 remaining particle surface.

3. Incubating the particles with the sample.

4. Capturing the target analyte.

5. Adding a fluorescent detection antibody.

6. Removing 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

• Food-safety targets

• Research compounds

Competitive Assay Development

SAPS5UM-10 may also be evaluated in competitive binding formats.

Competitive assays can be considered for:

• Small molecules

• Haptens

• Peptides

• Drugs

• Toxins

• Hormones

• Targets with limited binding sites

The relationship between target concentration and fluorescence signal depends on the final assay design.

Biotinylated Antibody Immobilization

Biotinylated antibodies can be attached to SAPS5UM-10 for:

• Antigen detection

• Antibody screening

• Hybridoma screening

• Biomarker research

• Capture-antibody comparison

• Assay feasibility studies

• Specificity evaluation

• Cross-reactivity testing

• Affinity comparison

Protein and Peptide Interaction Research

Biotinylated proteins and peptides may be immobilized for:

• Antibody–antigen interaction studies

• Protein–protein binding

• Receptor–ligand research

• Epitope mapping

• Enzyme interaction studies

• Inhibitor screening

• Drug-candidate evaluation

• Binding-affinity comparison

Nucleic Acid Capture

Biotinylated oligonucleotides, DNA, RNA, PCR products, and aptamers may be attached to SAPS5UM-10.

Potential research applications include:

• Sequence-specific capture

• Hybridization assay development

• PCR-product detection

• Genotyping research

• Mutation-detection research

• Aptamer-based assays

• 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 particles may be evaluated for binding to cells or cell-surface targets.

Important parameters include:

• Capture-ligand density

• Microsphere-to-cell ratio

• Cell concentration

• Incubation temperature

• Incubation time

• Mixing method

• Washing conditions

• Cell viability

• Non-specific particle attachment

Multiplex Flow Cytometry

Different microsphere populations can potentially be distinguished using:

• Particle diameter

• Internal fluorescence color

• Internal fluorescence intensity

• Visible particle color

• Capture ligand

• Reporter fluorescence

For multiplex research, each particle population should remain distinguishable after ligand loading, blocking, sample incubation, reporter staining, washing, storage, and flow cytometry acquisition.

Affinity Capture and Screening

SAPS5UM-10 may also be evaluated in:

• Affinity binding assays

• Ligand screening

• Antibody screening

• High-throughput research

• Particle-based biosensors

• Microfluidic assays

• Biomolecule enrichment studies

• Imaging-based particle assays

Compatible Biotinylated Biomolecules

Biotinylated Antibodies

Compatible formats may include:

• Full-length IgG

• IgM

• Fab fragments

• F(ab′)₂ fragments

• Recombinant antibodies

• Single-chain variable fragments

• Single-domain antibodies

• Other engineered antibody formats

Antibody activity after immobilization depends on the biotinylation method, number of biotin groups, biotin location, spacer design, and protein stability.

Biotinylated Proteins

Potential examples include:

• Antigens

• Recombinant proteins

• Enzymes

• Cytokines

• Growth factors

• Receptors

• Lectins

• Fusion proteins

• Binding proteins

Biotinylated Peptides

Potential uses include:

• Epitope mapping

• Antibody screening

• Receptor-binding studies

• Enzyme research

• Drug-screening assays

• Protein interaction studies

A suitable spacer between the peptide and biotin may improve accessibility.

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 be attached when their biotin group remains accessible to the streptavidin surface.

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

Recommended Biotinylated Ligand Loading Protocol

The following procedure is a general starting point. Final conditions should be optimized for the actual biomolecule and application.

1. Resuspend SAPS5UM-10

Allow the suspension to reach the recommended handling temperature.

Mix by gentle inversion, rotation, or controlled vortexing until homogeneous.

Because 5µm particles may settle during storage, mix the suspension before every sampling step.

Avoid excessive foaming.

2. Calculate the Required Microsphere Amount

Determine the amount required according to:

• Number of assays

• Microsphere quantity per test

• Required flow cytometry event count

• Expected target concentration

• Assay volume

• Lot-specific binding capacity

• Number of washing steps

• Expected processing loss

Do not estimate ligand loading from solids content alone.

3. Transfer the Microspheres

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

Use clean pipette tips and avoid contaminating the original container.

