Biomedical Engineering Reference
In-Depth Information
8
Molecular Film Assembled Detection System for
Biosensors by Layer-by-Layer Adsorption
Shin-ichiro Suye and Haitao Zheng
CONTENTS
8.1 Introduction ................................................................................................................................223
8.2 Preparation of Layer-by-Layer Film on a Solid-State Device ..........................................224
8.3 Properties of Layer-by-Layer Film ..........................................................................................225
8.3.1 Characterization of Multicomponent Films by Quartz Crystal Microbalance 225
8.3.2 Atomic Force Microscopy ..........................................................................................227
8.4 Application of Layer-by-Layer Adsorption for Biosensors ..............................................227
8.5 Conclusions ................................................................................................................................228
References ..............................................................................................................................................229
8.1
Introduction
Enzymatic biosensors have been extensively applied in clinical, food, and environmental
areas as an analytical instrument with fast detection speed, high selectivity and sensitivity.
The construction of functional protein- or mediator-containing layers is important for
biosensors because the immobilization procedure of enzyme and mediator should be bene-
ficial to electron transfer between enzymes and electrode surface by facilitating redox medi-
ator activity [1]. Modification of a solid surface has become a major challenge in the area of
materials science. This modification allows the adjustment and control of parameters such
as binding and frictional properties, biocompatibility, conductivity, and adhesion of a solid
surface. The deposition of single layers on the surface offers the opportunity to manipulate
surface properties at the molecular level, and multilayer films, consisting of organic com-
pounds on a solid surface, have been the focus of materials science for more than several
decades. In all research works, the control of layer thickness, sequence, density, and rough-
ness is critical. Various approaches have been utilized to immobilize protein on a modified
electrode surface. Although some achievements have been made by the Langmuir-Blodgett
method and molecular self-assembly (chemisorption from solution), this method is not
widely used for protein immobilization, because water-soluble proteins seem difficult to
spread on the air-water surface, and are denatured easily at the interface [2].
223
