30um Streptavidin Microspheres SAPS30UM-10 1%

30µm Streptavidin Microspheres for Biological Research

SHBC SAPS30UM-10 Streptavidin Microspheres are 30µm surface-functionalized microspheres developed for immobilizing biotinylated antibodies, antigens, proteins, peptides, enzymes, receptors, oligonucleotides, DNA, RNA, aptamers, and other biotin-labeled molecules.

The product is supplied as a 1% solids suspension and is designed for biological assay development, biomolecule immobilization, affinity interaction research, microscopy, cell–particle interaction studies, nucleic acid capture, microfluidics, agglutination research, particle-based biosensors, and research reagent manufacturing.

The 30µm diameter provides a large individual-particle surface and makes the microspheres comparatively easy to observe and manipulate in microscopy and imaging-based systems. The large particle size may also support cell-size-range modeling, individual-particle analysis, size-coded assays, and biological research requiring clearly identifiable microspheres.

Shanghai SanYu Biotechnology Co., Ltd. supports research sample evaluation, pilot-scale development, repeated manufacturing, OEM cooperation, private-label projects, and bulk supply for biotechnology companies, universities, research institutes, reagent developers, instrument manufacturers, and biological research organizations.

Quick Product Answer

SAPS30UM-10 is a 30µm streptavidin-coated microsphere suspension supplied at 1% solids. Its streptavidin-functional surface captures biotinylated biomolecules for antibody and protein immobilization, nucleic acid capture, biological assays, microscopy, cell–particle interaction studies, microfluidics, agglutination research, and particle-based detection-system development.

Product Highlights

• Product name: 30µm Streptavidin Microspheres

• Catalog number: SAPS30UM-10

• Brand: SHBC

• Manufacturer: Shanghai SanYu Biotechnology Co., Ltd.

• Nominal particle diameter: 30µm

• Surface modification: Streptavidin

• Solids content: 1%

• Binding principle: Streptavidin–biotin affinity

• Physical form: Aqueous microsphere suspension

• Primary application: Biological research and bead-based assays

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

• Customization: Available according to technical feasibility

• Intended use: Research use only

What Are SAPS30UM-10 Streptavidin Microspheres?

SAPS30UM-10 consists of 30µm microspheres with streptavidin immobilized on the particle surface.

The streptavidin coating provides binding sites for biotinylated molecules. Researchers can attach a selected biotinylated antibody, protein, peptide, nucleic acid probe, aptamer, receptor, lectin, ligand, or other biomolecule without directly activating the microsphere surface with EDC/NHS chemistry.

After a biotinylated capture molecule has been immobilized, the functionalized particles can serve as a solid phase for:

• Target capture

• Biomolecule immobilization

• Antibody screening

• Protein interaction analysis

• Nucleic acid hybridization

• Cell-surface binding research

• Microscopy-based detection

• Particle-based biosensors

• Agglutination studies

• Microfluidic research

• Imaging-based biological assays

• Affinity capture experiments

Potential biotinylated capture molecules include:

• Monoclonal antibodies

• Polyclonal antibodies

• Recombinant antibodies

• Antibody fragments

• Antigens

• Recombinant proteins

• Peptides

• Enzymes

• Receptors

• Lectins

• Growth factors

• Oligonucleotide probes

• DNA probes

• RNA probes

• PCR products

• Aptamers

• Biotinylated small molecules

Streptavidin-coated microspheres are widely used as a matrix for immobilizing biotinylated antibodies, proteins and nucleic acid probes. The final performance depends on the streptavidin coating, ligand biotinylation, surface accessibility, buffer, mixing and washing conditions.

The 30µm particle diameter provides more physical surface per individual particle than smaller microspheres. However, at the same mass concentration, larger microspheres provide fewer individual particles than smaller microspheres.

SAPS30UM-10 is therefore particularly suitable when the project prioritizes:

• Large surface per individual particle

• Direct optical observation

• Individual-particle analysis

• Cell-size-range particle modeling

• Size-based particle differentiation

• Controlled particle manipulation

• Microscopy and imaging

• Microfluidic transport

• Large-particle agglutination

• Easy visual confirmation of particle recovery

SAPS30UM-10 is supplied as a research raw material. It should not automatically be described as a finished diagnostic reagent, certified particle standard, absolute counting bead, magnetic separation bead, or fluorescent coding bead unless those features are specifically included in the final technical specification.

