Biomedical Engineering Reference
In-Depth Information
The biosensor has been applied to the screening of a number
of real samples derived from sausages, soybeans, soy lour, and
ish meal that contain GMO.
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Genotyping of single-nucleotide
polymorphisms (SNP) in the mannose-binding lectin (MBL2) gene
has also been demonstrated.
62
The dipstick test can be completed
within 10 min and does not require specialized instrumentation
or highly trained technical personnel. However, the sensitivity
of immunochromatographic assay is signiicantly lower than
ELISA. Tamiya and coworkers have reported a gold nanoparticle-
based enhancement method for obtaining a better sensitivity
in immunochromatographic test strips.
63
In this method, AuNP-
conjugated primary antibody and the antigen are used as a sensitizer.
The antigen is captured by the secondary antibody at the test line on
the strip. As a result, gold nanoparticles accumulate at the test line,
resulting in sensitivity almost at the same level of the ELISA assay.
A simple portable system for the detection of bioanalytes
would be of high demand for a wide range of applications such as
point-of-care diagnostics as well as ield detection of pathogens.
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Recently, Neuzil and Rebound
65
integrated the LSPR detection
process into a complete, simple, palm-sized device. This system does
not require any external power supply or personal computer. The
spectrum analyzer is replaced by four pulse-powered light-emitting
diodes (LED), each with different emission spectra. The relected
light beams from all LEDs are detected by a single photodiode. Its
composite output current is demultiplexed by a four-channel lock-
in ampliier. Device performance has been demonstrated through
characterization of solutions with various RIs in real time. Due to
its small size and portability, the system may be useful for ield and
point-of-care applications.
In recent years, compact biosensors combined with microluidic
technologies have received increasing interest because they have
been shown capable to provide faster and less expensive approaches
to detect chemical and biochemical entities comparing with existing
approaches in macro scale.
66,67
Huang and coworkers have integrated
a slide-based LSPR sensor with a microluidic chip.
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Using a green
LED as a light source and a novel quadrant detection scheme, the
sensitivity of this low-cost biosensor is comparable to conventional
slide-based LSPR biosensors. Besides that, the high surface to volume
ratio of the microluidic chip enhances mass transport, resulting in
shorter assay time and lower consumption of samples and reagents.
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