Shop All General Immunoassay Buffers & Reagents

Guardian™ Peroxidase Conjugate Stabilizer/Diluent (Thermo Scientific™)

Thermo Scientific Guardian Peroxidase Conjugate Stabilizer/Diluent preserves the functional integrity and activity of horseradish peroxidase conjugated antibodies and other proteins at very dilute concentrations for long-term storage.

Features of Guardian Peroxidase Conjugate Stabilizer/Diluent:

Preserves HRP activity—no significant loss of HRP activity over a six-month period at room temperature (1:1000 dilution) or 12 months at 4°C
Convenient—store ready-to-use dilutions (1:1000 to 1:100,000) that maintain enzyme activity in the refrigerator—no aliquoting or freezing
Assay compatible—simply add your favorite blocking buffer to create the ideal diluent for your HRP-based ELISA system or store the HRP conjugate as a 1:1000 stock solution for Western blots and dilute in the final assay buffer
Saves money—less expensive than competitor formulations or ordering new HRP conjugates

With Guardian Peroxidase Conjugate Stabilizer/Diluent, typical 1 mg/mL antibody or streptavidin peroxidase conjugates can be diluted as much as 100,000-fold for storage at 4°C. Most ELISA and blotting applications for HRP conjugates require dilution of typical 1 mg/mL stocks by at least 1000-fold (to 1 µg/mL). Sensitive assay systems, such as with chemiluminescent substrates, often require dilution up to 100,000-fold (10 ng/mL). The Guardian Solution enables these 1X working concentrations of HRP conjugate to be prepared in advanced and stored at 4°C for 12 months or at room temperature for six months.For blotting applications, it is usually best to prepare a concentration for storage that can be diluted 10-fold in assay buffer (which may contain blocking components) for final use.

Typical colorimetric ELISA procedures requires that 10 mL of HRP-conjugated secondary antibody be diluted 1000- to 5000-fold from a 1 mg/mL stock solution. That necessitates pipetting 2 to 10 µL of stock into a tube with 10 mL of diluent. More sensitive assay systems, such as Western blots with Thermo Scientific SuperSignal West Pico, Dura or Femto Chemiluminescent Substrates for HRP, require a second round of dilution to achieve the needed working concentration of HRP conjugate. With Guardian Stabilizer-Diluent, HRP conjugates can be pre-diluted and stored at concentrations that are either ready to use or easily diluted 10- to 100-fold for final use. Preparing larger volumes of pre-diluted stocks ensures consistency and greater accuracy for assays performed repeatedly day after day.

StartingBlock™ (PBS) Blocking Buffer (Thermo Scientific™)

StartingBlock Blocking Buffer is a single purified protein for fast blocking of western blots and ELISA assays. It provides broad compatibility with a wide range of antibodies, antibody combinations, and other protein probing and assay systems. StartingBlock buffer is available in PBS and TBS with and without Tween20.

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Features of StartingBlock Blocking Buffers:
Strip and reprobe without reblocking—blots stay blocked even after stripping with Thermo Scientific Restore Stripping Buffer (Cat. No. 21059)
Compatible with many detection systems—western blot, ELISA, and IHC with antibody or avidin/biotin probes (blocker is serum and biotin-free)
Short blocking times—less than 15 minutes for nitrocellulose or PVDF membranes, almost instantaneous for polystyrene microplate wells
Biotin- and serum protein-free formulation

Related products
StartingBlock T20 (PBS) Blocking Buffer
StartingBlock (TBS) Blocking Buffer
StartingBlock T20 (TBS) Blocking Buffer

Pierce™ Clear Milk Blocking Buffer (10X) (Thermo Scientific™)

Pierce Clear Milk Blocking Buffer (10X) is a long-shelf life, high-performance replacement for homemade non-fat milk blocking buffers in western blotting applications.

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Our Clear Milk Blocking Buffer (10X) is a pre-formulated milk solution, clarified and stabilized for blocking excess nonspecific binding sites, reducing background in western blotting applications and diluting antibodies when used with nitrocellulose and PVDF membranes. It provides lower background, enhanced sensitivity, extended shelf life, and reproducible results compared to homemade buffers based on dissolved non-fat dry milk. Not recommended for avidin-based techniques because it contains some endogenous biotin.

SuperBlock™ T20 (PBS) Blocking Buffer (Thermo Scientific™)

SuperBlock Blocking Buffer is optimized solution containing a single purified glycoprotein that provides incredibly fast and effective blocking for ELISA, IHC, and western blot analysis.

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Features of SuperBlock Blocking Buffer:
Blocking time—block membranes in 5 to 10 minutes and ELISA plates in 2 minutes
Applications—ELISA, western blotting, IHC; biotin-free for use with streptavidin system
Stability—store buffer at 4°C for one year; store blocked plates dry for up to 12 months

Blocking micro-plates, membranes or tissues with a SuperBlock Buffer yields a high signal-to-noise ratio in most detection systems. The protein-based formulation does not contain any immunoglobulins, albumin, or endogenous biotin, making it compatible in many situations where traditional blocking agents fail. The buffer is especially effective at blocking coated polystyrene microplates (96-well plates) and stabilizing them for drying and storage for later use.