SAPS30UM-10 Technical Specifications

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

• Particle matrix

• Mean particle diameter

• Particle-size range

• Particle-size distribution

• Particle-size coefficient of variation

• Particle morphology

• Particle density

• Streptavidin coating level

• Biotin-binding capacity

• Particle number concentration

• Suspension buffer

• Buffer pH

• Stabilizer or surfactant

• Preservative

• Recommended recovery method

• Package size

• Shelf life

• Storage conditions

Direct competitor pages commonly expose exact diameter, surface functionality, concentration, package size and technical documentation in the product specification area. The same information architecture should be used for SAPS30UM-10 once the corresponding SHBC test data are available.

Biotin-binding capacity should be reported together with:

• Type of biotinylated test probe

• Probe molecular weight

• Biotinylation level

• Binding buffer

• Incubation time

• Incubation temperature

• Washing procedure

• Detection method

• Calculation basis

• Lot-specific result

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

How Streptavidin–Biotin Binding Works

Streptavidin is a biotin-binding protein that enables stable, non-covalent attachment of biotinylated molecules to a microsphere surface.

When a biotinylated ligand is mixed with SAPS30UM-10, the biotin group binds to available streptavidin sites on the particle.

The general structure can be represented as:

Microsphere Surface – Streptavidin – Biotin – Capture Molecule

For an antibody-based sandwich assay, the structure may be:

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

The detection antibody may carry a fluorescent, enzymatic, colorimetric, chemiluminescent, or other measurable reporter.

Advantages of Streptavidin–Biotin Immobilization

• Direct EDC/NHS activation is normally unnecessary for loading a biotinylated ligand.

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

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

• Ligand loading can be conducted under relatively mild aqueous conditions.

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

• The system supports modular assay development.

• Ligand loading can be optimized separately from target detection.

• Different reporter systems can be used with the same capture particle.

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

Factors Affecting Binding Performance

Final binding and assay performance may be affected by:

• Streptavidin coating density

• Streptavidin activity

• Number of biotin groups per ligand

• Location of the biotin groups

• Biotin accessibility

• Spacer length

• Ligand molecular size

• Ligand purity

• Ligand aggregation

• Surface crowding

• Buffer composition

• Salt concentration

• Incubation time

• Incubation temperature

• Mixing method

• Particle settling

Free biotin can occupy available streptavidin sites and reduce capture-ligand loading. Biotinylated molecules should therefore be purified when residual free biotin or excess biotinylation reagent may be present.

Why Choose 30µm Streptavidin Microspheres?

Large Surface per Individual Particle

A 30µm microsphere provides a larger physical surface per individual particle than a 20µm, 10µm, 5µm, or 3µm microsphere.

This may be useful when:

• A large amount of capture molecule is required per individual particle

• Strong signal generation per particle is desired

• Individual particles will be analyzed separately

• Surface-binding distribution will be observed by microscopy

• A cell-size-range synthetic model is required

• Localized binding or surface patterning is being investigated

A larger particle does not necessarily provide greater total surface area per unit mass. Smaller particles normally provide more particles at the same mass concentration.

Excellent Microscopy Visibility

The 30µm diameter makes individual particles comparatively easy to locate using suitable optical microscopy.

Potential imaging methods include:

• Bright-field microscopy

• Phase-contrast microscopy

• Fluorescence microscopy

• Confocal microscopy

• Imaging flow cytometry

• Automated high-content imaging

Microscopy may be used to evaluate:

• Particle morphology

• Surface fluorescence

• Ligand distribution

• Aggregation

• Cell–particle interactions

• Particle recovery

• Size-based differentiation

• Microfluidic movement

Suitable for Cell-Size-Range Research

The 30µm particle diameter is within the size range of many large cells and cell-like biological structures.

Potential research directions include:

• Synthetic cell-model studies

• Cell-sized particle transport

• Cell–particle contact research

• Phagocytosis and uptake studies

• Cell-surface receptor binding

• Immune-cell interaction research

• Microfluidic cell-model testing

• Imaging-system development

Synthetic microspheres do not reproduce all optical, mechanical, chemical or biological properties of living cells. Suitability as a cell model must be validated for the intended project.

Clear Particle Identification

The large particle size allows SAPS30UM-10 to be separated visually from many small background particles and debris.

This can be useful in:

• Microscopy

• Automated imaging

• Particle counting

• Microfluidic sorting

• Agglutination analysis

• Size-coded assays

• Individual-particle tracking

Practical Recovery and Manipulation

Large particles may be recovered using an optimized centrifugation, filtration, sedimentation or particle-picking method.

