Detection of glucose using immobilized bienzyme on cyclic bisureas-gold nanoparticle conjugate.

A highly sensitive electrochemical glucose sensor has been developed by the co-immobilization of glucose oxidase (GOx) and horseradish peroxidase (HRP) onto a gold electrode modified with biocompatible cyclic bisureas-gold nanoparticle conjugate (CBU-AuNP). A self-assembled monolayer of mercaptopropionic acid (MPA) and CBU-AuNP was formed on the gold electrode through a layer-by-layer assembly. This modified electrode was used for immobilization of the enzymes GOx and HRP.

Synthesis and characterization of gold-chitosan nanocomposite and application of resultant nanocomposite in sensors.

Chitosan gold nanocomposite (CGNC) was synthesized in a single step process and the pH dependent properties of the composite were investigated. The structure of the polymer was pH dependent and gelation of the polymer observed at pH 4-5. Transmission electron microscopy (TEM) analysis showed that the distribution of gold nanoparticles within unit area varied with the gelation of the polymer, without affecting the size of the nanoparticles.

A novel electrochemical sensor surface for the detection of hydrogen peroxide using cyclic bisureas/gold nanoparticle composite.

A novel electrochemical sensor surface with enhanced sensitivity for the detection of hydrogen peroxide has been developed based on the layer-by-layer assembly of mercapto propionic acid (MPA), cystine-based polymethylene-bridged cyclic bisureas (CBU)/gold nanoparticle (AuNP) and horseradish peroxidase (HRP) on gold electrode. Possibility of a large number of hydrogen bonds, allowed by the chemical and sterical structure of the CBU ensures the proper immobilization of the enzyme in favorable orientation and retention of enzymatic activity. Efficient electron tunneling property of AuNP together with its electrocatalytic activity leads to higher sensitivity in the detection of H(2)O(2).