Practical guides to the methods our reagents are used for: ELISA, antibodies, western blot and IHC, qPCR, DNA and RNA extraction, cloning, enzyme activity and cell assays. Each one links to the range that supplies the workflow.
ELISA kits
Every ELISA format detects an antigen with an antibody and an enzyme, but they suit different targets. Here is how each works, which one a quantitative kit is likely to use, and how to read the results.
5 minute read
ELISA kits
Most failed ELISAs fail before the plate is opened. This guide covers collection, centrifugation, storage and dilution for each common sample type, and the checks that prove your matrix is not skewing the result.
4 minute read
ELISA kits
High background usually means washing or detection reagent; no signal usually means a step, a reagent or the sample. Here is how to tell which, using the wells you already ran.
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Antibodies
Antibodies are the most widely used detection reagent in biology. This guide walks through each application, what the antibody actually binds in it, and why an antibody that works in one method can fail in another.
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Antibodies
Polyclonals see many epitopes, monoclonals see one. That single difference decides how they behave in western blot, IHC, ELISA and IP, how consistent they are from lot to lot, and much of what they cost.
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Antibodies
The lysis buffer decides which proteins you extract and whether their complexes survive. Here are the standard recipes, what each component does, and which buffer to choose for western blot, IP and co-IP.
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Antibodies
Formalin fixation hides epitopes; heat and the right buffer bring them back. This is the Tris-EDTA pH 9 recipe, a heating protocol for pressure cooker, microwave and water bath, and how to decide between it and citrate pH 6.
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Antibodies
Start by finding out whether the protein reached the membrane. A Ponceau S stain and a prestained ladder split most failed blots into two halves in a few minutes.
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qPCR / RT-PCR
End-point PCR tells you whether a sequence is there, qPCR tells you how much, and RT-qPCR does the same for RNA. Here is what changes between them and the reagent list for each.
4 minute read
qPCR / RT-PCR
A 2X qPCR master mix looks like a commodity until it does not match your instrument or chemistry. This guide covers dye vs probe, ROX levels, hot-start, setup volumes and how to validate efficiency.
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qPCR / RT-PCR
Your controls usually say what went wrong. A positive control, a no-template control, a no-RT control and one dilution of the sample separate template, inhibition and primer problems.
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DNA and RNA extraction
Every extraction does the same four things: lyse, separate, wash, elute. The chemistry you use for each step decides yield, purity and how many samples you can run a day.
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DNA and RNA extraction
Blood brings heme, plants bring polysaccharides, stool brings humic acids and tough bacteria, viral samples bring almost no RNA. Here is what each sample needs from an extraction kit.
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DNA and RNA extraction
A poor A260/230 usually means salt or phenol carry-over rather than bad RNA. Low yield usually starts at lysis. Here is how to read the numbers and what to change.
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Molecular biology
A DNA ladder is only useful if its bands bracket your fragment on the gel you are running. This guide matches ladder ranges to agarose percentages and covers loading, staining and quantification.
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Molecular biology
Cloning is a chain of small steps, and most failures trace back to one of them. Here is the whole chain, the reagent each step needs, and how to check you have the right clone before you build on it.
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Molecular biology
Read the gel first. No band, a smear, extra bands and a fuzzy band under 100 bp each point to a different change, and the positive control tells you whether to trust the mix.
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Biochemical and cell assays
Succinate dehydrogenase is the only enzyme in both the Krebs cycle and the electron transport chain, which makes its activity a direct read on mitochondrial function. Here is how the assay works and how to get numbers you can trust.
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Biochemical and cell assays
Most enzyme activity kits turn a reaction you cannot see into a colour change you can measure. Once you know the two or three ways they do it, choosing a kit and reading the result gets much easier.
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Biochemical and cell assays
Viability assays measure metabolism, membranes or ATP, never cell number directly. Knowing which one you are measuring explains most odd results and tells you which assay to pick.
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Biochemical and cell assays
Many strange MTT results come from the compound reducing the dye, or from formazan crystals lost during aspiration. One cell-free blank and a seeding curve catch most of them.
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Tell us what you are trying to measure and the samples you have. We’ll point you to the reagents and send the datasheets.