The most appropriate method depends on:

• Particle material

• Particle density

• Processing volume

• Centrifugal force

• Centrifugation time

• Filter pore size

• Tube geometry

• Buffer viscosity

• Surfactant concentration

• Required particle recovery

Suitable for Size-Coded Multiplex Research

A 30µm population may be combined with smaller microsphere populations in research systems that distinguish particles by size.

Potential applications include:

• Multi-analyte assays

• Internal process controls

• Imaging-based multiplex assays

• Microfluidic sorting

• Particle-tracking experiments

• Multiple capture-ligand populations

Key Features and Benefits

30µm Nominal Particle Diameter

The large particle size supports direct observation, individual-particle analysis, size-based identification and cell-size-range biological research.

Streptavidin-Functional Surface

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

1% Solids Suspension

SAPS30UM-10 is supplied at 1% solids and can be diluted according to the required particle number, reaction volume, binding capacity and detection method.

Simple Ligand Immobilization

Biotinylated capture molecules can be attached without direct chemical activation of the microsphere surface by the end user.

Large Surface per Particle

Each 30µm microsphere provides a comparatively large physical surface for ligand immobilization and particle-associated signal generation.

Multiple Detection Platforms

The microspheres may be evaluated with:

• Optical microscopy

• Fluorescence microscopy

• Confocal microscopy

• Imaging flow cytometry

• Conventional flow cytometry where fluidics permit

• Microfluidic systems

• Plate-based imaging

• Particle-counting systems

• Colorimetric detection

• Fluorescent detection

• Agglutination imaging

Modular Biological Assay Platform

The same particle platform can be combined with different biotinylated capture molecules for different research projects.

Bulk Manufacturing Capability

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

Custom Development Options

Particle diameter, streptavidin loading, binding capacity, solids content, buffer, preservative, fluorescent coding, visible color, packaging and release specifications may be discussed for qualified projects.

Biological Research Applications

Bead-Based Immunoassay Development

SAPS30UM-10 may be used as the solid phase in sandwich, indirect, competitive or particle-agglutination research assays.

A typical sandwich assay may include:

1. Immobilization of a biotinylated capture antibody.

2. Blocking of the remaining particle surface.

3. Incubation with the test sample.

4. Capture of the target analyte.

5. Addition of a labeled detection antibody.

6. Removal of unbound reagents.

7. Measurement of particle-associated signal.

Potential research targets include:

• Antibodies

• Antigens

• Cytokines

• Hormones

• Growth factors

• Enzymes

• Biomarkers

• Pathogen-associated proteins

• Food-safety analytes

• Environmental targets

• Veterinary research targets

• Research compounds

Competitive Binding Assays

Competitive assay formats may be evaluated for:

• Small molecules

• Haptens

• Peptides

• Drugs

• Toxins

• Hormones

• Metabolites

• Targets with limited accessible binding sites

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

Antibody Immobilization and Screening

Biotinylated antibodies may be attached for:

• Antigen detection

• Antibody screening

• Hybridoma screening

• Specificity studies

• Cross-reactivity evaluation

• Affinity comparison

• Capture-antibody selection

• Assay feasibility testing

• Biomarker research

Protein and Peptide Interaction Research

Biotinylated proteins and peptides may be immobilized to investigate:

• Antibody–antigen interactions

• Protein–protein binding

• Receptor–ligand interactions

• Epitope recognition

• Enzyme–substrate binding

• Inhibitor screening

• Drug-candidate binding

• Protein-affinity comparison

Nucleic Acid Capture and Hybridization

Biotinylated oligonucleotides, DNA, RNA, PCR products and aptamers may be attached to SAPS30UM-10.

Potential applications include:

• Sequence-specific capture

• Hybridization assay development

• PCR-product capture

• Genotyping research

• Mutation-detection research

• Aptamer-based detection

• DNA–protein interaction analysis

• RNA-binding research

• Molecular assay development

Cell–Particle Interaction Research

When coated with an appropriate biotinylated antibody, receptor, lectin, ligand or peptide, SAPS30UM-10 may be evaluated for interaction with cells.

Potential research directions include:

• Cell-surface receptor recognition

• Cell adhesion

• Ligand-mediated cell binding

• Immune-cell interaction

• Cellular uptake

• Phagocytosis

• Particle internalization

• Cell sorting research

• Synthetic antigen-presenting particle research

Important variables include:

• Capture-ligand density

• Particle-to-cell ratio

• Cell concentration

• Incubation time

• Incubation temperature

• Mixing method

• Washing conditions

• Cell viability

• Particle aggregation

• Non-specific attachment

Microscopy and High-Content Imaging

The 30µm particles may support:

• Bright-field imaging

• Phase-contrast imaging

• Fluorescence imaging

• Confocal microscopy

• High-content screening

• Particle localization

• Cell–particle interaction imaging

• Surface-binding analysis

• Automated particle classification

Microfluidic Research

SAPS30UM-10 may be evaluated in:

• Particle transport studies

• Microchannel flow research

• Size-based separation

• Particle trapping

• Hydrodynamic focusing

• Imaging in microfluidic devices

• Cell-sized particle manipulation

• Device-performance testing

The narrowest channel, valve, filter and connector must be compatible with 30µm particles.