Related products
SuperBlock (PBS) Blocking Buffer
SuperBlock (TBS) Blocking Buffer
SuperBlock T20 (TBS) Blocking Buffer
SuperBlock (TBS) Blocking Buffer Dry Blend

StartingBlock™ (TBS) Blocking Buffer (Thermo Scientific™)

StartingBlock Blocking Buffer is a single purified protein for fast blocking of western blots and ELISA assays. It provides broad compatibility with a wide range of antibodies, antibody combinations, and other protein probing and assay systems. StartingBlock buffer is available in PBS and TBS with and without Tween20.

Compare and view all available blocking buffers

Features of StartingBlock Blocking Buffers:
Strip and reprobe without reblocking—blots stay blocked even after stripping with Thermo Scientific Restore Stripping Buffer (Cat. No. 21059)
Compatible with many detection systems—western blot, ELISA, and IHC with antibody or avidin/biotin probes (blocker is serum and biotin-free)
Short blocking times—less than 15 minutes for nitrocellulose or PVDF membranes, almost instantaneous for polystyrene microplate wells
Biotin- and serum protein-free formulation

Related products
StartingBlock (PBS) Blocking Buffer
StartingBlock T20 (PBS) Blocking Buffer
StartingBlock T20 (TBS) Blocking Buffer

I-Block™ Protein-Based Blocking Reagent (Invitrogen™)

I-Block reagent is a highly purified casein-based blocking reagent. It provides superior blocking compared to both dried milk and BSA. Unlike other casein-based blocking reagents, I-Block reagent is essentially biotin-free. I-Block reagent is tested in assays using Tropix substrates and alkaline phosphatase conjugates, and is useful as a blocking reagent in membrane-based and immunoassay applications.

The suggested working concentration is 0.2% (w/v) for detection of nucleic acids on neutral or positively-charged nylon membranes and for immunoassays and protein detection on membranes (nitrocellulose, PVDF, or neutral nylon). For protein detection on positively-charged nylon membrane (such as TropilonPlus membrane), a concentration of 3% is recommended. I-Block blocking solution is prepared in either Tris- or phosphate-buffered saline buffer with heating (40-50°C).

This casein-based blocking reagent can be used with Western-Light, Western-Light Plus, Western-Star, ELISA-Light, Southern-Light, and Southern-Star detection systems.

cAMP-Screen™ Wash Buffer (Invitrogen™)

This Wash Buffer is suitable for use with the cAMP-Screen® or cAMP-Screen Direct® Immunoassay system.

For Research Use Only. Not for use in diagnostics procedures.

Miser™ Antibody Extender Solution NC (Thermo Scientific™)

Thermo Scientific Pierce Antibody Extender Solution NC is a post-transfer nitrocellulose membrane-treatment reagent that enables Western blot detection with much less primary antibody.

Features of Antibody Extender Solution NC:

Achieve equivalent signal—use at least three times less primary antibody than normal and retain comparable or better signal detectability
Any detection mode or enzyme—the method works with both colorimetric and chemiluminescent detection modes and with horseradish peroxidase (HRP) and alkaline phosphatase (AP) systems
Easy-to-perform, 10-minute protocol—invest a few minutes and save money on your primary antibody; our scientists have reduced their use of expensive primary antibodies by up to 100-fold with this product

By treating nitrocellulose membranes for a few minutes in this reagent immediately after transfer and before probing, you can use much less (more dilute) primary antibody solutions while obtaining the same level of detection. This conserves use of expensive and rare antibodies, enabling more experiments to be performed with the same amount of antibody. The reagent is so effective that our scientists have observed antibody cost reductions of 10-, 25- and even 100-times (depending on the antigen and primary antibody directed against that antigen).

SuperBlock™ (PBS) Blocking Buffer - Blotting (Thermo Scientific™)

Thermo Scientific SuperBlock (PBS) Blocking Buffer - Blotting is optimized PBS solution containing a protein that provides incredibly fast and effective blocking for Western blot analysis.

Features of SuperBlock (PBS) Blocking Buffer - Blotting:

Fast—block membranes in 5 to 10 minutes
Flexible—guaranteed to be biotin-free for use with streptavidin system
Low background—the non-serum protein solution yields a high signal-to-noise ratio
Stable—store buffer at 4°C for one year; store blocked plates dry for up to 12 months

Blocking micro-plates, membranes or tissues with a SuperBlock Buffer yields a high signal-to-noise ratio in most detection systems. The protein-based formulation does not contain any immunoglobulins, albumin or endogenous biotin, making it compatible in many situations where traditional blocking agents fail. The buffer is especially effective at blocking coated polystyrene microplates (96-well plates) and stabilizing them for drying and storage for later use.

