10um Streptavidin Microspheres SAPS10UM-10 1%

10µm Streptavidin Microspheres for Flow Cytometry

SHBC SAPS10UM-10 Streptavidin Microspheres are 10µm surface-functionalized microspheres developed for immobilizing biotinylated antibodies, antigens, proteins, peptides, oligonucleotides, DNA, RNA, aptamers, receptors, and other biotin-labeled molecules.

The product is supplied as a 1% solids suspension and is intended for flow cytometry bead assays, particle-based immunoassay development, affinity binding research, nucleic acid capture, cell-interaction studies, biomolecule screening, and research reagent manufacturing.

The 10µm particle diameter produces a clearly detectable micron-sized population on many conventional flow cytometers. It can provide strong scatter separation, convenient particle gating, and a relatively large physical surface per individual microsphere.

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

Quick Product Answer

SAPS10UM-10 is a 10µm streptavidin-coated microsphere suspension supplied at 1% solids. Its streptavidin-functional surface captures biotinylated biomolecules for flow cytometry bead assays, sandwich immunoassays, affinity interaction studies, nucleic acid hybridization, cell-binding research, and particle-based detection system development.

Product Highlights

• Product name: 10µm Streptavidin Microspheres

• Catalog number: SAPS10UM-10

• Brand: SHBC

• Manufacturer: Shanghai SanYu Biotechnology Co., Ltd.

• Nominal particle diameter: 10µm

• 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 SAPS10UM-10 Streptavidin Microspheres?

SAPS10UM-10 consists of 10µm microspheres with streptavidin immobilized on the particle surface.

The streptavidin-functional surface provides binding sites for biotinylated molecules. Researchers can attach a selected biotinylated antibody, antigen, protein, peptide, nucleic acid probe, aptamer, receptor, ligand, or other biomolecule without directly activating the microsphere surface with carbodiimide chemistry.

After a biotinylated capture molecule has been loaded, the prepared microspheres can be used as a solid phase for:

• Target capture

• Fluorescent reporter detection

• Antibody screening

• Protein interaction studies

• Nucleic acid hybridization

• Cell-surface binding research

• Bead-based immunoassays

• Multiplex flow cytometry

• Particle-based biosensors

• Affinity assay development

Potential biotinylated molecules include:

• Monoclonal antibodies

• 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 10µm particle diameter falls within the general size range of many biological cells and large synthetic microparticles. This can make the microsphere population easy to identify using forward scatter and side scatter on many flow cytometers.

However, a synthetic microsphere does not reproduce all properties of a biological cell. Particle material, refractive index, density, rigidity, surface composition, and fluorescence behavior can differ substantially from cells.

SAPS10UM-10 is supplied as a research raw material. It should not automatically be described as a finished diagnostic reagent, certified calibration bead, absolute counting standard, magnetic separation bead, or fluorescent coding bead unless those features are specifically included in the technical specification.

SAPS10UM-10 Technical Specifications

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

• Particle material

• Mean particle diameter

• Particle-size range

• Particle-size distribution

• Particle-size coefficient of variation

• Particle morphology

• Streptavidin coating level

• Biotin-binding capacity

• Particle number concentration

• Suspension buffer

• Buffer pH

• Stabilizer or surfactant

• Preservative

• Package size

• Shelf life

• Storage conditions

Biotin-binding capacity should be reported together with:

• The type of biotinylated probe

• Probe molecular weight

• Biotinylation level

• Test buffer

• Incubation conditions

• Detection method

• Calculation basis

• Lot-specific result

The 1% solids value should not be used alone to calculate the number of particles per milliliter or the available biotin-binding capacity.

How Streptavidin–Biotin Binding Works

Streptavidin is a biotin-binding protein. When a biotinylated molecule is mixed with SAPS10UM-10, the biotin group interacts with available streptavidin sites on the microsphere surface.

The basic immobilization structure can be represented as:

Microsphere Surface – Streptavidin – Biotin – Capture Molecule

For a bead-based sandwich immunoassay, the assay structure may be:

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

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

Advantages of Streptavidin–Biotin Immobilization

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

• One microsphere platform can be used with different capture molecules.

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

• Ligand attachment can be performed under mild aqueous conditions.

• The capture molecule can be changed without redesigning the base microsphere.

• The system supports modular assay development.

• Ligand loading can be optimized separately from target detection.

• The platform can support single-target and multiplex research.

• Different fluorescent reporters can be combined with the same capture microsphere.

