Biomedical Engineering Reference
In-Depth Information
Biosensors can incorporate two types of “smart” materials. These are: (a) “passive”
materials which have unusual properties that can enhance significantly the functional
properties of the sensing layer such as providing faster response and stabilization of the
biological components and (b) stimuli-responsive materials (StRMs) which themselves
respond to changes in the environment and in some cases may act as switches to turn the
biosensor response on or off. The ultimate goal may be to achieve a level of biomimetics
that approaches the sensing capabilities of living cells. A classification of the materials
used for biosensor design is presented in Table 7.1. Figure 7.1 shows some examples of
these materials, which include conducting polymers, smart fabrics and textiles, den-
drimers, carbon nanotubes, and pH-, temperature- or photo-responsive polymers or
hydrogels. Other materials that can be potentially utilized or are being reported for novel
TABLE 7.1
Classification of “Smart” Materials in Biosensor Design
Material Type
Examples
Advantages
Passive Materials
Inorganic Materials
Conducting organic and
High electrical conductivity
polymeric materials
Thin films
Dendrimers
Custom designed with
specific properties
Star-shaped or many other
configuration
Ferromagnetic particles
Can be applied in label-free
detection
Stimuli Responsive Materials
Shape-sensitive alloys
High-temperature
applications
Long term stability and
robustness
PH-sensitive polymers
Operate under mild
conditions
Temperature-sensitive polymers
Versatile
Photosensitive polymers
Easy processing and
incorporation
Rheological fluids
High-pressure applications
Smart fabrics
and textiles
Cantilever arrays
Conducting gels
Ferro-magnetic
particles
Dendrimers
BIOSENSOR
SENSING LAYER
Stimuli-responsive
materials
Nanotubes
FIGURE 7.1
Examples of “smart” materials and tech-
nologies in biosensor design.
Nanoparticles and microspheres
