- Are your fluorescently labeled antibodies beginning with catalog # FAB just the Fab fragments?
- FAB is our naming convention. This does not mean that these antibodies are just the Fab fragments. Unless otherwise indicated on the product datasheet, they are whole, IgG antibodies.
- Can I measure the concentration of a fluorochrome-conjugated antibody using an A280 reading?
- The A280 reading of a fluorochrome-conjugated antibody is affected by the fluorochrome as well as by the buffer used to prepare the conjugate. A simple A280 /E280 measurement will not accurately reflect the concentration of the conjugated antibody. The concentration can be found on the lot specific Certificate of Analysis (CoA) for all Bio-Techne fluorochrome-conjugated antibodies.
- Does trehalose interfere with metal conjugation to antibodies, for CyTOF?
- Trehalose is not reported to interfere with metal conjugation of antibodies, for CyTOF
- What Fc blocking reagent does R&D Systems recommend for Flow Cytometry?
- The Fc blocking reagent ideally should be IgG from the same species as the cells which are being stained.
- What is R&D Systems doing to reduce its use of packaging from non-renewable resources?
- Environmental stewardship is important to R&D Systems and its employees. R&D Systems is ISO 14001:2015 Certified and as part of this we are continuously reviewing our sustainability practices and "green" options. First and foremost, the energy expended to ship back the styrofoam box is more detrimental to the environment than having the facility re-use or recycle it. Our stance is to encourage our customers to implement a recycling program locally. At R&D Systems we have chosen to reduce the use of styrofoam as much as possible by: doing extensive stability testing in order to determine which products can be shipped with minimal packaging at ambient temperatures, converting the use of non-recyclable packaging materials to recyclable plastics, cardboard, or biodegradable materials, and continuing to investigate alternatives to dry ice shipments, the use of re-usable containers, and gel packs that allow for smaller styrofoam containers. Employees were key to initiating a recycling program at our facilities. Internally, we recycle paper, plastic, cardboard, aluminum, and glass.
- What is the molecular weight of Fluorescein Isothiocyanate (FITC)?
- The molecular weight of FITC is 389.38 Daltons. However, R&D Systems uses 5- (and 6-) Carboxyfluorescein (CFS) for antibody conjugation, which has a molecular weight of 473 Daltons.
- What is the molecular weight of R-Phycoerythrin (PE) ?
- PE is a 240 kDa protein with 23 phycoerythrobilin chromophores per molecule. Typically, only one PE molecule is conjugated to an antibody.
- What type of tubes do you suggest using for staining in flow cytometry?
- We reccommend the use of Falcon™ polystyrene tubes.
- Why does the Biotinylated Fluorokine® kit protocol say not to wash the cells after adding the Fluorokine reagent?
- This kit is designed to perform an amplification reaction. It is extremely important not to wash the cells before adding the avidin-FITC reagent. When the Fluorokine is added to the cells, some of it binds to receptors on the cell surface, and some remains as excess in the solution. When the avidin-FITC reagent is added to the reaction, some of it will bind to the biotinylated Fluorokine which has bound to the cell surface receptors. However, since each avidin-FITC molecule has the ability to bind 4 biotin molecules, the avidin-FITC bound to the surface of the cell also binds to some of the excess Fluorokine in the solution, which then binds more avidin-FITC in a cascade of reactions. This amplification reaction does not increase background staining, nor does it compromise the specficity of the reaction. It does mean that Biotinylated Fluorokine kits are less quantitative than flow cytometry performed with a specific antibody, but the benefits are that you can detect very low levels of receptors and you can detect all receptors that bind the biotinylated cytokine provided in the kit.