Factors Affecting Ligand Immobilization

Final ligand loading and biological activity can be affected by:

• Streptavidin coating density

• Streptavidin activity

• Number of biotin groups per ligand

• Location of biotin groups

• Accessibility of biotin

• Spacer length

• Ligand molecular size

• Ligand purity

• Surface crowding

• Buffer composition

• Incubation time

• Incubation temperature

• Mixing method

Excessive biotinylation may affect antibody or protein activity. Excessive ligand loading may also cause steric crowding and reduce target accessibility.

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

Why Choose 10µm Streptavidin Microspheres?

Clear Scatter Detection

The 10µm particle diameter can generate a clearly defined forward-scatter and side-scatter population on many conventional flow cytometers.

This may help researchers:

• Locate the microsphere population quickly

• Separate particles from small debris

• Establish stable scatter gates

• Confirm particle recovery

• Identify aggregates

• Evaluate singlets and doublets

• Measure reporter fluorescence

• Build standardized analysis templates

Actual scatter behavior depends on the particle material, refractive index, flow cytometer optics, detector settings, trigger selection, flow rate, and acquisition buffer.

Large Surface per Individual Microsphere

A 10µm microsphere has a larger physical surface per individual particle than a 5µm, 3µm, or 1µm microsphere.

This may be useful when:

• A relatively large amount of capture molecule is needed per particle

• Each microsphere must generate a strong reporter signal

• Imaging of individual microspheres is required

• Cell-sized particle models are being evaluated

• Particle recovery and manipulation are important

A larger surface per particle does not necessarily mean a higher total surface area per milligram. Smaller particles generally provide more particles and more collective surface area at the same mass concentration.

Suitable for Cell-Size-Range Research

The 10µm diameter is comparable to the dimensions of many cells and cell-like particles.

SAPS10UM-10 may therefore be evaluated in research involving:

• Cell-sized particle detection

• Flow cytometry instrument setup

• Particle–cell interactions

• Phagocytosis research

• Cell-surface receptor binding

• Synthetic cell-model studies

• Microfluidic cell-sized particle handling

The microspheres should not be considered equivalent to biological cells without application-specific validation.

Convenient Particle Recovery

Large micron-sized particles may be comparatively easy to recover using a validated centrifugation, filtration, or sedimentation process.

The required recovery method depends on:

• Particle material

• Particle density

• Sample volume

• Centrifugal force

• Centrifugation time

• Tube geometry

• Buffer viscosity

• Surfactant level

• Required recovery

• Number of wash steps

SAPS10UM-10 should not be assumed to be magnetic unless magnetic properties are explicitly stated in its specification.

Suitable for Microscopy

The 10µm size may make individual microspheres easier to visualize using compatible optical or fluorescence microscopy than smaller particles.

Microscopy can support:

• Particle morphology evaluation

• Aggregate detection

• Surface-binding studies

• Cell–particle interaction imaging

• Microfluidic tracking

• Particle recovery assessment

• Fluorescence localization studies

Research-to-Production Scale-Up

SAPS10UM-10 can support:

• Initial feasibility testing

• Assay optimization

• Pilot production

• Stability testing

• Packaging evaluation

• Quality-control development

• Batch-to-batch comparison

• OEM projects

• Long-term bulk supply

Key Features and Benefits

10µm Nominal Particle Diameter

The large micron-sized particles are suitable for flow cytometry detection, particle gating, imaging, bead-based assays, and cell-sized particle research.

Streptavidin-Functional Surface

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

1% Solids Suspension

The product is supplied at 1% solids and can be diluted according to the required particle number, assay volume, ligand capacity, and flow cytometry event rate.

Simple Ligand Immobilization

Biotinylated capture molecules can be loaded without direct carbodiimide activation of the particle surface by the end user.

Strong Flow Cytometry Visibility

The 10µm size can support clear scatter detection and convenient gating on many conventional flow cytometers.

Modular Assay Platform

The same base particle can be combined with different biotinylated capture molecules for different research targets.

Compatible with Fluorescent Reporter Detection

Binding events can be measured using fluorescent detection antibodies, secondary antibodies, nucleic acid probes, or other reporter reagents.

Suitable for Singleplex and Multiplex Research

SAPS10UM-10 may be evaluated as one distinguishable particle population in a multiplex flow cytometry platform.

Bulk Manufacturing Capability

SHBC supports samples, pilot batches, repeated orders, OEM cooperation, and bulk supply.

Custom Development Options

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

Applications in Flow Cytometry Research

Bead-Based Sandwich Immunoassays

SAPS10UM-10 can be evaluated as the solid phase in a flow cytometry sandwich immunoassay.