4. Wash the Particles

Wash the microspheres with a buffer compatible with streptavidin and the selected biotinylated ligand.

Avoid buffers containing free biotin during ligand loading.

Potential recovery methods include:

• Centrifugation

• Membrane filtration

• Tangential-flow filtration

• Other validated solid–liquid separation methods

Suitable conditions should be established experimentally.

5. Prepare the Biotinylated Ligand

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

Review:

• Ligand concentration

• Biotinylation level

• Molecular purity

• Aggregate level

• Free biotin content

• Buffer additives

• Protein stability

• Nucleic acid stability

6. Add the Ligand

Combine the washed microspheres with the biotinylated ligand.

Maintain gentle mixing so that the particles remain uniformly suspended.

Avoid mixing conditions that cause excessive foam, particle aggregation, or biomolecule denaturation.

7. Optimize Ligand Loading

Evaluate:

• Microsphere concentration

• Ligand concentration

• Ligand-to-particle ratio

• Incubation time

• Incubation temperature

• Buffer pH

• Salt concentration

• Mixing speed

• Reaction volume

Maximum ligand loading does not always provide the best assay performance.

Excessive surface loading may increase steric crowding and reduce target accessibility.

8. Remove Unbound Ligand

Separate and wash the particles to remove unbound biotinylated molecules.

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

9. Block the Microspheres

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

Potential blockers include:

• Bovine serum albumin

• Casein

• Fish gelatin

• Non-immune immunoglobulin

• Synthetic blocking polymers

• Commercial microsphere-blocking buffers

Blocking performance should be evaluated using positive and negative samples.

10. Resuspend the Prepared Microspheres

Resuspend the coated and blocked particles in a suitable assay or storage buffer.

Evaluate:

• Particle dispersion

• Ligand retention

• Binding activity

• Non-specific binding

• Particle recovery

• Short-term stability

• Long-term stability

• Microbial stability

Flow Cytometry Bead Assay Workflow

1. Prepare Capture Microspheres

Load SAPS5UM-10 with the selected biotinylated capture molecule.

Wash and block the particles before testing samples.

2. Prepare Controls

Recommended controls may include:

• Acquisition-buffer blank

• Streptavidin microspheres without capture 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 Sample

Combine the prepared microspheres with the test sample.

Optimize:

• Sample volume

• Sample dilution

• Microsphere concentration

• Target concentration range

• Incubation time

• Incubation temperature

• Mixing method

• Sample matrix

4. Wash the Microspheres

Remove unbound sample components while maintaining acceptable microsphere recovery.

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

5. Add the Fluorescent Reporter

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

The selected fluorophore must be compatible with the laser and detector configuration of the intended flow cytometer.

6. Incubate and Wash

Optimize reporter concentration and incubation time.

Remove unbound reporter to reduce background fluorescence.

7. Resuspend for Acquisition

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

Mix immediately before flow cytometry testing.

8. Acquire Data

Collect enough microsphere events to support the intended analysis.

Possible analytical 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

• Detection-limit research

9. Analyze the Results

Establish positive and negative regions using appropriate controls.

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

Detection and Gating of 5µm Microspheres

Forward-Scatter and Side-Scatter Gating

The 5µm microsphere population can be evaluated using forward-scatter and side-scatter plots on many conventional flow cytometers.

A preliminary FSC-versus-SSC gate can help exclude:

• Electronic noise

• Small debris

• Buffer particles

• Large aggregates

• Irregular events

The measured scatter position depends on the particle matrix, refractive index, instrument optics, detector settings, and flow-cell design.

Reporter Fluorescence Detection

When SAPS5UM-10 does not contain an internal fluorescent dye, the particle population can still be analyzed through scatter and the fluorescence of a bound reporter.

Useful plots may include:

• FSC versus SSC

• FSC versus reporter fluorescence

• SSC versus reporter fluorescence

• Reporter fluorescence histogram

• Scatter area versus height

• Scatter area versus width

Singlet and Aggregate Analysis

Aggregates may produce higher scatter, fluorescence, or signal width than individual particles.

Pulse area, height, and width parameters may help distinguish single particles from doublets and larger aggregates.

Trigger Selection

Potential acquisition triggers include:

• Forward scatter

• Side scatter

• Reporter fluorescence

• Internal particle fluorescence when available

• Combined gating strategies

Particle Concentration

Test a dilution series during initial method development.

