Introduction Cholesterol oxidase (CO, EC 1.1.3.6) is a flavoenzyme which catalyzes the first step in the pathway of cholesterol degradation in various microorganisms. CO is a bifunctional enzyme: it catalyzes the oxidation of ß-hydroxysteroids and the isomerization of the produced [\s-ketosteroid to the [\4-3-ketosteroid. The three dimensional structure of CO from Brevibacterium, which contains...

This paper describes the surface modification of TiO2 with 3-aminopropyltriethoxysilane (APTES) followed by covalent attachment of Ru-based N719 dye molecules to TiO2 through an amide linkage for use as photoanodes (PAs) in dye-sensitized solar cells (DSSCs). Attenuated total reflectance-Fourier transform infrared spectroscopy (ATR-FTIR) confirms the surface chemistry between the TiO2 and dye. ...

Bioactive constructs to guide cellular mobilization and function have been proposed as an approach for a new generation of biomaterials in functional tissue engineering. Adult mesenchymal stem cells have been widely used as a source for cell based therapeutic strategies, namely tissue engineering. This is a heterogeneous cell population containing many subpopulations with distinct regenerative ...

Vascular endothelial growth factor (VEGF) is known to activate proliferation, migration, and survival pathways in endothelial cells through phosphorylation of VEGF receptor-2 (VEGFR-2). VEGF has been incorporated into biomaterials through encapsulation, electrostatic sequestration, and covalent attachment, but the effect of these immobilization strategies on VEGF signaling has not been thorough...

In hepatobiliary disease and biliary obstruction, bilirubin often becomes covalently bound to albumin circulating in serum, producing a nondissociable complex. To determine how long this complexed bilirubin remains in the circulation, we compared the metabolic clearance of bilirubin-albumin complexes with the clearances of free bilirubin and unmodified albumin. Radiolabeled bilirubin, albumin, ...

To resolve the controversy over the functionalization effect on conductivity, we systematically investigate the structural and electronic properties of graphene covalently functionalized with phenyl groups. Using first-principles calculations combined with the model Hamiltonian analysis, we find that the structural stability, electronic and transport properties of the functionalized graphene ar...

There is a large interest in the use of nucleic acids covalently bound to surfaces for a variety of biomedical uses: biosensors, microarrays, drug delivery, lab-on-chip devices, and gene therapy, etc. Most of these applications require the covalent attachment of oligonucleotides via specific reactive groups on both modified oligonucleotide and/or surface. The purpose of this chapter is to provi...

The attachment of mouse immunoglobulin G (IgG) and anti-mouse IgG antibodies onto carbon nanotubes (CNTs), using either non-covalent or covalent means was investigated. The resultant CNTs were characterised using a variety of techniques including enzymelinked and fluorescence-linked immunoassays, UV-visible-NIR and Raman spectroscopy, transmission electron microscopy and cyclic voltammetry. TEM...

Procion Yellow M-4R8, an intracellular neuronal marker, has been shown to bind covalently to the subcellular organelles of rat brain under physiologic conditions. Binding to purified proteins, nucleic acids and lipids also occurs under such conditions, the probable site of attachment being the primary amino group. Lipid membranes were highly impermeable to this dye. The fluorescence intensity o...

A versatile two-step method has been developed that allows linking of biomolecules covalently to hydrogen-terminated group-IV semiconductors by means of epoxy-alkenes. First, the terminal C==C double bond of the alkene forms a covalent bond with the silicon, germanium, or diamond surface by UV-mediated hydrosilylation. The terminal oxirane moiety then reacts with the biomolecule. As a model sys...