A typical workflow includes:

1. Immobilizing a biotinylated capture antibody.

2. Blocking the remaining microsphere surface.

3. Incubating the particles with the test sample.

4. Capturing the target analyte.

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-related proteins

• Environmental analytes

• Food-safety targets

• Veterinary research targets

• Research compounds

Competitive Binding Assays

SAPS10UM-10 may also be evaluated in competitive assay formats.

Competitive assays may be suitable for:

• Small molecules

• Haptens

• Peptides

• Drugs

• Toxins

• Hormones

• Metabolites

• Targets with one accessible binding site

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

Biotinylated Antibody Immobilization

Biotinylated antibodies may be immobilized for:

• Antigen detection

• Antibody screening

• Hybridoma screening

• Biomarker research

• Capture-antibody comparison

• Specificity studies

• Cross-reactivity evaluation

• Affinity comparison

• Assay feasibility testing

Protein and Peptide Interaction Studies

Biotinylated proteins or peptides may be immobilized to investigate:

• Antibody–antigen interactions

• Protein–protein interactions

• Receptor–ligand binding

• Epitope recognition

• Enzyme–substrate interactions

• Inhibitor screening

• Drug-candidate binding

• Binding-affinity comparison

Nucleic Acid Capture and Hybridization

Biotinylated oligonucleotides, DNA, RNA, PCR products, and aptamers may be attached to SAPS10UM-10.

Potential applications include:

• Sequence-specific nucleic acid capture

• Hybridization assay development

• PCR-product detection

• Mutation-detection research

• Genotyping research

• Aptamer-based detection

• DNA–protein interaction studies

• RNA-binding research

• Molecular assay development

Cell-Surface Binding Research

When coated with an appropriate biotinylated antibody, receptor, ligand, peptide, or lectin, SAPS10UM-10 may be evaluated for interaction with cells or cell-surface targets.

Important parameters include:

• Capture-ligand density

• Microsphere-to-cell ratio

• Cell concentration

• Incubation time

• Incubation temperature

• Mixing method

• Washing conditions

• Cell viability

• Non-specific particle attachment

• Aggregate formation

Phagocytosis and Particle-Uptake Research

The 10µm particles may be evaluated in particle-uptake or phagocytosis-related research when the size is compatible with the selected cell model.

Application-specific validation is required because particle material, coating, surface charge, ligand density, and aggregation can affect cellular interaction.

Multiplex Flow Cytometry

Different microsphere populations may potentially be distinguished by:

• Particle diameter

• Internal fluorescence color

• Internal fluorescence intensity

• Visible particle color

• Capture molecule

• Reporter fluorescence

For multiplex development, each particle population should remain distinguishable after:

• Ligand loading

• Blocking

• Sample incubation

• Reporter staining

• Washing

• Storage

• Flow cytometry acquisition

Imaging and Microfluidic Research

SAPS10UM-10 may also be evaluated in:

• Fluorescence microscopy

• Particle-tracking studies

• Microfluidic systems

• Cell-sized particle transport

• Surface-binding research

• Filtration studies

• Imaging-based biosensors

• Particle recovery experiments

Compatible Biotinylated Biomolecules

Biotinylated Antibodies

Potentially compatible formats include:

• Full-length IgG

• IgM

• Fab fragments

• F(ab′)₂ fragments

• Recombinant antibodies

• Single-chain variable fragments

• Single-domain antibodies

• Engineered antibody formats

Antibody performance after immobilization depends on the biotinylation method, biotin location, number of biotin groups, spacer design, protein purity, and surface loading.

Biotinylated Proteins

Potential 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 analysis

A spacer between biotin and the peptide may improve 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 be immobilized when the biotin group is 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. Final conditions should be optimized for the actual biomolecule and application.

1. Resuspend SAPS10UM-10

Allow the suspension to reach the recommended handling temperature.

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

Because 10µm particles may settle relatively quickly, mix the product immediately before removing each aliquot.

Avoid excessive foaming.

2. Calculate the Required Particle Amount

Determine the required amount according to:

• Number of assays

• Particles required per assay

• Required flow cytometry event count

• Assay volume

• Expected target concentration

• Lot-specific binding capacity

• Number of washing steps

• Expected processing loss

Do not calculate ligand-loading capacity from solids content alone.

3. Transfer the Microspheres

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

Use a pipette tip with an opening suitable for 10µm particles.

