Highly sensitive and label-free detection of the prostate specific antigen (PSA) remains a challenge in the diagnosis of prostate cancer. Here, a novel three-dimensional (3D) electrochemical immunosensor capable of sensitive and label-free detection of PSA is reported. This unique immunosensor is equipped with a highly conductive graphene (GR)-based gold (Au) composite modified electrode. The G...

Using a Au nanoparticle/reduced graphene oxide composite (AuNP-RGO), a signal-enhanced electrochemical immunosensor without label was created to detect neuron-specific enolase (NSE). Furthermore, an environmentally-friendly method was developed to prepare AuNP-RGO by employing chitosan (CS), which served as reducing and stabilizing agent. We showed that the sensitivity of the immunosensor desig...

Nano-Au and methylene blue (MB) were assembled layer-by-layer (LBL) into films on the glassy carbon electrode modified by thiourea for detection of human chorionic gonadotrophin (HCG). The electrode modification process was characterized by cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS) and scanning electron micrograph (SEM). The factors influencing the performance of the...

A sensitive electrochemical immunosensor was developed for detection of alpha-fetoprotein (AFP) based on a three-dimensional nanostructure gold electrode using a facile, rapid, "green" square-wave oxidation-reduction cycle technique. The resulting three-dimensional gold nanocomposites were characterized by scanning electron microscopy and cyclic voltammetry. A "sandwich-type" detection strategy...

A cheap and portable electrochemical immunosensor based on the silver-enhanced colloidal gold electrochemical stripping technique and gold nanoclusters (AuNCs) labels was proposed for the detection of human IgG. Inspired by adhesive proteins that secreted by marine mussels, the stable and robust film-poly (dopamine) was used to immobilize biomolecules (Ab1) on an indium tin oxide (ITO) electrod...

A disposable electrochemical immunosensor for carcinoembryonic antigen (CEA) was proposed based on the antigen immobilized in a colloidal gold nanoparticles modified chitosan membrane on the surface of an indium-tin oxide (ITO) electrode. The different membranes were characterized by scanning electron microscope and electrochemical methods. Based on a competitive immunoassay format, the immobil...

We describe the fabrication and characterization of components of a biosensor system that can be used for simultaneous screening of multiple pathogens in a sample. The two sub-systems are: (1) a mixed antibody immunosensor based on molecular biowires and (2) a multi-channel potentiostat for measuring conductance across the immunosensor. The immunosensor operates by converting binding events bet...

A facile one-step electrochemical reduction method was developed to prepare electrochemically reduced graphene oxide (ERGO) and gold-palladium bimetallic nanoparticles (AuPdNPs) as the platform of immunosensor. A novel competitive electrochemical immunosensor was then proposed by combining the ERGO-AuPdNPs platform with silver nanoparticles (AgNPs) functionalized polystyrene bionanolabel for th...

CD105 is a well-known tumor metastasis marker and useful for early monitoring of metastasis and cancer relapse. It is important to generate rapid, reliable and precise analytical information regarding CD105 levels. To establish a simple, selective and sensitive detection method, we prepared an immunosensor with novel bioconjugates based on Pt nanoparticles, thionin acetate and antibodies. The p...

Anti-HER-3 antibody was used for the first time in a disposable immunosensor based on indium tin oxide (ITO) substrate for HER-3 quantification. Anti-HER-3 was immobilized onto ITO substrate by 3-aminopropyl)triethoxysilane (APTES) and glutaraldehyde. This highly sensitive immunosensor was capable of detecting concentrations of HER-3 down to the femtogram/ml level by investigating changes in th...