LowCross-Buffer® PROTEIN-FREE/ANIMAL-FREE used as an assay buffer helps you to improve signal to noise ratio.
Protein array
ELISA
Frequent asked questions (FAQs):
What is specific to LowCross-Buffer® ANIMAL-FREE?
LowCross-Buffer® ANIMAL-FREE is a newly developed sample buffer for immunoassays (e.g. ELISA, Western blotting, protein arrays and immuno-PCR). It helps to reduce interferences. These are for example, nonspecific binding, cross reactivities and matrix effects. High affinity binding between antibody and antigen is not negatively effected, while unwanted binding of the antibody is inhibited.
Why does LowCross-Buffer® ANIMAL-FREE reduce matrix effects?
Most of the so called matrix effects are based on unwanted low or medium affinity binding of matrix components (e.g. serum proteins from human serum specimen) to analyte or antibody. The analyte can be masked by proteins or other components of the specimen. Thus the antibody can’t bind the analyte. Also antibodies can be masked by matrix components. LowCross-Buffer® ANIMAL-FREE reduces the masking of antibodies.
How do I have to use LowCross-Buffer® ANIMAL-FREE?
LowCross-Buffer® ANIMAL-FREE is a dilution buffer for specimens (e.g. serum or plasma) and/or for detection antibodies. It depends on the interference. If the nonspecific binding or cross reactivity comes from the detection antibody we recommend diluting the detection antibody in LowCross-Buffer® ANIMAL-FREE.
Do I have to dilute LowCross-Buffer® ANIMAL-FREE?
No, as LowCross-Buffer® ANIMAL-FREE is ready-to-use. Sample or detection antibodies are diluted directly with the buffer. Only in competitive assays and some applications of immunohistochemistry it can be useful to dilute LowCross-Buffer® ANIMAL-FREE in water or physiological buffers. In this case the user has to find out the ideal mixing ratio by testing.
Can LowCross-Buffer® ANIMAL-FREE be used with monoclonal and polyclonal antibodies?
Yes, however, if you use polyclonal antibodies they consist of many different antibodies with different affinities. LowCross-Buffer® ANIMAL-FREE only allows high affinity binding whereas low and medium affinity binding will be reduced. If you use LowCross-Buffer® it can be necessary to increase the concentration of the polyclonal detection antibody moderately. The increase of the antibody concentration also increases the concentration of high affinity antibodies, while LowCross-Buffer® ANIMAL-FREE inhibits binding of low and medium affinity antibodies. Whether you have to increase the concentration of antibodies in the assay or not depends on the quality of the antibodies.
Can buffer components influence the colour reaction of enzymatic detection?
LowCross-Buffer® ANIMAL-FREE doesn’t influence the enzymatic activity of alkaline phosphatase or of peroxidase negatively. Sometimes users detect an increase of enzymatic activity by incubating the labelled detection antibody in LowCross-Buffer® ANIMAL-FREE.
I get a high background in my sandwich ELISA which is detected by a peroxidase labelled secondary antibody. What can be the reason and can LowCross-Buffer® ANIMAL-FREE help?
It’s important to know if the secondary antibody was pre-adsorbed against other antibodies of other mammalian species. Secondary antibodies against rabbit IgG can also crossreact with high affinity with mouse IgG or goat IgG unless purified against antibodies of these species. The reason is the high sequence homology of mammalian antibodies. Secondary antibodies are often not purified (pre-adsorbed) and so crossreact with high affinity. In this case LowCross-Buffer® will not improve results: replace instead the secondary antibody with a pre-adsorbed antibody which does not crossreact with the capture antibody.
Can I use LowCross Buffer® ANIMAL-FREE in combination with fluorescent dyes e.g. in protein arrays?
Yes, for protein arrays there are positive results. When using cyan dyes (e.g. Cy5, Cy3, Oyster-dyes) an increase of fluorescence in some applications could be observed.
How often can I freeze and thaw LowCross-Buffer® ANIMAL-FREE?
LowCross-Buffer® ANIMAL-FREE tolerates multiple freeze and thaw cycles. Just make sure you the buffer is mixed thoroughly before use.
Can LowCross-Buffer® ANIMAL-FREE replace a blocking solution for surfaces (e.g. Western blotting membranes, ELISA plates)?
No, not at all. LowCross-Buffer® ANIMAL-FREE is not a blocking buffer for surfaces. It is rather an assay buffer to be used for dilution of the specimens or antibodies. For blocking of surfaces such as membranes, we recommend using The Blocking Solution. This casein-based blocker is much more potent than most known blockers commercially available.
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Product Descriptions & Guides
Product Inserts and Data Sheets
| Brand | CANDOR Bioscience |
| Code | 300 125 |
Product Flyers and Application Guides
Assay Optimizers
Assay Defender® Cat. No. #180
LowCross-Buffer® Cat. No. #100
LowCross-Buffer® Cat. No. #101, #102
LowCross-Buffer® Animal-free/Protein-free Cat. No. #300
Low-Cross-HRP® Cat. No. #200
LowCross® HRP-Stab Cat. No. #270
LowCross® HRP-Stab Animal-free/Protein-free Cat. No. #370
Sample Buffer Cat. No. #105, #106
Sample Buffer Animal-free/Protein-free Cat. No. #305
Covid-19 Inactivation and Dilution Buffer
SafetyTector™ S Cat. No. #400
Blockers
The Blocking Solution Cat. No. #110
BSA-Block Cat. No. #115
PlateBlock™ Cat. No. #112
SmartBlock™ Cat. No. #113
Stabilizers
Antibody Stabilizer TRIS Cat. No. #130
Antibody Stabilizer TRIS Animal-free/Protein-free Cat. No. #330
Antibody Stabilizer PBS Cat. No. #131
Antibody Stabilizer PBS Animal-free/Protein-free Cat. No. #331
AP-Protector® Cat. No. #235
Liquid Plate Sealer® Cat. No. #160
Liquid Plate Sealer® Animal-free Cat. No. #163
HRP-Protector™ Cat. No. #222
HRP-Protector™ Animal-free/Protein-free Cat. No. #322
Standard Buffers (ready-made)
Coating Buffer pH 7.4 Cat. No. #120
Coating Buffer pH 9.6 Cat. No. #121
Stripping Buffer Cat. No. #150
Washing Buffer PBS Cat. No. #140
Washing Buffer PBS IHC Cat. No. #141
Washing Buffer TRIS Cat. No. #145
Washing Buffer TRIS IHC Cat. No. #146
Publications
CoViD-19-antibody-test-challenge
Interference and HAMA problems
IVD technology article
Long-term stabilization of assay components
Optimisation of assays: Interference in immunoassays recognize and avoid
SARS-CoV-2 antigen tests: safety for less than 5 cents per test
Specificity, positive predictive value and validation statistics in the context of CoViD-19
The appropriate blocker — A short overview
The right strategy saves much costs
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