Mix the stock suspension before and during repeated sampling to prevent concentration differences caused by settling.

4. Wash the Microspheres

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

Avoid buffers containing free biotin during ligand immobilization.

Potential recovery methods include:

• Centrifugation

• Membrane filtration

• Controlled sedimentation

• Other validated solid–liquid separation methods

The separation method should be optimized for particle recovery, dispersion, and processing volume.

5. Prepare the Biotinylated Ligand

Dilute the antibody, protein, peptide, nucleic acid, or other ligand 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.

Use gentle mixing that maintains the particles in suspension without producing excessive foam or damaging the biomolecule.

7. Optimize the Incubation

Evaluate:

• Microsphere concentration

• Ligand concentration

• Ligand-to-particle ratio

• Incubation time

• Incubation temperature

• Buffer pH

• Salt concentration

• Mixing speed

• Reaction volume

Because 10µm microspheres may settle, continuous gentle mixing can help maintain uniform ligand exposure.

8. Remove Unbound Ligand

Separate and wash the particles to remove unbound biotinylated molecules.

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

9. Block the Microsphere Surface

Incubate the ligand-loaded particles 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

The selected blocker should reduce negative-sample fluorescence without significantly reducing target-specific binding.

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

• Settling behavior

• Short-term stability

• Long-term stability

• Microbial stability

Flow Cytometry Bead Assay Workflow

1. Prepare the Capture Microspheres

Load SAPS10UM-10 with the selected biotinylated capture molecule.

Wash and block the particles before testing samples.

2. Prepare Experimental Controls

Recommended controls may include:

• Acquisition-buffer blank

• Streptavidin microspheres without capture ligand

• Ligand-loaded particles 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

• Microspheres per test

• Target concentration range

• Incubation time

• Incubation temperature

• Mixing method

• Sample matrix

Maintain gentle mixing during incubation because 10µm microspheres may settle.

4. Wash the Microspheres

Remove unbound sample components while maintaining acceptable particle recovery.

Record the number, volume, and composition of wash steps.

5. Add the Fluorescent Reporter

Add a fluorescent detection antibody, secondary antibody, nucleic acid 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 flow cytometry buffer.

Mix immediately before loading the sample onto the instrument.

8. Acquire Flow Cytometry Data

Collect enough microsphere events to support the intended analysis.

Potential analytical outputs include:

• Median fluorescence intensity

• Mean fluorescence intensity

• Percentage of positive particles

• 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 using the test sample alone.

Detection and Gating of 10µm Microspheres

Forward-Scatter and Side-Scatter Detection

The 10µm microsphere population may generate relatively strong forward-scatter and side-scatter signals on many conventional flow cytometers.

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

• Electronic noise

• Small debris

• Buffer particles

• Large aggregates

• Irregular events

The scatter position depends on particle material, refractive index, instrument optics, detector settings, flow-cell design, and sample buffer.

Instrument Fluidics

Before testing, confirm that the instrument fluidics, flow cell, sample tubing, and nozzle configuration are suitable for 10µm particles.

The particles should remain substantially smaller than the narrowest fluidic pathway used during acquisition.

Reporter Fluorescence Detection

When SAPS10UM-10 does not contain an internal fluorescent dye, particle identification can use scatter together with fluorescence from 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 increased scatter, fluorescence, and pulse width.

Pulse geometry parameters may help distinguish single particles from doublets and larger aggregates.

Potential parameters include:

• Signal area

• Signal height

• Signal width

Trigger Selection

Potential acquisition triggers include:

• Forward scatter

• Side scatter

• Reporter fluorescence

• Internal particle fluorescence when available

• Combined gating approaches

Particle Concentration

Prepare a dilution series during method development.

Excessively concentrated microspheres may produce coincident events in which multiple particles are measured as a single event.

Possible indications include:

• Concentration-dependent fluorescence shifts

• Increased apparent scatter

• Broad signal distributions

• Unexpected doublet populations

• Unstable event rates

• Reduced linearity after dilution

Recommended Method Records

Document:

• Flow cytometer model

• Fluidic or nozzle configuration

• 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:

• Inadequate blocking

• Incompatible blocking reagent

• Excess capture ligand

• Excess fluorescent reporter

• Insufficient washing

• Aggregated antibodies

• Hydrophobic sample components

• High sample protein concentration

• Particle aggregation

• Sample-matrix interference

Screen Multiple Blocking Reagents

Compare several blocking formulations.

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

Optimize Capture-Ligand Loading

Maximum surface loading does not always provide maximum assay performance.