Excessively concentrated microspheres can produce coincident events in which multiple particles are measured as one event.

Possible indications include:

• Concentration-dependent signal shifts

• Increased apparent fluorescence

• Increased scatter

• Broad distributions

• Unexpected doublet populations

• Unstable event rates

Recommended Method Records

Record:

• Flow cytometer model

• Laser configuration

• Detector filters

• Detector voltage or gain

• 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 blocking reagent

• Excess capture ligand

• Excess fluorescent reporter

• Inadequate washing

• Aggregated antibodies

• Hydrophobic sample components

• High sample protein concentration

• Microsphere aggregation

• Matrix interference

Screen Multiple Blocking Reagents

Compare several blocking formulations.

The preferred blocker should reduce negative-sample fluorescence while maintaining the positive-sample signal.

Optimize Ligand Loading

More capture ligand is not always better.

Excessive ligand loading may:

• Increase reagent consumption

• Cause steric crowding

• Reduce target accessibility

• Increase non-specific interactions

• Broaden assay variability

Titrate the Reporter

Excess fluorescent reporter can increase background.

Test several reporter concentrations using positive and negative controls.

Optimize Washing

Evaluate:

• Number of wash steps

• Wash-buffer composition

• Wash volume

• Mixing method

• Separation method

• Residual supernatant volume

• Microsphere recovery

Evaluate Detergents Carefully

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

Excess detergent may interfere with biomolecule interactions or reporter binding.

Avoid Free Biotin

Free biotin in buffers, supplements, samples, or blocking reagents may occupy streptavidin-binding sites and reduce ligand loading.

Comparison of 5µm, 3µm and 1µm Streptavidin Microspheres

Choose SAPS5UM-10 When:

• Strong scatter visibility is important.

• A conventional flow cytometer will be used.

• Clear particle gating is required.

• Easier separation from small debris is preferred.

• Micron-sized bead handling is desired.

• Centrifugal recovery will be used.

• A cell-size-range particle platform is useful.

• Routine bead-based flow assays are being developed.

Choose SAPS3UM-10 When:

• A smaller micron-sized particle is preferred.

• A balance between particle number and scatter detection is required.

• Lower settling than 5µm particles is desirable.

• Routine flow cytometry detection is still required.

Choose SAPS1UM-10 When:

• A higher particle number per unit mass is preferred.

• Smaller reaction volumes are used.

• Lower settling behavior is important.

• The instrument can reliably detect 1µm particles.

• A larger collective surface area per unit mass may be beneficial.

Final particle-size selection should be based on assay performance rather than diameter alone.

Quality Control and Batch Consistency

Potential quality-control parameters for SAPS5UM-10 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 report:

• Mean diameter

• Median diameter

• Size range

• Size distribution

• Coefficient of variation

• Microscopy or instrumental characterization

The measurement method should be stated when reporting results.

Biotin-Binding Capacity

Binding capacity should be determined with a defined biotinylated probe.

The measured result depends on:

• Probe type

• Probe molecular size

• Number of biotin groups

• Probe purity

• Incubation conditions

• Buffer composition

• Detection method

• Calculation basis

Values obtained using different test probes or methods may not be directly comparable.

Flow Cytometry Quality Control

A flow cytometry QC procedure 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 consistent instrument settings when comparing production lots.

Lot-Specific Documentation

Available documentation 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 tests and acceptance criteria should be agreed upon before bulk manufacturing.

Bulk Manufacturing and Customization

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

Research Sample Evaluation

Samples may be evaluated for:

• 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 requirements and release specifications have been confirmed.

Please provide:

• Required quantity

• Expected annual demand

• Preferred package size

• Intended application

• Required particle diameter

• Required solids content

• Required binding capacity

• Biotinylated ligand type

• Buffer requirements

• Preservative restrictions

• Quality-control requirements

• Documentation requirements

• Delivery schedule

• Delivery destination

Custom Particle Diameter

Alternative particle sizes may be discussed according to application and technical feasibility.

Custom Streptavidin Loading

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

Custom Fluorescence Coding

Internally fluorescent or encoded streptavidin microspheres may be discussed for multiplex flow cytometry projects.

Potential options may include:

• Alternative excitation wavelengths

• Alternative emission wavelengths

• Different fluorescence colors

• Multiple fluorescence-intensity levels

• Customer-specific particle codes

Custom Buffer and Concentration

Alternative solids concentrations, buffer formulations, preservative systems, and packaging formats may be evaluated.

