Creative Diagnostics provides contract ELISA development kit services for the R&D and IVD community. We conduct ELISA kit development services for supporting regulatory approval submission. Creative Diagnostics will carry out the approval proposal and deliver the expected results and documents in a time and cost effective manner.
Our staff scientists follow rigorous guidelines for quality control with a focus on thorough optimization and validation of every aspect of assay development, including antibody specificity, assay sensitivity, reproducibility (intra- and inter-assay), cross-reactivity, standard curve range, assay accuracy (linearity and recovery) and kit stability.
Through combined expertise in antibody generation and immunoassay development, we have produced a large number of diagnostic antibodies that cover a wide range of disease portfolio including infectious diseases cardiovascular diseases, cancer and bone diseases, with osteoporosis in particular.
Immunoassay Service Formats:
› Direct ELISA
The direct ELISA uses the method of directly labeling the antibody itself. Microwell plates are coated with a sample containing the target antigen, and the binding of labeled antibody is quantitated by a colorimetric, chemiluminescent, or fluorescent end-point. Since the secondary antibody step is omitted, the direct ELISA is relatively quick, and avoids potential problems of cross-reactivity of the secondary antibody with components in the antigen sample. However, the direct ELISA requires the labeling of every antibody to be used, which can be a time-consuming and expensive proposition. In addition, certain antibodies may be unsuitable for direct labeling. Direct methods also lack the additional signal amplification that can be achieved with the use of a secondary antibody.
› Sandwich ELISA
The sandwich ELISA measures the amount of antigen between two layers of antibodies. The antigens to be measured must contain at least two antigenic sites, capable of binding to the antibody, since at least two antibodies act in the sandwich. For this reason, sandwich assays are restricted to the quantitation of multivalent antigens such as proteins or polysaccharides. Sandwich ELISAs for quantitation of antigens are especially valuable when the concentration of antigens is low and/or they are contained in high concentrations of contaminating protein. Creative Diagnostics has successfully applied our proprietary technologies which can expedite development of ELISA with certain throughput and low cost. The ELISA kits are good enough to reach detection sensitivity at sub-femtogram per ml level and are useful for screening protein targets and quantifying their expression in different conditions.
› Competitive ELISA
This type of ELISA is frequently used for the detection of small analyte antigens containing a single epitope. Typically the plate is coated with antibody specific for the single epitope on the analyte. Next, free analyte and analyte ligated to a detection enzyme are incubated on the coated plate. The quantity of the enzyme-ligand conjugate bound to the plate is detected after incubation with an appropriate substrate and the resulting signal measured with a microplate reader. In this type of ELISA, there is an inverse relationship between the signal obtained and the concentration of the analyte in the sample, due to the competition between the free analyte and the ligand-enzyme conjugate for the antibody coating the microplate, i.e. the more analyte the lower the signal.
› Immuno-Capture Enzymatic Assay
1. Light absorbance
2. Fluorescence intensity or polarization
3. Fluorescence resonance energy transfer
1. Feasibility assessment and assay design
2. Assay optimization
3. Assay Validation