Ultra-High Performance Immunosensor Prepared by Glassy Carbon Electrode Modified with Nano Gold Particles and Antibody

摘要

In previous reports, we have successfully fabricated biosensors that could measure chemical species that are important in environmental monitoring, as well as metabolites that are indicators of the proper functioning of our body. The detection lower limits of these biosensors are well below the measuring limits of methods used in the public domain. We continue to expand our non-toxic sensor platform based on prior reports to develop biosensors that are capable to measure metabolites at extremely low limits for biomedical applications, such as DNAs and biomarkers for cancer detections. As a demonstrative model, we are reporting an immunosensor for the detection of human immunoglobulin G (HIgG) which is the smallest but most common anti-infection antibody that makes up of majority (75-80%) of all antibodies in human body. HIgG is also the only type of antibody that can cross the placenta in a pregnant woman to help protect the fetus. The immunosensor consists of a carbon glassy electrode modified with a layer of biocomposite sol-gel material, the biocomposite sol-gel comprises coatings of polymer (cystamine/melamine), nano Au particles, and anti-HIgG. The detection range of 10~(-5) to 10~(20) g/ml of this immunosensor is reported. The detection limit of this immunosensor is orders of magnitude more superior than any measurements reported in the literature. In addition, selectivity and stability of this biosensor are discussed.