Agglutination Research

Large streptavidin microspheres may be evaluated in research methods where target binding or bridging molecules produce measurable particle clustering.

Agglutination may be analyzed through:

• Optical microscopy

• Automated imaging

• Light scattering

• Sedimentation patterns

• Particle-count changes

• Image-analysis algorithms

The relationship between aggregation and analyte concentration must be optimized experimentally.

Particle-Based Biosensors

SAPS30UM-10 may serve as a visible solid-phase carrier in:

• Optical biosensors

• Imaging-based biosensors

• Microfluidic biosensors

• Fluorescent particle assays

• Enzyme-linked particle assays

• Surface-binding studies

Compatible Biotinylated Biomolecules

Biotinylated Antibodies

Potential 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 activity after immobilization depends on:

• Biotinylation chemistry

• Number of biotin groups

• Location of the biotin groups

• Spacer length

• Protein purity

• Antibody aggregation

• Surface loading

• Storage conditions

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

• Protein interaction studies

• Drug-screening assays

A suitable spacer between biotin and the peptide may improve molecular 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 immobilized when their biotin groups remain accessible to the streptavidin surface.

Spacer design and molecular orientation should be considered during method development.

Recommended Biotinylated Ligand Loading Protocol

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

1. Resuspend SAPS30UM-10

Allow the suspension to reach the recommended handling temperature.

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

Because 30µm particles can settle quickly, mix the stock immediately before every sampling step.

During repeated dispensing, maintain gentle mixing or remix the suspension before each aliquot.

2. Calculate the Required Particle Amount

Determine the required quantity according to:

• Number of tests

• Number of particles required per test

• Surface required per reaction

• Reaction volume

• Expected target concentration

• Lot-specific binding capacity

• Number of wash steps

• Expected processing loss

Do not estimate ligand-loading capacity from the solids concentration alone.

3. Transfer the Microspheres

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

Use a pipette tip with an opening suitable for 30µm particles.

Avoid narrow tips that may restrict particle transfer or produce inconsistent particle numbers.

4. Wash the Microspheres

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

Avoid free biotin during ligand immobilization.

Potential recovery methods include:

• Centrifugation

• Membrane filtration

• Controlled sedimentation

• Cell-strainer-based recovery

• Other validated solid–liquid separation methods

The method should be established using the actual particle material, density, buffer, processing volume and required recovery.

5. Prepare the Biotinylated Ligand

Dilute the selected biomolecule in a compatible binding buffer.

Review:

• Ligand concentration

• Biotinylation level

• Molecular purity

• Aggregate level

• Free biotin content

• Residual biotinylation reagent

• Buffer additives

• Protein stability

• Nucleic acid stability

6. Add the Ligand

Combine the washed particles with the biotinylated ligand.

Use gentle rotation, rocking or controlled mixing to keep the microspheres suspended.

Avoid excessive vortexing, foaming and mechanical conditions that may damage 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

Continuous gentle mixing is especially important for 30µm particles because sedimentation may produce uneven 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 Particle Surface

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 particle-blocking buffers

The blocker should reduce negative-sample signal without substantially 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

• Redispersion

• Short-term stability

• Long-term stability

• Microbial stability

Recommended Biological Assay Workflow

1. Prepare Capture Microspheres

Load SAPS30UM-10 with the selected biotinylated capture molecule.

Wash and block the particles before sample testing.

2. Prepare Controls

Recommended controls may include:

• Assay-buffer blank

• Streptavidin microspheres without capture ligand

• Capture-ligand-loaded microspheres without target

• Negative sample

• Positive sample

• Reporter-only control

• Isotype control

• Non-relevant biotinylated ligand control

• Unlabeled target control

• Single-color controls when fluorescence is used

3. Add the Test Sample

Combine the prepared microspheres with the test sample.

Optimize:

• Sample volume

• Sample dilution

• Particle concentration

• Particles per reaction

• Target concentration range

• Incubation time

• Incubation temperature

• Mixing method

• Sample matrix

Maintain gentle mixing throughout the incubation.

