Product Category
What Are Blue Carboxyl Particles?
Blue Carboxyl Particles, also known as Blue Carboxyl Microspheres, Blue Latex Particles, or Carboxylated Blue Polystyrene Microspheres, are visibly colored polymer microspheres functionalized with carboxyl (-COOH) groups on their surface.
The blue color provides a clear visual signal, while the surface carboxyl groups allow antibodies, antigens, proteins, peptides and other biomolecules to be covalently immobilized onto the particle surface. This combination makes blue carboxyl microspheres particularly useful as colored labels for lateral flow immunoassays (LFIA), immunochromatographic test strips, POCT assay development and other IVD applications.
SHBC supplies blue carboxyl particles with controlled particle sizes and stable aqueous dispersion for diagnostic assay developers, research laboratories and IVD reagent manufacturers. Our current standard blue carboxyl microsphere range includes 100 nm, 200 nm and 300 nm particles with 4% solids, providing different options for assay development and optimization.
Blue Carboxyl Microspheres Available from SHBC
Product | Particle Size | Solid Content | Surface Group | Typical Application |
|---|---|---|---|---|
CAB100-10 | 100 nm | 4% | Carboxyl (-COOH) | LFIA / IVD Assay Development |
CAB200-10 | 200 nm | 4% | Carboxyl (-COOH) | Lateral Flow Test Development |
CAB300-10 | 300 nm | 4% | Carboxyl (-COOH) | Colored Latex Labeling for LFIA |
Particle size is an important parameter during lateral flow assay development. Different particle sizes can affect migration behavior, visual signal, conjugation conditions and overall assay performance. Developers can evaluate multiple particle sizes during assay optimization to identify the most suitable formulation for a specific target and membrane system.
Key Features of Blue Carboxyl Microspheres
Strong Visible Blue Signal
Blue colored microspheres provide an easily recognizable optical signal without requiring fluorescence excitation equipment. They can therefore be used as visual labels in rapid diagnostic assays where results are interpreted directly by the eye or with an optical reader.
Carboxyl-Functionalized Surface
Carboxyl (-COOH) groups on the microsphere surface provide reactive sites for biomolecule immobilization. Using commonly applied carbodiimide coupling chemistry, antibodies, antigens and other molecules containing primary amine groups can be covalently attached to the particle surface.
Controlled Particle Size
Consistent particle size is important for reproducible migration and signal formation in particle-based diagnostic systems. SHBC offers defined 100 nm, 200 nm and 300 nm blue carboxyl particles to support assay screening and optimization.
Designed for IVD and POCT Development
Blue carboxyl latex particles can serve as functional colored labels in immunochromatographic assays and other particle-based diagnostic platforms, making them suitable for diagnostic reagent developers, rapid test manufacturers and research laboratories.
Blue Carboxyl Particles for Lateral Flow Immunoassays
One of the primary applications of blue carboxyl microspheres is lateral flow immunoassay development. In an LFIA system, antibodies, antigens or other recognition molecules can be conjugated onto the surface of the blue particles. When the target analyte is present, the particle conjugates migrate through the membrane and participate in specific recognition reactions at the test or control line.
Because the particles are visibly blue, accumulation at the capture line generates a colored signal that can be observed directly or analyzed by an optical reader.
Blue latex particles may be considered for both qualitative and semi-quantitative lateral flow assay development, depending on the assay design, recognition system and detection method.
Typical lateral flow applications may include:
Infectious disease rapid tests
Veterinary diagnostic tests
Food safety testing
Environmental testing
Biomarker detection
Antigen detection
Antibody detection
Research-use immunochromatographic assays
POCT assay development
Multiplex colored particle assay development
How Are Antibodies Coupled to Blue Carboxyl Microspheres?
The carboxyl groups on blue carboxyl particles can be used for covalent biomolecule immobilization through EDC/NHS coupling chemistry.
In a typical conjugation process, surface carboxyl groups are first activated using EDC, often together with NHS or sulfo-NHS. The activated groups can then react with primary amine groups on antibodies, proteins or other biomolecules to form stable amide bonds.
A typical development workflow may include:
Prepare and disperse the blue carboxyl microspheres.
Activate the surface carboxyl groups using EDC/NHS chemistry.
Add the antibody, antigen or other amine-containing biomolecule.
Allow the coupling reaction to proceed under optimized conditions.
Block remaining reactive sites when required.
Wash or purify the conjugated particles.
Resuspend the conjugate in an appropriate storage or running buffer.
Evaluate the conjugate in the target lateral flow assay.
Actual coupling conditions should be optimized for the biomolecule, particle size, buffer composition, pH, desired surface loading and final assay format.
How to Choose Blue Carboxyl Particle Size
There is no single particle size that is optimal for every diagnostic assay. Particle selection should be evaluated together with membrane type, analyte concentration, antibody affinity, conjugate loading, migration speed and required visual signal.
100 nm Blue Carboxyl Microspheres
100 nm particles provide a relatively small particle format and can be evaluated when good dispersion and smooth membrane migration are important during lateral flow assay development.
200 nm Blue Carboxyl Microspheres
200 nm blue carboxyl particles provide an intermediate particle size and are a practical starting point for many colored latex labeling experiments and LFIA optimization projects.
