Streptavidin Conjugation

Streptavidin conjugation plays a pivotal role in various biochemical and diagnostic applications due to the highly specific and stable biotin-binding capability of streptavidin. As a key tool in fields like flow cytometry, enzyme-linked immunosorbent assay (ELISA), immunohistochemistry, and microarray assays, this conjugation technique enables precise detection and quantification of biological molecules. BOC Sciences offers a wide range of streptavidin conjugation services, tailored to meet the diverse needs of scientific research and industrial applications.

What is streptavidin?

Streptavidin is a biotin-binding protein derived from Streptomyces avidinii, known for its extraordinarily high affinity for biotin (vitamin B7). This non-glycosylated tetrameric protein binds biotin with an affinity close to the femtomolar range, making it a robust tool in applications that require highly specific molecular interactions. Its structural similarity to avidin, but with reduced nonspecific binding due to the absence of glycosylation, makes streptavidin a preferred reagent in many assays.

Streptavidin is composed of four identical subunits, each of which binds a single biotin molecule. This tight binding is resistant to environmental changes such as pH and temperature, which ensures the stability of streptavidin conjugates in various experimental conditions. Unlike avidin, streptavidin has a near-neutral isoelectric point (pI), which further reduces nonspecific interactions, enhancing its specificity for targeted molecular recognition in biochemical assays.

Advantages of streptavidin conjugation

Streptavidin conjugation refers to the process of chemically attaching streptavidin to various biomolecules, fluorophores, enzymes, nanoparticles, and magnetic beads. This allows streptavidin to bind biotinylated targets, providing a powerful platform for signal amplification, molecular labeling, and complex detection schemes. The near-neutral pI of recombinant streptavidin (~6.8-7.5) further reduces nonspecific binding, increasing assay accuracy.

Enhanced sensitivity: By coupling streptavidin with signal-generating molecules like fluorophores or enzymes, detection assays such as ELISA, western blotting, and immunohistochemistry are significantly more sensitive, allowing for the identification of minute quantities of target analytes.

Flexibility: Streptavidin can be conjugated to a wide range of molecules and surfaces, including fluorescent dyes, enzymes, nanoparticles, and magnetic beads, enabling versatile applications across molecular biology, immunology, and diagnostics.

Cost-effectiveness: Biotin-streptavidin systems are relatively easy to prepare and have long-term stability, making them a cost-effective solution for various laboratory protocols.

Reduced non-specific binding: Recombinant streptavidin has low nonspecific binding properties, particularly in assays where background noise must be minimized, such as in tissue staining for immunohistochemical (IHC).

Applications of streptavidin conjugation

Streptavidin conjugation has broad applications across multiple scientific disciplines. Below are some key areas where streptavidin conjugates are widely used:

Flow cytometry: Streptavidin conjugates are used to label biotinylated antibodies for detecting specific cell populations.

Cell imaging: Fluorescently labeled streptavidin conjugates can be used for cell imaging by labeling biotinized molecules within cells and observing their distribution and dynamics within cells.

ELISA: Enzyme-linked streptavidin conjugates (such as horseradish peroxidase or alkaline phosphatase) are used to amplify signals in immunoassays, enhancing sensitivity.

Western Blotting: Streptavidin conjugates detect biotinylated proteins, allowing for specific visualization of target proteins on nitrocellulose or PVDF membranes.

Immunohistochemistry and immunocytochemistry: Streptavidin conjugates, combined with biotinylated primary or secondary antibodies, help visualize the localization of proteins within cells or tissues.

Affinity purification: Streptavidin conjugated to magnetic beads or resin facilitates the separation and purification of biotinylated proteins or nucleic acids from complex mixtures.

Drug delivery: Nanoparticles conjugated to streptavidin can be directed to biotinylated targets, offering a platform for precision-targeted therapeutic delivery.

Our streptavidin conjugation services

BOC Sciences provides a wide range of specialized streptavidin conjugation services designed to meet diverse needs across scientific and industrial applications. With a focus on precision and efficiency, these services are optimized to maximize the binding capacity of streptavidin with biotinylated molecules, ensuring high-quality results with strong performance consistency.

Streptavidin-enzyme conjugation

BOC Sciences offers streptavidin conjugation to enzymes such as horseradish peroxidase (HRP) and alkaline phosphatase (AP), with binding efficiencies exceeding 95%. Each conjugate batch undergoes rigorous quality testing to ensure enzyme activity remains above 90% after conjugation. These enzyme-labeled streptavidin conjugates deliver strong, stable binding, ideal for applications that require robust signal amplification.

Streptavidin-quantum dot conjugation

Leveraging the unique optical properties of quantum dots, BOC Sciences provides qdot-streptavidin conjugates. These are ideal for multiplex assays such as Luminex and fluorescence-based microarrays. Each streptavidin-quantum dot conjugate offers enhanced brightness and over 10-fold greater photostability compared to traditional fluorophores. This results in long-lasting signals during prolonged imaging experiments. Our quantum dot conjugation yields consistent batch-to-batch fluorescence intensities within 5%, providing reliable tools for multiplexed fluorescence assays.

