Fabrication of Layer-By-Layer-Assembled Bio-Architecture on Gold Nanorods

Abstract

We have successfully fabricated a layer-by-layer (LBL)-assembled functional bio-architecture on gold nanorod substrates with an increased number of immobilized biomolecules. The vertical array of gold nanorods was fabricated through an electrochemical process, using porous aluminum oxide as a template and the dispersed lm of gold nanorods was prepared by using the Langmuir-Blodgett technique. Horse radish peroxidase was immobilized on the vertical array and on the dispersed lm of gold nanorods through LBL assembly by using the speci c interaction between avidin-biotin molecules. The levels of catalytic activity of the LBL-assembled bio-architectures fabricated on both the vertical array and the dispersed lm of gold nanorods were, respectively, 2.8 and 1.5 times better than that of the at gold surface due to an increase in surface area and ease of substrate accessibility. Scanning electron microscopy (SEM) and uorescence images clearly show a regular, successively well-controlled LBL-assembled bio-architecture with a bilayer structure of proteins on gold nanorods. This controlled fabrication of biologically active enzymes on gold nanorod structures via LBL assembly demonstrates a technique for the development of bio-functional molecular devices with enhanced sensitivities and fast response time.