Biomedical Engineering Reference
In-Depth Information
and blocking buffer (Ocean catalog # BBB). The QD-based fluorescent detection
of mouse IgG proteins were stable at 4 °C even after 48 h of storage. These pre-
liminary results show great promise for application in clinical diagnosis of disease
biomarkers from cancer, heart disease, and from infectious disease agents.
Rare-earth-doped β-NaYF
4
:Yb,Er upconversion NPs were synthesized and
coated with a thin layer of SiO
2
to form core−shell NPs that were further modi-
fied with amino groups.
55
The amino group was used to covalently attach rabbit
anti-CEA8 antibodies that were used as fluorescent biolabels for the detection
of CEA. CEA is a cancer biomarker expressed on the surface of HeLa cells that
was detected under 980-nm NIR excitation and enabled the fluorescent imaging
and detection of the HeLa cells. With proper cell-targeting or tumor-homing
peptides or proteins conjugated, the NaYF
4
:Yb,Er NPs can find potential appli-
cations in the in vivo imaging, detection, and diagnosis of cancers.
NMs consisting of aniline monomer polymerized around gamma iron(III)
oxide (γ-Fe
2
O
3
) cores were used in a direct-charge transfer biosensor for the
detection of hemagglutinin A (HA) from the Influenza A virus (FLUAV) H5N1
(A/Vietnam/1203/04).
165
The NMs were functionalized with antibodies against
HA and were used for the immunomagnetic separation of HA from mouse
serum matrix. CV was able to detect HA at 1.4 µM in 10% mouse serum, with
high specificity for H5 as compared to H1 (H1N1 A/South Carolina/1/18).
An AuNP/multiwalled carbon nanotube (MWCNT) layer deposited on Au
electrode was used for the carbodiimide covalent immobilization of uricase.
166
Uric acid was detected by oxidation of enzymically generated H2O2 at 0.4V
with optimal response within 7 s at 40 °C in 50 mM Tris-HCl buffer (pH 7.5).
The biosensor exhibited a linear working range of 0.01-0.8 mM with an LOD at
0.01 mM. The uric acid levels in serum of healthy individuals and persons suffer-
ing from gout were measured with the sensor giving 98.0 and 96.5% correlation
with the analytical recoveries of the added uric acid, 10 and 20 mg/L, respectively.
The sensor exhibited a shelf life of 120 days and was used in more than 200 assays.
4.8.3 Whole-Cell Nanobiosensors
The evolution of NMs is opening new prospects for exploring individual liv-
ing cells allowing for evaluation of chemical species in specific locations.
The use of these NMs could provide the basis for ultrasensitive nanoscale
detection of cells. Proper interfacing of biological recognition events is neces-
sary for signal transduction that may involve electrochemical or optical sig-
nal transduction. NMs can provide excellent solutions to meet biointerfacing
requirements, owing to their tailorable physical and chemical properties by
varying size, composition and shape at the nanoscale.
5,167,168
NMs are very
effective in sensing of whole cells that includes human cells and bacterial
cells for in vitro diagnosis. The unique properties of NMs that exhibit optical,
electronic, and other unique physical properties provide effective sensing of
whole cells at very low levels