Related Products
SuperBlock™ (PBS) Blocking Buffer
SuperBlock™ T20 (PBS) Blocking Buffer
SuperBlock™ (TBS) Blocking Buffer
SuperBlock™ T20 (TBS) Blocking Buffer
SuperBlock™ (TBS) Blocking Buffer Dry Blend

Normal Horse Serum (Invitrogen™)

Normal Horse Serum Control for IF, ICC, IHC, BLOCK, Ctrl

Pierce™ Protein-Free (PBS) Blocking Buffer (Thermo Scientific™)

Pierce Protein-Free Blocking Buffer is a non-protein compound that provides effective blocking for membrane-based and plate-based protein detection methods, resulting in extremely low background. It is supplied in a ready-to-use format.

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Features of Protein-Free Blocking Buffer:
Protein-free blocker—minimizes or eliminates cross-reactivity associated with protein-based blocking buffers
Applications—western blotting (membranes), ELISA (microplates), and arrays (coated glass slides)
Streptavidin-friendly—free of biotin; no interference with avidin-biotin detection systems
High-performance—optimized and validated in many protein methods to provide high signal-to-noise ratio (i.e., no quenching of specific binding and signal but eliminating nonspecific binding and background)

Traditional blocking buffers contain proteins that can cross-react in certain immunodetection systems, resulting in high background and reduced signal. Pierce Protein-Free Blocking Buffers are devoid of protein while remaining highly effective at blocking plates, membranes, and other surfaces for ELISA, western blotting, glass slide arrays, and other applications.

Related products
Pierce Protein-Free T20 (PBS) Blocking Buffer
Pierce Protein-Free (TBS) Blocking Buffer
Pierce Protein-Free T20 (TBS) Blocking Buffer

Pierce™ Fast Blocking Buffer (Thermo Scientific™)

Pierce Fast Blocking Buffer effectively and reliably blocks western blots in just five minutes to provide low-background results for traditional western blotting protocols.

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Pierce Fast Blocking Buffer streamlines western blot protocols by providing consistent, high-quality blocking for nitrocellulose or PVDF membranes in only five minutes, producing results comparable to traditional blockers. Blocking and probing steps with Fast Blocking Buffer prevent nonspecific binding of detection antibodies during probing steps but allows specific detection to occur. Pierce Fast Wash Buffer provides efficient membrane washing after incubation with a primary and secondary antibody to effectively shorten total washing time to 20 minutes (from the typical 90 minutes). This buffer is compatible with antibodies and biotin-avidin systems, as well as both nitrocellulose and PVDF membranes.

Related products
Pierce Fast Wash Buffer, 10X

Pierce™ Protein-Free T20 (TBS) Blocking Buffer (Thermo Scientific™)

Pierce Protein-Free Blocking Buffer is a non-protein compound that provides effective blocking for membrane-based and plate-based protein detection methods, resulting in extremely low background. It is supplied in a ready-to-use format.

Compare and view all available blocking buffers

Features of Protein-Free Blocking Buffer:
Protein-free blocker—minimizes or eliminates cross-reactivity associated with protein-based blocking buffers
Applications—western blotting (membranes), ELISA (microplates), and arrays (coated glass slides)
Streptavidin-friendly—free of biotin; no interference with avidin-biotin detection systems
High-performance—optimized and validated in many protein methods to provide high signal-to-noise ratio (i.e., no quenching of specific binding and signal but eliminating nonspecific binding and background)

Traditional blocking buffers contain proteins that can cross-react in certain immunodetection systems, resulting in high background and reduced signal. Pierce Protein-Free Blocking Buffers are devoid of protein while remaining highly effective at blocking plates, membranes, and other surfaces for ELISA, western blotting, glass slide arrays, and other applications.

Related products
Pierce Protein-Free (PBS) Blocking Buffer
Pierce Protein-Free T20 (PBS) Blocking Buffer
Pierce Protein-Free (TBS) Blocking Buffer

Blocker™ FL Fluorescent Blocking Buffer (10X)

Blocker FL Fluorescent Blocking Buffer is designed to block excess nonspecific binding sites to help reduce background fluorescence in western blotting applications. Blocker FL buffer helps enhance fluorescent protein detection by increasing the signal-to-noise ratio in blotting applications where background fluorescence may otherwise interfere with signal detection.

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Working reagent is prepared by adding 1 part Blocker FL buffer to 9 parts ultrapure water. Optimal concentration should be determined empirically for each system. Compatible with both nitrocellulose and PVDF membranes.

Pierce™ Stable Peroxide Substrate Buffer (10X) (Thermo Scientific™)

Thermo Scientific Pierce Stable Peroxide Substrate Buffer (10X) include optimized, reliable and convenient stock solutions of peroxide for HRP-based assays detection.

Features of Stable Peroxide Substrate Buffer (10X):

• Ready-to-use
• Minimize assay-to-assay variability

Buffered stable hydrogen peroxide (H2O2) is used by researchers who prefer to make their own HRP-ELISA substrates. This is easily done by adding a chromogen of choice to the buffer. Stable Peroxide Substrate Buffer has a long shelf life (12 months after receipt) and is provided as a 10-fold concentrate. A total volume of 1000 mL can be made from one 100 mL bottle of concentrate. If you use 10 mL of substrate per plate, this will allow you to make substrate for 100 plates from only one bottle of Stable Peroxide Substrate Buffer.

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Pierce™ Diethanolamine Substrate Buffer (5X)