ELISAs would be easier without having to deal with secondary antibodies. Image from http://en.wikipedia.org/wiki/File:ELISA.jpg
Imagine being able to do your Western blots, ELISAs and immunohistochemical reactions without fiddling around with finicky secondary antibodies. How cool would that be? In a paper recently out in the Journal of the American Chemical Society, researchers have come up with a new molecule that can detect proteins without relying on secondary antibodies. “This will greatly move the protein detection forward, impacting a variety of fields, such as biosensing and diagnostics, anything related to protein detections,” says Dan Luo of Cornell University who spearheaded the work.
The molecule, which Luo and colleagues call the universal adaptor, has two parts to it: an antibody-binding component and a DNA tag. The antibody component is derived from an engineered variant of protein A, which binds to most types of IgG primary antibodies. The DNA tag can hybridize to DNA-modified reporter molecules that give off signals, such as DNA nanobarcodes, quantum dots and enzymes.
When the universal adaptor is used with an IgG primary antibody in an experiment, the antibody component of the adaptor latches onto the primary antibody. The DNA tag attaches to a chosen reporter molecule, such as horseradish peroxidase, and labels the primary antibody.
There are two main benefits to the universal adaptor, says Luo. First, researchers are no longer limited to the relatively few commercially available primary and secondary antibody pairs. They can also use several primary antibodies in their experiments, throw in the universal adaptor, and use a variety of reporter molecules to get multiplexed detection without having to worry about secondary antibodies inadvertently crossreacting with the wrong primary antibody. The second benefit is that the DNA portion of the hybrid molecule lends itself to amplification, which means signals from experiments can be turned up for easier detection.