OEM and Private Label Supply

Cooperation formats may include:

• OEM packaging

• Customer-specific labels

• Private-label supply

• Customer-specific catalog numbers

• Bulk raw material supply

• Technical-document customization

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 thoroughly before sampling.

• Use clean pipette tips and low-binding tubes.

• Avoid contamination of the original suspension.

• 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

Because 5µm particles may settle during storage:

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

• Reduced streptavidin activity

• Changes in suspension stability

• Reduced particle recovery

• Increased assay background

Avoid Drying

Do not allow the microsphere pellet to dry during washing.

Drying may cause irreversible aggregation and reduced functional performance.

Protect Against Free Biotin

Avoid free biotin during biotinylated ligand immobilization.

Evaluate Prepared Reagent Stability

Ligand-loaded and blocked microspheres may have different stability from the original SAPS5UM-10 suspension.

Evaluate the prepared reagent under the intended storage, transport, and operating conditions.

Frequently Asked Questions

What is SAPS5UM-10?

SAPS5UM-10 is a 5µm 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 nominal particle diameter?

The nominal particle diameter is 5µm.

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

What is the solids content?

SAPS5UM-10 is supplied at 1% solids.

Are SAPS5UM-10 microspheres magnetic?

The product should not be assumed to be magnetic unless magnetic properties are specifically stated in the technical specification.

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

Are the microspheres fluorescent?

The standard product should not be assumed to contain an internal fluorescent dye unless fluorescence is specifically listed in the product specification.

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

What molecules can bind to SAPS5UM-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 attach through the streptavidin–biotin interaction unless it is biotinylated or linked through another compatible 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?

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

It should not be calculated from solids content alone.

Can SAPS5UM-10 be used in flow cytometry?

Yes. The 5µm particle diameter is suitable for evaluation in flow cytometry bead assays and particle-based research.

Can a conventional flow cytometer detect 5µm microspheres?

Many conventional flow cytometers can detect 5µm microspheres using suitable scatter settings.

Actual performance depends on the instrument optics, lasers, detectors, trigger settings, and sample buffer.

Can SAPS5UM-10 be used for sandwich immunoassays?

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

Can it be used for nucleic acid detection?

Yes. Biotinylated oligonucleotides, DNA, RNA, PCR products, and aptamers may be evaluated for immobilization and target capture.

Can SAPS5UM-10 be used in multiplex assays?

Yes, provided that the SAPS5UM-10 population can be distinguished from the other microsphere populations.

Customized fluorescence coding may be required.

How should the microspheres be washed?

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

Centrifugation or membrane-based methods may be evaluated.

Why is microsphere recovery low?

Possible causes include:

• Insufficient centrifugal force

• Short centrifugation time

• 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, wash conditions, detergent level, sample dilution, and incubation time.

Can buffers containing free biotin be used?

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

Why do the particles settle?

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

Mix the suspension thoroughly before every sampling step.

Should SAPS5UM-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 multiplex flow cytometry projects.

Is bulk production available?

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

What information is required for a quotation?

Please provide:

• Catalog number SAPS5UM-10

• Required quantity

• Expected annual purchasing volume

• Preferred package size

• Intended application

• Flow cytometer model

• Type of biotinylated ligand

• Required binding capacity

• Required microsphere quantity per test

• Buffer restrictions

• Preservative restrictions

• Quality-control requirements

• Documentation requirements

• Delivery destination

Request a Sample or Bulk Quotation

SHBC SAPS5UM-10 5µm 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 sandwich immunoassays

• Competitive binding assays

• Biotinylated antibody immobilization

• Protein interaction research

• Nucleic acid capture

• Hybridization assays

• Affinity binding studies

• Multiplex flow cytometry development

• Research reagent manufacturing

SAPS5UM-10 provides:

• 5µm 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 the intended application, required quantity, biotinylated ligand, desired binding capacity, flow cytometer configuration, packaging requirements, and quality-control specifications.

Product Name: 5µm Streptavidin Microspheres
Catalog Number: SAPS5UM-10
Brand: SHBC
Manufacturer: Shanghai SanYu Biotechnology Co., Ltd.
Nominal Particle Diameter: 5µm
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.