Alexa Fluor fluorescent streptavidin conjugation

Our Alexa Fluor-streptavidin conjugation services produce highly photostable and bright conjugates available in a wide range of dye wavelengths (e.g., Alexa Fluor 488, 568, and 647). These conjugates are optimized to maintain over 95% of their fluorescence intensity after 24 hours of continuous illumination, ensuring minimal photobleaching during imaging experiments. In flow cytometry applications, Alexa Fluor-streptavidin conjugates achieve a signal-to-noise ratio exceeding 100:1, allowing for precise multi-color staining and detection.

Streptavidin-particle conjugation

BOC Sciences offers streptavidin conjugation to a variety of particles, including microspheres (100 nm to 5 µm) and nanospheres (20 to 200 nm). These conjugates achieve a biotin-binding capacity of up to 10 mg/mL, making them essential for high-efficiency capture and separation of biotinylated targets. In typical bioseparation applications, such as affinity chromatography, our streptavidin-microsphere conjugates achieve purification yields exceeding 90%, with minimal non-specific binding.

Streptavidin-resin conjugation

Our streptavidin-resin conjugation services utilize high-performance resins with binding capacities of over 30 mg/mL for biotinylated proteins. These resins are carefully selected to minimize non-specific binding while ensuring high recovery rates (above 85%) for affinity purification processes. BOC Sciences' streptavidin-resin conjugates are used extensively in large-scale purification, enabling consistent yields in high-throughput biomanufacturing environments.

Streptavidin-nanoparticle conjugation

BOC Sciences provides cutting-edge streptavidin-nanoparticle conjugation services using nanoparticles with diameters ranging from 10 to 100 nm, including streptavidin-silver nanoparticle conjugation and streptavidin-gold nanoparticle conjugation. Our conjugation protocols ensure a binding capacity of up to 200 µg of biotinylated molecules per mg of nanoparticles, making these conjugates highly efficient for targeted molecular delivery and detection. Each batch of streptavidin-nanoparticle conjugates undergoes stringent testing to ensure particle uniformity (less than 5% variance in size) and stable binding affinity.

Schematic representation of GNCIA in detection of HIV-1 p24 antigen. (Kurdekar, A. D., 2018)

Streptavidin-silicone nanoparticle conjugation

Silicone nanoparticles are synthesized, often using methods like sol-gel processes or emulsion polymerization. The surface of silicone nanoparticles is often modified to include functional groups such as amine (-NH2), carboxyl (-COOH), or hydroxyl (-OH) groups. This is usually done through the addition of silane coupling agents or other chemical modifications that provide reactive sites for further conjugation. Streptavidin can be covalently attached to the nanoparticles using various chemical linkers. Common linkers include carbodiimide chemistry (EDC/NHS activation) to form stable amide bonds between the carboxyl groups on the nanoparticle and the amine groups on the protein.

Streptavidin-magnetic bead conjugation

Our streptavidin-magnetic bead conjugates offer rapid and efficient separation capabilities, with bead sizes ranging from 0.5 to 5 µm. These magnetic beads enable the precise isolation of biotinylated molecules with over 95% purity in less than 15 minutes, streamlining bioseparation workflows. BOC Sciences ensures that each streptavidin-magnetic bead conjugate is compatible with automated systems, achieving high reproducibility in high-throughput environments with process yields above 90%.

Why choose BOC Sciences?

• Excellent one-stop service
• Experienced team of scientists, proficient in biomolecular coupling technology, to ensure the perfect coupling of streptavidin and biomolecules.
• State-of-the-art equipment and process technology to ensure high efficiency and stability of coupling products.
• The service is flexible and can handle a variety of biomolecular types, including proteins, antibodies, nucleic acids, etc., to meet diverse research needs.
• Fast delivery time to help customers accelerate the research process and enhance market competitiveness.
• Strictly follow international quality standards

FAQ

1. What are the main advantages of using streptavidin over avidin?

Streptavidin is less prone to nonspecific binding because it is not glycosylated, making it more suitable for sensitive applications such as IHC and ICC. Additionally, streptavidin has a near-neutral isoelectric point, which further reduces background noise in assays.

2. Can streptavidin conjugates be used with any biotinylated molecule?

Yes, streptavidin conjugates can bind to any biotinylated molecule, including proteins, peptides, antibodies, and nucleic acids.

3. How stable are streptavidin conjugates during long-term storage?

Streptavidin conjugates are highly stable, especially when stored at appropriate conditions (typically 4°C or lower). This long-term stability makes them ideal for assays requiring repeated use over extended periods.

4. What is the minimum sample requirement for conjugation services at BOC Sciences?

The minimum sample requirement varies depending on the service. For example, qdot-streptavidin conjugates require a minimum of 200 µg of biotinylated sample, while streptavidin-HRP conjugation requires 100 µg.