Biomedical Engineering Reference
In-Depth Information
carboxyl, streptavidin, benzaldehyde, and Ni-NTA for Histidine-tagged Protein A and
Protein G for coupling antibodies. This was the first company that introduced the
3D biosensor surface for label-free biomolecular interaction analysis. The company
indicates that their biosensor permits high throughput ranking in multiwall plates, and
data-rich kinetic measurements in flow cells, using a single reader instrument and the
same chemistry. The company emphasizes that its sensor permits the measurements of
slow off-rates which are not measurable by traditional SPR biosensors.
(f)
Uludag et al. (2010)
have recently indicated that nucleic acid based recognition of
viral sequences may be used for the rapid and accurate confirmation of viral infection.
This is done using label-free biosensing. The authors indicate that gold nanoparticles
may be used to enhance detection sensitivity. Quartz crystal microbalance biosensors may
be used upon surfaces where nanoparticle oligonucleotides conjugates are complementary
to surface-immobilized ss DNA probes. The authors indicate that their signal amplification
assays may be used for the detection of specific DNA sequences of Herpes Simplex Virus
(HSV) type 1.
More importantly, the authors developed the biosensor to understand the influence of mass
transport in the flow cell (which incidentally is one of the major themes of this topic), and the
binding kinetics of targets to nanoparticles in solution. Other parameters analyzed include the
binding geometries of the targets in the nanoparticle, and the packing of nanoparticles on the
surface. All of this points to the influence of the biosensor surface characteristics, and how it
may influence the binding kinetics. This is in fact one of the major themes of the topic wherein
the degree of heterogeneity on the biosensor surface is characterized by a fractal dimension, and
how this fractal dimension influences the binding and dissociation kinetics.
The authors conclude by indicating that their analytical model permitted the determination of
optimal nanoparticle diameter, concentration, and probe density. Their results were based on
both numerical analysis as well as on subsequent associated experimental data. They further
emphasize that their analysis suggests that the proximal contact area between the particle and
the sensor surfaces, and the available capture area of the particle and the binding dynamics to
this capture area very significantly influence the detection limit.
(g) Some of the more recent biosensor applications were presented at Biosensors 2010 held
com
). Some of the more interesting ones include:
1. Direct detection of drugs in serum with an electrochemical aptamer-based biosensor
(
Rowe and Plaxco, 2010
)
2. The development of a novel theranostic platform for cytotoxicity evaluation of
amyloid-forming neurodegenerative causative proteins (
Kim et al., 2010
)
3. Theranostic biochips—from biosensors to personalized medicine (
Bachmann, 2010
)