4. Wash the Particles

Remove unbound sample components while maintaining acceptable recovery.

Record:

• Number of washes

• Wash-buffer composition

• Wash volume

• Separation method

• Residual supernatant volume

• Mixing procedure

5. Add the Detection Reagent

Add a fluorescent, enzymatic, colorimetric, chemiluminescent or other compatible reporter.

The selected detection system must match the intended assay platform.

6. Incubate and Wash

Optimize reporter concentration and incubation time.

Remove unbound detection reagent to reduce background.

7. Resuspend for Detection

Resuspend the particles in a clean detection buffer.

Mix immediately before transferring the sample to the instrument, slide, microplate or imaging chamber.

8. Measure the Signal

Potential analytical outputs include:

• Mean particle fluorescence

• Median particle fluorescence

• Percentage of positive particles

• Surface fluorescence distribution

• Signal-to-background ratio

• Particle-associated enzyme activity

• Color intensity

• Agglutination level

• Particle-count changes

• Dose-response curve

• Assay precision

• Recovery

• Specificity

• Cross-reactivity

9. Analyze the Results

Establish positive and negative thresholds using appropriate controls.

Do not define a positive result using the test sample alone.

Handling, Mixing and Sampling of 30µm Microspheres

Rapid Settling

The 30µm microspheres may settle more rapidly than smaller particles.

Settling can cause:

• Unequal particle concentrations

• Variation between aliquots

• Inconsistent ligand loading

• Different particle counts between reactions

• Uneven exposure to the sample

• Variable assay signals

• Reduced reproducibility

Maintaining a Uniform Suspension

Suitable mixing methods may include:

• Gentle inversion

• End-over-end rotation

• Slow orbital mixing

• Gentle rocking

• Controlled vortexing before sampling

• Intermittent pipette mixing

Avoid vigorous mixing that produces foam or damages protein reagents.

Consistent Pipetting

During repeated dispensing:

1. Mix the stock thoroughly.

2. Aspirate the required volume promptly.

3. Dispense the entire volume.

4. Remix before the next aliquot.

5. Use the same pipetting technique for all samples.

For large batches, a validated slow-mixing system can help maintain a consistent particle concentration during filling.

Pipette-Tip Selection

Use tips with an opening large enough for unrestricted particle movement.

Very narrow tips may:

• Retain particles

• Produce uneven particle numbers

• Promote aggregation

• Reduce delivery accuracy

• Increase variation between samples

Particle Recovery and Washing Methods

Centrifugation

Centrifugation may be used when the particle density and suspension formulation permit efficient recovery.

The minimum effective centrifugal force and time should be determined experimentally.

An ideal condition should provide:

• Acceptable particle recovery

• A manageable particle pellet

• Easy redispersion

• Minimal aggregation

• Limited biomolecule damage

Filtration

A membrane, mesh or cell strainer with a suitable pore size may be used for washing or recovery.

Confirm:

• Particle retention

• Low non-specific biomolecule adsorption

• Acceptable particle recovery

• Easy release from the membrane

• Compatibility with the processing volume

Controlled Sedimentation

Natural or accelerated sedimentation may be suitable for selected workflows.

Sedimentation-based recovery may reduce mechanical stress but can require longer processing times and careful control of supernatant removal.

Manual Particle Selection

In microscopy or single-particle projects, individual microspheres may be manipulated using:

• Micropipettes

• Microcapillaries

• Micromanipulation systems

• Optical or mechanical particle-picking devices

Magnetic Separation

SAPS30UM-10 should not be assumed to be magnetic.

Magnetic separation is only appropriate when the product specification explicitly states that the particles contain a magnetic component.

Microscopy, Flow Cytometry and Microfluidic Detection

Optical Microscopy

The 30µm particles can generally be observed using standard optical microscopy.

Potential uses include:

• Morphology evaluation

• Aggregate inspection

• Particle counting

• Surface-binding visualization

• Cell–particle interaction analysis

• Recovery assessment

• Size-distribution observation

Fluorescence Microscopy

When the particle carries a fluorescent reporter, internal dye or fluorescently labeled target, fluorescence microscopy may be used to evaluate:

• Surface signal

• Binding uniformity

• Positive and negative particles

• Cell–particle interactions

• Multiplex populations

• Reporter localization

Confocal Microscopy

Confocal imaging may help distinguish surface-associated fluorescence from fluorescence in the surrounding solution and may support three-dimensional analysis of particle-associated binding.

Flow Cytometry

SAPS30UM-10 may be evaluated by flow cytometry only when the instrument fluidics are compatible with 30µm particles.

