Signal enhancement for ultrasensitive detection of versatile biomaterials using specific aptamer modified Au Nano-Complex

For early diagnosis of several diseases, highly sensitive detection technology is necessary to analyze biomarkers quantitatively at low concentrations. To develop a sensitive detection system, a well-designed probe is very critical, and it mainly consisted of several bio- and nanomaterials, such as gold (Au) and silica nanoparticles. In this study, an ultrasensitive nanoprobe for the detection of versatile biomolecules was developed by the sandwich immuno-reaction technique. The developed nanoprobe was composed of aptamer-functionalized Au nanoparticles and magnetic microparticles (MMPs). In order to enhance the detection ability of the Au probe, the orientation of antibodies was defined using aptamer-induced specific binding to the F_c region of the antibody. And target antigens could be detected by the real-time polymerase chain reaction (RT-PCR) method, which was able to measure the concentration of aptamers with Au nanoparticles. Selected targets were prostate specific antigen (PSA) and Escherichia coli O157:H7 (E. coli O157:H7). This system can be applied to the diagnosis of several diseases and environmental toxicity testing, especially for the detection of very low concentrations.