Biomedical Engineering Reference
In-Depth Information
7
Material Design and Selection for Smart Biosensors
Amarjeet S. Bassi
CONTENTS
7.1 Introduction ......................................................................................................................205
7.1.1 Cantilever Arrays ................................................................................................207
7.1.2 Nanotubes ............................................................................................................209
7.1.3 Ferromagnetic Particles ......................................................................................210
7.1.4 Smart Polymer Composites, Fabrics, and Textiles ..........................................211
7.1.5 Conducting Films and Gels ................................................................................211
7.1.6 Dendrimers ..........................................................................................................212
7.1.7 Nanoparticles and Microspheres ......................................................................214
7.2 Stimuli-Responsive Materials ........................................................................................215
7.2.1 pH-Sensitive Materials ........................................................................................215
7.2.2 Thermosensitive Materials ................................................................................217
7.2.3 Photo-Responsive Materials ..............................................................................218
7.3 Conclusions and Future Prospects ................................................................................218
References ....................................................................................................................................219
7.1
Introduction
A biosensor consists of a biological detection or sensing layer in close proximity to a signal
transducer. The sensing layer contains biomolecules immobilized on the biosensor surface.
Biosensors utilize biomolecules with specific recognition and binding for the analyte of
interest. The interaction of the analyte with the sensing layer produces a signal, which is con-
verted by the transducer into a measurable response. The biomolecules can be incorporated
into the sensing layer in a biosensor in different ways. The key design goals in constructing
a biosensor are rapid response, sensitivity, selectivity, and long-term stability or reuse. These
criteria can be met by patterning the biosensor surface with a high concentration of appro-
priate biomolecules (enzymes, antibodies, or other types) in such a way which minimizes
mass-transfer limitations or partitioning effects and enhances stability of the biomolecules.
The surface should also selectively interact with the environment to filter out interferences
and nonspecific molecules from the analyte of interest. One approach in such design is to
improve the performance of the sensing layer using “smart” materials.
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