Excessive ligand loading may:

• Increase reagent consumption

• Cause steric crowding

• Reduce target accessibility

• Increase non-specific interactions

• Increase assay variation

Titrate the Reporter

Excess fluorescent reporter may increase background.

Test several reporter concentrations using positive and negative controls.

Optimize Washing Conditions

Evaluate:

• Number of washes

• Wash-buffer composition

• Wash volume

• Mixing method

• Separation method

• Residual supernatant volume

• Particle recovery

Evaluate Detergents Carefully

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

Excessive detergent may interfere with biomolecule interactions or reporter binding.

Avoid Free Biotin

Free biotin may occupy streptavidin-binding sites and reduce capture-ligand loading.

Review buffers, supplements, culture media, blocking reagents, and sample components for possible free biotin.

Comparison of 10µm, 5µm and 3µm Streptavidin Microspheres

Choose SAPS10UM-10 When:

• Strong scatter visibility is required.

• A large micron-sized particle is preferred.

• A cell-size-range synthetic particle is needed.

• Individual particle imaging is important.

• A large surface per particle is desirable.

• Easy separation from small debris is required.

• Routine conventional flow cytometry will be used.

• A clearly separated size-coded bead population is needed.

Choose SAPS5UM-10 When:

• A balance between strong scatter detection and particle number is desired.

• Lower settling than 10µm particles is preferred.

• A standard bead-based flow cytometry assay is being developed.

• Micron-sized particle recovery is required.

Choose SAPS3UM-10 When:

• A smaller micron-sized particle is preferred.

• A higher particle number per unit mass is useful.

• Lower settling behavior is important.

• Conventional flow cytometry detection is still required.

Final particle-size selection should be based on assay performance, instrument capability, ligand loading, settling behavior, washing recovery, and required particle number.

Quality Control and Batch Consistency

Potential quality-control parameters for SAPS10UM-10 include:

• Mean particle diameter

• Particle-size range

• Particle-size distribution

• Particle-size coefficient of variation

• Particle morphology

• Suspension appearance

• Solids content

• Streptavidin coating consistency

• Biotin-binding capacity

• Particle dispersion

• Aggregate level

• Settling and redispersion behavior

• 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 results

• Instrumental particle-size results

The test method should be stated when reporting particle-size data.

Biotin-Binding Capacity

Binding capacity should be measured using a defined biotinylated probe.

The measured value can be influenced by:

• Probe type

• Molecular size

• Number of biotin groups

• Probe purity

• Incubation conditions

• Buffer composition

• Detection method

• Calculation basis

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

Flow Cytometry Quality Control

A flow cytometry QC method may evaluate:

• Main particle-population position

• Percentage of events inside the main gate

• Reporter fluorescence after loading a standard probe

• Fluorescence distribution width

• Background separation

• Repeatability

• Aggregate population

• Singlet percentage

Use consistent instrument settings when comparing different 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 release 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

• Settling and redispersion behavior

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 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 diameters may be discussed according to the 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, surfactants, preservative systems, and packaging formats may be evaluated.

OEM and Private Label Supply

Available 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 the suspension 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.

Settling and Resuspension

Because SAPS10UM-10 contains 10µm particles, settling may be more noticeable than with smaller microspheres.

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. Mix again immediately before sampling.

6. Inspect for irreversible aggregates.

Normal reversible settling does not necessarily indicate product failure.

Maintain Suspension During Incubation

Use gentle rotation, rocking, or another validated mixing method during ligand loading and assay incubation.

Without mixing, the particles may settle and produce uneven exposure to capture molecules, samples, or reporter reagents.

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 particle pellet to dry during washing.

Drying may cause irreversible aggregation and loss of functional performance.

Evaluate Prepared Reagent Stability

Ligand-loaded and blocked microspheres may have different stability from the original SAPS10UM-10 suspension.

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

Troubleshooting Guide

Weak Binding of the Biotinylated Ligand

Possible causes:

• Free biotin in the buffer

• Low biotinylation level

• Inaccessible biotin groups

• Insufficient ligand concentration

• Insufficient incubation time

• Inactive streptavidin surface

• Incompatible buffer

• Excessive particle settling

Recommended actions:

• Remove free biotin from the ligand preparation.

• Verify the biotinylation level.

• Use a ligand with a suitable spacer.

• Increase ligand concentration gradually.

• Maintain gentle mixing.

• Evaluate a fresh microsphere lot and positive-control ligand.