Before testing, confirm:

• Sample tubing diameter

• Flow-cell dimensions

• Nozzle or orifice size

• Narrowest fluidic pathway

• Particle concentration

• Aggregate level

• Sample flow rate

• Detector range

Some conventional flow cytometers may not be suitable for particles of this size. Instrument compatibility should be confirmed before routine use.

Imaging Flow Cytometry

The large particle size may be well suited to compatible imaging flow cytometry platforms that combine morphological images with fluorescence measurement.

Microfluidic Systems

Before using SAPS30UM-10 in a microfluidic device, confirm that:

• Channels are sufficiently wide

• Constrictions can pass the particles

• Valves and connectors are compatible

• Filters will not retain the particles unintentionally

• The selected flow rate does not promote blockage

• Aggregation is adequately controlled

Blocking and Non-Specific Binding Control

Non-specific adsorption may increase background and reduce assay sensitivity.

Potential causes include:

• Inadequate blocking

• Incompatible blocking reagent

• Excess capture ligand

• Excess detection reagent

• 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 the negative-sample signal while maintaining target-specific binding.

Optimize Capture-Ligand Loading

Maximum ligand loading does not always produce maximum assay performance.

Excessive loading may:

• Cause steric crowding

• Reduce target accessibility

• Increase reagent consumption

• Increase non-specific interactions

• Increase assay variation

Titrate the Detection Reagent

Excess detection reagent may increase background.

Test several reporter concentrations using positive and negative controls.

Optimize Washing

Evaluate:

• Number of wash steps

• Wash-buffer composition

• Wash volume

• Separation method

• Mixing method

• Residual supernatant

• Particle recovery

Evaluate Detergents Carefully

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

Excessive detergent may interfere with biomolecule interactions or detection reagents.

Comparison of 30µm, 20µm and 10µm Microspheres

Choose SAPS30UM-10 When:

• Maximum surface per individual microsphere is preferred.

• Direct microscopy is a primary detection method.

• A large cell-size-range particle model is required.

• Individual-particle analysis is important.

• Clear size-based identification is needed.

• Microfluidic manipulation is being studied.

• Large-particle agglutination research is planned.

• Strong visual confirmation of recovery is useful.

Choose SAPS20UM-10 When:

• A large microsphere is required with somewhat easier fluidic compatibility.

• Microscopy and cell-size-range research are important.

• Lower settling than 30µm particles is preferred.

• A greater particle number per unit mass is required.

Choose SAPS10UM-10 When:

• Conventional flow cytometry is a primary detection method.

• More particles per unit mass are required.

• Lower settling is preferred.

• Smaller reaction volumes will be used.

• Easier fluidic compatibility is important.

The final particle size should be selected according to the biological application, detection platform, required particle number, ligand loading, settling behavior, recovery method and instrument compatibility.

Quality Control and Batch Consistency

Potential quality-control parameters for SAPS30UM-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 rate

• Redispersion performance

• Particle recovery

• Background signal

• 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

• Minimum and maximum size

• Size distribution

• Coefficient of variation

• Microscopy results

• Instrumental particle-size analysis

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

Biotin-Binding Capacity

Binding capacity should be measured using a defined biotinylated probe.

The result may be affected by:

• Probe type

• Molecular size

• Biotinylation level

• Probe purity

• Incubation conditions

• Buffer composition

• Washing procedure

• Detection method

• Calculation basis

Binding values obtained with different probes or test methods may not be directly comparable. Bangs Laboratories similarly reports lot-specific binding capacity through the Certificate of Analysis rather than relying only on nominal particle properties.

Functional Quality Control

A functional QC assay may evaluate:

• Binding of a standardized biotinylated probe

• Percentage of positive particles

• Signal distribution

• Background separation

• Particle recovery

• Aggregate percentage

• Repeatability

• Redispersion after storage

Sampling Consistency

Because 30µm particles settle relatively quickly, filling and sampling procedures should be validated.

Potential controls include:

• Continuous gentle mixing during filling

• Particle-count testing at the beginning, middle and end of filling

• Solids-content verification

• Visual homogeneity inspection

• Particle-count comparison between containers

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 enterprise bulk purchasing.

Research Sample Evaluation

Samples may be evaluated for:

• Particle morphology

• Particle-size distribution

• Particle dispersion

• Streptavidin activity

• Biotinylated ligand loading

• Non-specific binding

• Particle recovery

• Assay feasibility

• Microscopy compatibility

• Microfluidic compatibility

• Settling and redispersion

Pilot-Scale Development

Pilot batches may support:

• Assay optimization

• Binding-capacity verification

• Stability studies

• Buffer selection

• Preservative evaluation

• Packaging evaluation

• Filling-process development

• 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 biological 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 manufacturing feasibility.

