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FAQS

 

 

Flow Cytometry Reagents - Faqs

Questions pertaining to BioGems' line of Conjugated Flow Cytometry Antibodies, SAFIRE Functional Antibodies, Purified Monoclonal Antibodies, Flow Cytometry Buffers and Solutions, and Isotype Controls.
  • What do the application abbreviations stand for?
    • FC – Flow Cytometry FA - Functional Assay IHC – Immunohistochemistry IF - Immunofluorescence IP- Immunoprecipitation N – Neutralization WB- Western Blot
  • What does Biogems offer?
    • Biogems offers a wide comprehensive line of flow cytometry and recombinant protein reagents. We offer a wide range of monoclonal and polyclonal antibodies for the detection of cell surface markers and intracellular cytokines. We sell industry top selling products that are tested to be premium quality at economical prices.
  • How are quality controls established for different lots?
    • Biogems offers products that have consistent quality, purity, and performance across multiple lots. New lots are tested side-by-side with previous lots for consistency.
  • Why are some products listed by number of tests versus µg size?
    • The products listed by test size are titrated for optimal staining of a cell sample in a final volume of approximately 100 µL. The number of cells in a sample has a typical range of 1x10^5 to 1x10^8 cells. The products listed by µg size are based on a defined concentration as opposed to an optimal staining.
  • What epitope does the antibody bind to?
    • Biogems does not at this time perform epitope mapping. In some cases, relying on published research, this information may be listed on the datasheets for certain products
  • What if I want to use less cells or less volume in my sample that is recommended per test?
    • As long as the antibody concentration remains the same, you can use less cells or sample volume per test. If you decrease the sample volume to half the recommended, from 100 µL to 50 µL, you can halve the amount of antibody used. If you keep the recommended sample volume, but decrease the concentration of cells, then we recommend you still follow the recommended amount of antibody.
  • Can antibodies be frozen?
    • Freezing can denature the product and uncouple fluorochromes. The antibodies should be protected from light and stored at the recommended temperature listed for each product.
  • What controls should be used with the flow cytometry experiment?
    • We recommend isotype controls for each flow cytometry experiment and the recommended isotype control can be found on the product page. They retain the non-specific characteristics of the antibody used without the specific target cell binding. Therefore, Isotype controls are important to determine the background staining of an antibody. One can also measure the autofluorescence of a particular cell type with unstained cells.
  • How much or at what concentration should I use the isotype controls?
    • The amount or concentration of isotype controls should match used of the primary antibody. Since concentrations between isotype and primary antibodies vary, the same volume of the solutions may not contain equal amounts of antibody.
  • What is the purity of the antibodies?
    • The monoclonal antibodies are >90% pure as determined by SDS-PAGE.
  • What is the purpose of Tandem Dyes?
    • Tandem dyes are composed of two covalently attached fluorescent molecules. Through the fluorescence resonance energy transfer (FRET) principle, the tandem dye utilizes the excitation spectrum of the donor fluorochrome and the emission property of the acceptor molecule. This property allows for larger stokes shifts, the difference between the excitation and emission range.
  • What is Compensation and why is it important?
    • Fluochromes do not emit at distinct wavelengths but across emission spectrums. Compensation is the process of removing the overlapping spectral regions to eliminate false signals in multicolor staining panels.
  • For products with multiple clones, how should one choose between them?
    • We recommend basing your decision on a search on Google Scholar or Pubmed. These resources can help you research the popularity of these clones compared to each other for your relevant purposes.

Recombinant Proteins - Faqs

Questions pertaining to BioGems' line of Growth Factors, Cytokines, Chemokines, Neurotrophins, and Other Recombinant Proteins.
  • Before releasing our cytokines and cytokine products for sale they are thoroughly analyzed to ensure the following qualities:
    • Authenticity: by N-terminal sequence analysis and, when possible, by SDS-PAGE, RP-HPLC, and Mass Spectrometry analyses versus standards. Purity: by SDS-PAGE and RP-HPLC analysis Biological Activity: by the relevant in vitro or in vivo bioassay. Protein content: by UV spectroscopy, SDS-PAGE analysis and, when possible, by HPLC analysis versus the calibrated standard solution. Endotoxin contamination: by kinetic LAL method. Microbiological contamination: by membrane filtration method; protein solutions are sterile-filtered prior to vialing. The relevant information relating to each product appears on the Certificate of Analysis that is shipped with the product. Please read this information carefully to obtain useful instructions for reconstitution and storage. If, after reading the CoA, you need additional information, please review the following set of questions and answers, or call our technical service department at 800-493-5868.
  • What endotoxin level should be expected when purchasing BioGem's proteins?
    • For most of BioGem's proteins the endotoxin level is guaranteed to be less than 0.1 ng/μg of protein, or 1 EU/μg. However, for many proteins, the actual measured endotoxin values are consistently below this stated endotoxin level. Please contact Technical Support for more information.
  • What should I know about the stability of your protein products?
    • Unless otherwise mentioned on the product information sheet, all of our products are formulated in such a manner that the lyophilized proteins are very stable at room temperature. However, we recommend storing lyophilized products at -20°C. For reconstituted solutions of most products, we recommend short-term storage at 4°C. For longer term storage the protein solution should be stored with a carrier protein (eg. 0.1%BSA) in working aliquotes and stored frozen at -20°C. Please keep in mind that every freeze/thaw cycle may cause some denaturation of the protein.
  • Why can't I see the protein pellet in the vial?
    • Unlike many protein products available on the market, BioGems products are not formulated with carrier protein or other additives (e.g., BSA, HSA, sucrose, etc.) and are often lyophilized with a minimum amount of salt. As a result, the small amounts of protein can be deposited on the vial during lyophilization as a thin and, sometimes, invisible film. Before opening, we recommend centrifuging each vial in a microcentrifuge for 20-30 seconds to drive any protein that may be lodged in the cap or on the side to the bottom of the vial. Our quality control procedures assure that each vial contains the correct amount of product.
  • What is the relationship between the specific activity expressed as an ED50 and as units/mg?
    • The ED50 is defined as the cytokine concentration at which the activity is 50% of the maximum response. This method of expressing potency should only be used for cytokines whose dose-response curves are sigmoidal in shape. The formula for converting the activity as an ED50 in ng/ml to specific activity in units/mg is:

  • Which cytokines show cross-species activity?
    • With a few exceptions, most human cytokines are active on mouse cells. Many mouse cytokines are active on human cells, but may show lower specific activity than the corresponding human cytokine. A few human cytokines, such as IL-7, even exhibit higher specific activities on mouse cells than do the corresponding mouse cytokines. The interferons, GM-CSF, IL-3, and IL-4 are known to be species-specific with very little, if any, activity on non-homologous cells. In contrast, the FGF's and neurotrophins are very highly conserved and show excellent activity on cells of other animal species.

Anti Cytokine Antibodies - Faqs

Questions pertaining to BioGems' line of Affinity Purified Anti Cytokine Antibodies.