High Background Fluorescence

Possible causes:

• Insufficient blocking

• Excess reporter reagent

• Insufficient washing

• Non-specific reporter adsorption

• Sample-matrix interference

• Aggregated detection antibodies

• Excess capture-ligand loading

Recommended actions:

• Compare several blockers.

• Titrate the fluorescent reporter.

• Increase or optimize washing.

• Centrifuge or filter aggregated protein reagents when appropriate.

• Dilute the sample.

• Reduce capture-ligand loading.

Broad Microsphere Population

Possible causes:

• Particle aggregates

• Coincident events

• Incomplete resuspension

• Excessive sample concentration

• Instrument instability

• Mixed singlet and doublet events

Recommended actions:

• Resuspend the particles thoroughly.

• Prepare a dilution series.

• Use pulse area, height and width for aggregate exclusion.

• Reduce the sample flow rate.

• Check the instrument with an appropriate control.

Low Particle Recovery

Possible causes:

• Inappropriate centrifugal conditions

• Loss during supernatant removal

• Particle adhesion to the tube

• Excessive washing

• Incorrect filtration membrane

• Incomplete transfer

• Particle settling during pipetting

Recommended actions:

• Optimize centrifugal force and time.

• Use low-binding tubes.

• Leave a controlled residual volume above the pellet.

• Mix before each transfer.

• Reduce unnecessary wash steps.

• Validate the selected separation method.

Inconsistent Results Between Replicates

Possible causes:

• Rapid particle settling

• Unequal sampling from the stock

• Inconsistent mixing

• Variation in incubation time

• Variation in washing

• Different event counts

• Instrument-setting changes

Recommended actions:

• Mix the stock immediately before every aliquot.

• Maintain particles in suspension during incubation.

• Standardize all timing and wash steps.

• Record and lock instrument settings.

• Collect a consistent number of events.

Frequently Asked Questions

What is SAPS10UM-10?

SAPS10UM-10 is a 10µm 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 10µm.

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

What is the solids content?

SAPS10UM-10 is supplied at 1% solids.

Are SAPS10UM-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 SAPS10UM-10 product should not be assumed to contain an internal fluorescent dye unless fluorescence is specifically stated.

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

Which molecules can bind to SAPS10UM-10?

The streptavidin surface can capture biotinylated antibodies, antigens, proteins, peptides, oligonucleotides, DNA, RNA, aptamers, receptors, 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 connected 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 SAPS10UM-10 be used in flow cytometry?

Yes. The 10µm particle diameter is suitable for evaluation in flow cytometry bead assays and particle-based research.

Can a conventional flow cytometer detect 10µm particles?

Many conventional flow cytometers can detect 10µm microspheres using suitable scatter settings.

Confirm that the instrument fluidics and flow-cell configuration are compatible with the particle size.

Why choose 10µm instead of 5µm particles?

The 10µm particles generally provide stronger scatter visibility and a larger physical surface per individual microsphere.

The 5µm particles provide more particles per unit mass and may settle more slowly.

Can SAPS10UM-10 be used as a cell model?

The 10µm size may be relevant for cell-size-range particle research.

However, synthetic microspheres do not reproduce all optical, mechanical, surface, or biological properties of cells.

Can it 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 SAPS10UM-10 be used in multiplex assays?

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

Customized fluorescence coding may also be considered.

How should the microspheres be washed?

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

Centrifugation, filtration, or controlled sedimentation may be evaluated.

Why do the particles settle quickly?

Large micron-sized particles may settle faster than smaller microspheres because of their size and density.

Mix the suspension before sampling and maintain gentle mixing during incubation.

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.

Should SAPS10UM-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 SAPS10UM-10

• Required quantity

• Expected annual purchasing volume

• 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 SAPS10UM-10 10µm Streptavidin Microspheres provide a large, clearly detectable particle platform for immobilizing biotinylated antibodies, proteins, peptides, oligonucleotides, DNA, RNA, aptamers, receptors, and other biotin-labeled molecules.

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

• Cell-surface binding research

• Phagocytosis-related research

• Multiplex flow cytometry

• Imaging and microfluidic studies

• Research reagent manufacturing

SAPS10UM-10 provides:

• 10µm nominal particle diameter

• Streptavidin-functional surface

• 1% solids suspension

• Clear flow cytometry scatter detection

• 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: 10µm Streptavidin Microspheres
Catalog Number: SAPS10UM-10
Brand: SHBC
Manufacturer: Shanghai SanYu Biotechnology Co., Ltd.
Nominal Particle Diameter: 10µm
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.