Custom Streptavidin Loading

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

Custom Fluorescence or Color Coding

For imaging and multiplex research, fluorescently encoded or visibly colored streptavidin microspheres may be discussed.

Potential options may include:

• Alternative excitation wavelengths

• Alternative emission wavelengths

• Different fluorescence colors

• Multiple fluorescence intensities

• Visible particle colors

• Customer-specific coding systems

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

• Customized technical documents

• Customer-specific release specifications

Storage and Stability 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.

• Maintain the particles in suspension during processing.

• Use clean pipette tips and low-binding tubes.

• Avoid contamination of the original suspension.

• Do not allow the particles to dry.

• Avoid repeated unnecessary temperature changes.

• Do not return diluted material to the original container.

• Record the product lot number and opening date.

Technical guidance from established streptavidin-particle suppliers similarly recommends maintaining the particles in liquid, preventing drying and avoiding freezing.

Settling and Resuspension

Because SAPS30UM-10 contains large particles, settling may occur rapidly.

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 immediately before sampling.

6. Continue gentle mixing during repeated dispensing.

7. Inspect for irreversible aggregates.

Reversible settling does not necessarily indicate product failure.

Avoid Drying

Do not allow the particle pellet to dry during washing.

Drying may cause:

• Irreversible aggregation

• Reduced streptavidin activity

• Difficult redispersion

• Increased background

• Reduced particle recovery

Avoid Freezing

Freezing may cause:

• Particle aggregation

• Changes in suspension stability

• Reduced protein activity

• Reduced particle recovery

• Increased assay variability

Evaluate Prepared Reagent Stability

Biotinylated-ligand-loaded and blocked microspheres may have different stability from the original SAPS30UM-10 product.

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

Troubleshooting Guide

Weak Biotinylated Ligand Binding

Possible causes:

• Free biotin in the buffer

• Residual biotinylation reagent

• Low ligand biotinylation

• Inaccessible biotin groups

• Insufficient ligand concentration

• Inadequate incubation time

• Inactive streptavidin

• Incompatible buffer

• Particle settling during incubation

Recommended actions:

• Remove free biotin.

• Purify the biotinylated ligand.

• Verify the biotinylation level.

• Evaluate a suitable spacer.

• Maintain continuous gentle mixing.

• Increase ligand concentration gradually.

• Test a positive-control biotinylated ligand.

High Background Signal

Possible causes:

• Insufficient blocking

• Excess detection reagent

• Inadequate washing

• Non-specific reporter adsorption

• Sample-matrix interference

• Aggregated antibodies

• Excess capture-ligand loading

Recommended actions:

• Compare different blockers.

• Titrate the detection reagent.

• Optimize washing.

• Remove protein aggregates when appropriate.

• Dilute the sample.

• Reduce capture-ligand loading.

Unequal Particle Numbers Between Aliquots

Possible causes:

• Rapid particle settling

• Inadequate stock mixing

• Delay between mixing and sampling

• Narrow pipette-tip opening

• Inconsistent transfer technique

Recommended actions:

• Mix before every aliquot.

• Use an appropriate pipette tip.

• Maintain slow mixing during repeated dispensing.

• Standardize the sampling interval.

• Verify particle numbers during filling.

Particle Aggregation

Possible causes:

• Incompatible buffer

• Extreme pH

• High ionic strength

• Freezing

• Drying

• Excessive ligand loading

• Insufficient stabilizer

• Microbial contamination

Recommended actions:

• Evaluate buffer compatibility.

• Avoid freezing and drying.

• Optimize ligand loading.

• Use controlled gentle mixing.

• Review stabilizer and preservative requirements.

Low Particle Recovery

Possible causes:

• Loss during supernatant removal

• Adhesion to tubes

• Incorrect filter pore size

• Incomplete sedimentation

• Incomplete transfer

• Excessive washing

• Particle retention inside pipette tips

Recommended actions:

• Use low-binding tubes.

• Optimize separation conditions.

• Validate the filter or mesh.

• Mix before every transfer.

• Reduce unnecessary wash steps.

• Leave a controlled residual volume above the pellet.

Microfluidic Blockage

Possible causes:

• Channel dimensions too small

• Particle aggregation

• High particle concentration

• Narrow connectors

• Incompatible valves or filters

• Insufficient device flushing

Recommended actions:

• Confirm the minimum channel dimension.

