BOC Sciences offers gold nanoparticles labeled antibodies based on a comprehensive state-of-the-art platform. These antibodies can be monoclonal antibodies, polyclonal antibodies, specific antibodies as well as directed antibodies.
The principle of antibody labeling with gold nanoparticles is based on the highly specific binding properties of antibodies and the excellent optical properties of gold nanoparticles. Gold nanoparticles can be chemically modified to enable them to bind to antibodies. Gold nanoparticles labeled antibody is basically prepared by using antibodies at their isoelectric point, which can be easily adsorbed on the surface of the nanoparticle under the action of electrostatic force, and incubating them with a high concentration of antibody and gold nanoparticle solution. Once the antibody binds to the gold nanoparticles, the optical properties of the gold nanoparticles will change and the target molecule or cell can be detected and localized by light microscopy, fluorescence microscopy or other detection methods. In the process of labeling antibodies with gold nanoparticles, antibodies with high affinity and specificity are usually selected, which can be monoclonal or polyclonal antibodies.
Fig.1 Highly functional antibody-gold nanoparticle conjugates. (Okyem et al., 2021)
BOC Sciences can label gold nanoparticles with antibodies using advanced chemistry and technology. Gold nanoparticles are available in a variety of sizes and properties to suit different research needs. Customized special antibodies (5-15nm type antibodies) according to user needs are also available.
Initial assessment of the quality of gold nanoparticle labeled antibodies can be performed by simply looking at the color of the solution after each step. Gold nanoparticles have a unique visible color that changes as the particles aggregate, and simply monitoring the solution color provides a good initial assessment of success. Functional testing of labeled antibodies can also be performed to determine labeling efficiency.
Many of the steps in the conjugation protocol can be adapted and optimized for specific antibodies and assay applications. When starting any new coupling or assay, a variety of relevant parameters need to be examined to improve the performance of the antibody gold nanoparticle conjugates.
a. Reaction buffer screening - Since each antibody and each assay is unique, buffer conditions may be specific to the antibody being used.
b. Antibody loading - The percentage of antibody that is conjugated to the nanoparticles needs to be titrated to improve performance and conserve reagents if necessary. First, the nanoparticles are conjugated to 3 different amounts of antibody. Then the optimal loading volume is selected and the ratio around that concentration is further titrated to select the optimal conditions.
c. Antibody incubation time - Typically, antibodies require a minimum incubation time of 30 minutes to 2 hours at room temperature to couple to nanoparticles. Longer and shorter incubation times at different temperatures can be evaluated for better conjugate stability and performance.
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