Sharif Digital Repository

Convenient medical diagnostics and treatments can replace conventional healthcare procedures because of their fast and profitable applications with reduced infection risk. Meanwhile, early diagnosis of cancer is a leading research subject due to the high fatality rate of the disease and being a vital precursor in the treatment effectiveness. Electrochemical-based micro-biosensors are the best candidates for measuring particular biomarker concentrations in body fluids. To address this need, we used a simple fabrication approach to develop an effective immunosensor for the early detection of cancer, in particular prostate cancer. The carbon fibers, obtained from the electrospinning technique,... 

A label-free electrochemical biosensor was developed for the rapid detection of the matrix metalloproteinase 9 (MMP-9) biomarker on the basis of antibody immobilizing on the zinc oxide (ZnO) nanoparticle and ZnO nanorod electrodes. The charge transfer resistance (Rct) of the electrodes was used as the indicator for MMP-9 concentration, which was obtained through cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS). The ZnO nanorod-based biosensor exhibited linear behavior in the MMP-9 concentration range of 1–1000 ng/ml, which is a wider range than the available concentration ranges for most of the conventional methods. The biosensor sensitivity was 32.5 μA/(decade × cm2)... 

Cardiac troponin-I (cTnI) is a well-known biomarker for the diagnosis and control of acute myocardial infarction in clinical practice. To improve the accuracy and reliability of cTnI electrochemical immunosensors, we propose a multilayer nanostructure consisting of Fe3O4-COOH labeled anti-cTnI monoclonal antibody (Fe3O4-COOH-Ab1 ) and anti-cTnI polyclonal antibody (Ab2 ) conjugated on Au-Ag nanoparticles (NPs) decorated on a metal–organic framework (Au-Ag@ZIF-67-Ab2 ). In this design, Fe3O4-COOH was used for separation of cTnI in specimens and signal amplification, hierarchical porous ZIF-67 extremely enhanced the specific surface area, and Au-Ag NPs synergically promoted the conductivity...