Here, we have measured the biospecific interaction Brefeldin A clinical between antigen and antibody with a sandwich type immunosensor using alkaline phosphatase (ALP) as the enzyme on the gold film coated nanoporous niobium oxide electrode. This allows us to determine the sensitivity of the electrochemical signal as a function of the mouse IgG concentration. Nanoporous niobium oxide offers good adhesion and a noticeable decrease in the detection limit for target molecules by amplifying the electrochemical signal via electrooxidation of p-aminophenol (AP) on the electrode. This is in part attributed to a structural stability of enzyme immobilized at the sputtered gold films and is in part to the higher roughness of the surface of the sputtered gold films. This method yields an electrochemical signal with twice the sensitivity of a bulk gold electrode.
Along with the results reported by Choi et al. [1,2], this report demonstrates that Au@Nb2O5 can be Inhibitors,Modulators,Libraries a very useful Inhibitors,Modulators,Libraries electrode, not only for DNA sensors but also as protein Inhibitors,Modulators,Libraries sensors.2.?Experimental Section2.1. Chemicals and ReagentsMouse immunoglobulin G (IgG) from serum, biotinylated goat antimouse IgG, alkaline phosphatase (ALP)-congugated goat antimouse IgG, goat IgG form serum, 4-mercaptobenzoic acid (4-MBA), and 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide hydrochloride (EDC) were obtained from Sigma. 4-Aminophenylphosphate (APP) was obtained from LKT Laboratories (Saint Paul, MN, USA). Bovine serum albumin (BSA) was purchased from Amresco Inc. (USA). The incubation buffer (IB) consisted of 50 mM Tris, 150 mM NaCl, and 1% BSA (pH 7.2).
The rinsing buffer (RB) comprised 50 mM tris, 0.5 M NaCl, 0.05% Tween 20, and 0.05% BSA (pH 7.5). The buffer for electrochemical experiments (EB) consisted of 50 mM Tris, 10 mM KCl, and 1 g L?1 MgCl2 (pH 9.0).2.2. Preparation Inhibitors,Modulators,Libraries of Anodic Nanoporous Niobium OxideThe preparation of nanoporous niobium oxide by electrochemical anodization has been described elsewhere in detail [14�C16]. In brief, Nb foil with a purity of 99.9% and a thickness of 0.25 mm (Goodfellow, UK) was cleaned by ultrasonication in acetone for 5 minutes, washed with ethanol and dried with a stream of N2 gas. Anodization was carried out at a constant voltage of 2.5 V in the mixture of 1 wt.% HF + 1 M H3PO4 at room temperature for 1 h, using a potentiostat/galvanostat (AutoLab PGSTAT12, Eco Chemie) interfaced to a computer.
The cell was a three-electrode system consisting of a Pt mesh acting as the counter electrode, Ag/AgCl/3M KCl as the reference electrode and an Nb foil with a size of 1 cm2 as the working electrode. During the anodization, the stirring rate of the electrolyte was kept constant (~180 rpm). AV-951 As a result, nanoporous niobium oxide with average pore diameter of 10 nm, length http://www.selleckchem.com/products/XL184.html of 120 nm and pore density of 4.6 �� 1015/m2 was prepared. FE-SEM images of the anodic porous niobium oxide can be found in the reference [16].