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Why do you use a cell-based assay instead of HPLC to determine the tetracycline concentration/presence in Fetal Bovine Serum, Tet system approved? Product FAQ

Answer

While competitors may use HPLC or other assays to determine the presence of tetracycline, we developed a cell-based assay because we wanted to verify that the tetracycline present, if any, in this product would not be enough to alter the experiment. The only way to confirm this is to actually demonstrate the efficacy of the serum in a dish with cells (cell-based assay).

Find additional tips, troubleshooting help, and resources within our Cell Culture Support Center.

Answer Id: E19365

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What are some applications of Nunc 384-Well Black or White Microplates that have a cell culture-treated surface? Product FAQ

Answer

We recommend using the Nunc 384-Well Black Microplates for cell-based assays using fluorescent detection. Viability stains such as fluorogenic esterases can be used for proliferation, toxicity, and drug resistance or sensitivity assays. Many types of fluorochrome-conjugated antibodies are available for performing cell-based immunoassays. Fluorescent reporter genes are widely used for determining cell transfection.
We recommend using the Nunc 384-Well White Microplates for cell-based assays using luminescent detection. Viability stains such as luciferin/luciferase can be used for proliferation, toxicity, and drug resistance or sensitivity assays. Cell-based immunoassays can be performed using a HRP-conjugated antibody with a luminol-based substrate. Luciferase reporter genes are widely used for determining cell transfection.

Answer Id: E17697

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How do I decide whether I should use a biochemical assay or a cell-based assay for drug discovery studies? Product FAQ

Answer

Initial investigations are typically done with biochemical assays with cell-based assays as follow-up.

Find additional tips, troubleshooting help, and resources within our Drug Discovery & Development Support Center.

Answer Id: E16519

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In my enzyme activity assay, how does the shape of the microplate well affect results if my sample volume is the same? Product FAQ

Answer

Conical and curved-bottom microplate wells concentrate the light signal into a smaller area relative to a flat-bottomed microplate well. The smaller surface at the air-liquid interface also slows the rate of evaporation. Flat-bottomed plates are recommended for cell culture and can be used in non-cell based assays but may not be suitable for non-cell based assays if smaller volumes are used. At lower volumes, a significant amount of sample volume is found at the well walls, the liquid-surface interface, creating a meniscus (less volume in the center, more volume at the edges). 

Find additional tips, troubleshooting help, and resources within our Protein Assays and Analysis Support Center.

Answer Id: E15867

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With TRANSiPORT solute carrier (SLC) transporter cells, what should my choice of measurement be for SLC transporter activity? Product FAQ

Answer

Cell-based assays can be performed using radioisotope-labeled compounds, fluorescence-labeled compounds, or non-labeled compounds. The amount of substrate transported into the cells can be measured directly using a liquid scintillation counter, fluorescence plate reader, or LC-MS/MS, thereby allowing direct evaluation of SLC transporter activity.

Answer Id: E15895

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Why is the EC50 (or IC50) quite different between my biochemical and cell-based assays? Product FAQ

Answer

-The compound may not be able to get across the cell membrane or is being pumped out.

-The compound in the cell-based assay may be targeting an inactive form of the kinase or an upstream or downstream kinase. Kinase activity assays must use the active form of the kinase and as such, the inactive form of the kinase cannot be studied. Please note however that a binding assay, such as the LanthaScreen Eu Kinase Binding Assay, can be used to study the inactive form of a kinase.

Find additional tips, troubleshooting help, and resources within our Drug Discovery & Development Support Center.

Answer Id: E16548

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How is Fetal Bovine Serum, Tet system approved verified to be tetracycline-free? Product FAQ

Answer

Fetal Bovine Serum, Tet system approved is not tetracycline-free, and no serum can be absolutely confirmed to be tetracycline-free without altering the performance of the product. We developed a cell-based assay to confirm that tetracycline, if present, is not in high enough concentrations to alter Tet experiments.

Find additional tips, troubleshooting help, and resources within our Cell Culture Support Center.

Answer Id: E19364

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LanthaScreen ERK2 U2OS Cell-based Assay Manual / Product Insert

  • Version: 15 July 2008
Catalog # K1587

LanthaScreen PDCD4 HEK293E Cell-based Assay Manual / Product Insert

  • Version: 14 April 2008
Catalog # K1593

LanthaScreen STAT1 U2OS Cell-based Assay Manual / Product Insert

  • Version: 12 October 2007
Catalog # K1469

LanthaScreen STAT3 GripTite Cell-based Assay Manual / Product Insert

  • Version: 18 June 2008
Catalog # K1488

How do I convert the ED50 value (obtained via functional ELISA) to the equivalent ED50 value for a cell-based assay? Product FAQ

Answer

Although in both cases, a lower ED50 indicates higher biological activity, these two values can't be directly converted. Because the ED50 from a functional ELISA indicates the concentration of a given growth factor or cytokine that gives half maximum binding to its receptors, this is not necessarily the concentration that gives half maximal biological response in the target cell. In addition, the ED50 of the cell-based assay varies significantly depending on the indicator cells used. ED50 values in a functional ELISA do not change that much

Find additional tips, troubleshooting help, and resources within our Antibodies and Immunoassays Support Center.

Answer Id: E12198

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LanthaScreen PRAS40 HEK293E Cell-based Assay Protocol Manual / Product Insert

  • Version: 30 October 2010
Catalog # K1528

LanthaScreen AKT HEK293E Cell-based Assay Protocol Manual / Product Insert

  • Version: 14 May 2008
Catalog # K1615

GeneBLAzer M5 CHO-K1 Cell-based Assay Manual / Product Insert

  • Version: 7 November 2010
Catalog #
  • K1728
  • K1351(Discontinued)
  • K1228
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