Researchers at Washington State University’s School of Mechanical and Materials Engineering have developed new approaches to increase the sensitivity of sandwich-type immunoreactions by 1000-fold and allow the visualization and quantification of target pathogens through color intensity detection. These approaches can be developed as universal signal amplification techniques and applied to the detection of a myriad of pathogens and protein biomarkers.
The researchers have developed a three-in-one nanocomposite as a novel enzyme-labeled antibody which can be easily synthesized in a one-step coprecipitation method that does not require any organic solvent or covalent modifications. An antibody-HRP-Cu3(PO4)2 nanocomposite (nanoflower) was used to replace the more commonly used HRP-conjugate antibody for the detection of E. coli and the result was a far superior detection limit to that of commercial ELISA systems. Because it is an aggregate of many antibodies and enzymes, it has very high captive ability as well as catalytic activity. This novel approach can be customized to many other hybrid systems. For example, different antibodies can serve as components of the “nanoflower” preparation in order to expand its use and detect various targets. Furthermore, different enzymes can be incorporated in order to expand the modes of detection besides colorimetric. Thus this method could potentially replace existing enzyme-labeled antibody methods in ELISA and will have significant applications in the detection of pathogenic bacterial as well as clinically relevant molecules.