300 nm Blue Carboxyl Microspheres
300 nm particles provide a larger colored particle format and can be screened when stronger visible particle accumulation is desired. Migration and membrane compatibility should be evaluated as part of assay optimization.
Applications of Blue Carboxylated Polystyrene Microspheres
Blue carboxylated microspheres are versatile functional particles used in a range of biological and diagnostic research applications.
Lateral Flow Test Strips
Blue latex microspheres can be conjugated with recognition molecules and used as visible labels on immunochromatographic test strips.
Antibody and Protein Immobilization
Surface carboxyl groups provide sites for covalent conjugation of antibodies, antigens, proteins, peptides and other amine-containing molecules.
Agglutination Assays
Colored functional latex particles can also be evaluated in particle agglutination systems where visible particle aggregation is used as part of the detection principle.
Multiplex Assay Development
Different colored microspheres can help distinguish multiple particle populations within a diagnostic platform. Blue particles may therefore be combined with other colored particle systems when developing multiplex or multi-analyte assay concepts.
Diagnostic Assay Research
Blue carboxyl microspheres are also useful for proof-of-concept studies, conjugation optimization, membrane screening and other particle-based assay development work.
Blue Latex Particles vs. Other Colored Microspheres
The selection of a colored microsphere should depend on the detection platform and assay design. Blue particles provide a clearly distinguishable visible color and can be particularly useful when a blue optical signal is preferred or when different colors are required to distinguish multiple detection channels.
SHBC also supplies other colored and fluorescent microsphere platforms, allowing assay developers to evaluate different particle colors, particle sizes and signal technologies according to their diagnostic requirements.
Blue Carboxyl Microspheres for IVD and POCT Manufacturers
For diagnostic manufacturers, the selection of microsphere raw materials can directly influence conjugation development, membrane migration, signal appearance and assay reproducibility. Particle size, surface chemistry, solid concentration and dispersion characteristics should therefore be considered together when selecting colored latex microspheres.
SHBC provides blue carboxyl particles for IVD reagent development, POCT product development, lateral flow assay research and diagnostic manufacturing. Standard particle sizes can be used for initial screening, while customized microsphere requirements can be discussed according to specific assay development needs.
Why Choose SHBC Blue Carboxyl Particles?
Multiple Particle Sizes: Standard 100 nm, 200 nm and 300 nm options are available.
Carboxyl Functional Surface: Suitable for covalent immobilization of antibodies, antigens and proteins.
Visible Blue Signal: Designed for colored particle-based diagnostic applications.
4% Solid Content: Current standard CAB series products are supplied at 4% solids.
IVD & POCT Applications: Suitable for lateral flow and immunochromatographic assay development.
Microsphere Manufacturing Capability: SHBC supplies polymer microspheres, colored microspheres, fluorescent microspheres and magnetic bead platforms.
Customization Support: Custom particle requirements can be discussed for assay development and manufacturing projects.
Frequently Asked Questions About Blue Carboxyl Particles
What are blue carboxyl particles used for?
Blue carboxyl particles are mainly used as visible functional labels in lateral flow immunoassays, immunochromatographic test strips, antibody conjugation, protein immobilization, agglutination assays and other IVD or POCT assay development applications.
What is the surface functional group of blue carboxyl microspheres?
The particle surface contains carboxyl (-COOH) functional groups. These groups can be activated for covalent coupling with antibodies, proteins, antigens and other amine-containing biomolecules.
Can blue carboxyl microspheres be used for lateral flow assays?
Yes. Blue carboxyl microspheres are suitable for lateral flow assay development because they combine a visible blue signal with a functional surface for biomolecule conjugation.
What particle sizes are available?
SHBC currently offers standard blue carboxyl microspheres in 100 nm, 200 nm and 300 nm particle sizes with 4% solid content. Contact SHBC for other particle or customization requirements.
How are antibodies attached to blue carboxyl particles?
Antibodies can be covalently coupled to the carboxyl-functionalized surface using EDC/NHS chemistry. The activated carboxyl groups react with primary amines on the antibody to form stable amide bonds.
Which size should I choose for a lateral flow assay?
Particle size should be selected experimentally. 100 nm, 200 nm and 300 nm blue particles can be screened during assay development because particle size may influence conjugation, migration, membrane compatibility and visible signal generation.
Are blue carboxyl particles the same as fluorescent microspheres?
No. Blue carboxyl particles are designed primarily to provide a visible colored signal. Fluorescent microspheres generate fluorescence under appropriate excitation and are normally selected when fluorescence-based detection or higher-sensitivity optical reading is required.
Can SHBC provide customized blue microspheres?
SHBC supports microsphere development and customization for diagnostic and research applications. Customers with requirements for specific particle sizes, surface chemistry, concentrations or assay applications can contact our technical team to discuss the appropriate microsphere solution.
Request Blue Carboxyl Microspheres for Your Assay Development
If you are developing a lateral flow test, POCT diagnostic product or other particle-based assay, SHBC can help you evaluate suitable Blue Carboxyl Microspheres based on particle size, surface functionality and application requirements.
Contact SHBC for product specifications, samples, technical information, bulk supply or customized blue carboxyl particle requirements.