• Reduce particle concentration.

• Remove aggregates before loading.

• Increase flow-path dimensions.

• Validate the complete device with plain 30µm particles first.

Frequently Asked Questions

What is SAPS30UM-10?

SAPS30UM-10 is a 30µm streptavidin-coated microsphere suspension supplied at 1% solids for capturing biotinylated biomolecules in biological research and particle-based assays.

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 30µm.

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

What is the solids content?

SAPS30UM-10 is supplied at 1% solids.

Are SAPS30UM-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 stated.

A fluorescently encoded version may be discussed as a custom product.

Which molecules can bind to SAPS30UM-10?

The streptavidin surface can capture biotinylated antibodies, antigens, proteins, peptides, enzymes, receptors, 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 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 estimated from solids content alone.

Why choose 30µm microspheres?

The 30µm particles provide a large surface per individual particle, excellent microscopy visibility, clear size-based identification and dimensions suitable for selected cell-size-range research.

Do 30µm particles provide more total surface area?

Each 30µm particle has more surface area than each smaller particle.

However, smaller particles normally provide more particles and greater collective surface area per unit mass.

Why do the particles settle quickly?

Large particles generally settle more quickly than smaller microspheres.

Mix the stock immediately before sampling and maintain gentle mixing during incubation.

Can SAPS30UM-10 be used for microscopy?

Yes. The particle size is suitable for evaluation by optical, fluorescence and confocal microscopy.

Can SAPS30UM-10 be used in flow cytometry?

It may be used only when the flow cytometer fluidics, nozzle, flow cell and sample pathway are compatible with 30µm particles.

Can SAPS30UM-10 be used as a cell model?

The 30µm diameter may be useful in cell-size-range particle research.

Synthetic microspheres do not reproduce all optical, mechanical, chemical or biological properties of living cells.

Can the microspheres be used for immunoassays?

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

Can the particles be used for nucleic acid capture?

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

Can SAPS30UM-10 be used in multiplex assays?

Yes, provided that the 30µm population can be distinguished from other microsphere populations.

Size coding, fluorescence coding or visible color coding may be considered.

How should the particles be washed?

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

Centrifugation, filtration, mesh-based recovery or controlled sedimentation may be evaluated.

How can non-specific binding be reduced?

Optimize the blocking reagent, capture-ligand concentration, detection-reagent concentration, washing 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 capture-ligand loading.

Should SAPS30UM-10 be diluted before use?

Yes. Prepare a working concentration according to the required particle number, reaction volume and detection method.

Can SAPS30UM-10 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 coating levels or binding-capacity targets may be evaluated.

Can fluorescent 30µm streptavidin microspheres be produced?

Fluorescently encoded or visibly colored 30µm streptavidin microspheres may be discussed for qualified imaging, microfluidic and multiplex 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 SAPS30UM-10

• Required quantity

• Expected annual purchasing volume

• Preferred package size

• Intended biological application

• Type of biotinylated ligand

• Required binding capacity

• Required particles per test

• Detection method

• Buffer restrictions

• Preservative restrictions

• Quality-control requirements

• Documentation requirements

• Delivery destination

Request a Sample or Bulk Quotation

SHBC SAPS30UM-10 30µm Streptavidin Microspheres provide a large, clearly identifiable particle platform for immobilizing biotinylated antibodies, proteins, peptides, enzymes, receptors, oligonucleotides, DNA, RNA, aptamers and other biotin-labeled molecules.

The product is suitable for:

• Biological assay development

• Bead-based immunoassays

• Antibody immobilization

• Protein interaction research

• Nucleic acid capture

• Hybridization assays

• Cell–particle interaction research

• Microscopy and imaging

• Microfluidic research

• Agglutination research

• Size-coded multiplex systems

• Particle-based biosensors

• Research reagent manufacturing

SAPS30UM-10 provides:

• 30µm nominal particle diameter

• Streptavidin-functional surface

• 1% solids suspension

• Large surface per individual particle

• Excellent microscopic visibility

• 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, detection platform, packaging requirements and quality-control specifications.

Product Name: 30µm Streptavidin Microspheres
Catalog Number: SAPS30UM-10
Brand: SHBC
Manufacturer: Shanghai SanYu Biotechnology Co., Ltd.
Nominal Particle Diameter: 30µm
Surface Modification: Streptavidin
Solids Content: 1%
Primary Application: Biological Research and Bead-Based Assays
Supply Capability: Samples, Pilot Batches and Bulk Production
Intended Use: Research Use Only. Not for diagnostic or therapeutic use.