428
R. Mankamna Kumari et al.
concept of this assay relies on the release of AuNPs by oxidative metal dissolution
and indirect determination of the HBr solubilized Au(III) ions by anodic stripping
voltammetry. HBr/Br 2 is highly toxic in nature. So to avoid it, direct electrochemical
detection tags were developed (Boisselier and Astruc 2009).
Furthermore, AuNPs are implemented as new contrasting agents for magnetic resonance imaging (MRI). Here AuNPs work as the templating carriers for the gadolinium chelates that are currently used in the clinical diagnosis. The sensitivity of MRI
is increased by using the AuNPs along with iron oxide. The gold shell of the particle
provides the optical properties and the core of iron oxide will give magnetism (Boisselier and Astruc 2009). In addition, these particles possess an excellent property of
fluorescence. This behavior of gold nanoparticle is vitally used in the fluorescence
correlation spectroscopy (FCS) and fluorescence microscopy. The fluorescence of
AuNPs carries the eminent behavior of anti-photobleaching under strong light illumination. It gives a new cell imaging method. The cells are stained with AuNPs and
illuminated under strong light. The florescence of AuNPs on the cell membrane and
inside the cell is collected for the cell imaging.
Forensic researchers are making continuous efforts for enhancing the methods for
detecting finger prints. Saunders introduced the use of AuNPs in detection of fingerprint and later Schnetz and Margots improved the idea. The colloidal of AuNPs of
low pH is used for getting fingerprint present on the substrate. It acts by the mechanism of electrostatic attraction as when the substrate with fingerprint is immersed in
the colloidal gold, the particles start bounding to print and later the bound particles
are enhanced by catalytic deposition of metallic silver (Wilson 2008).
4.2 Silver Nanopartcles
The widespread use of silver NPs in various fields, including medical, food, health
care, and industrial purposes are due to their unique chemical and physical properties.
Silver NPs have capability of cellular imaging in vivo. It is widely investigated in
studying inflammation, tumors, immune response, and the effect of stem cells. The
contrast agents are conjugated or encapsulated to NPs by modifying the surface and
bioconjugation of NPs. Due to its stronger and sharper Plasmon resonance, Ag plays
an important role in imaging. Earlier nanosilver along with vanadium oxide were
used for enhancement of battery performance in next generation active implantable
medical devices (Etheridge et al. 2013; Zhang et al. 2016).
Recently silver-based biosensors are designed for the clinical detention of serum
P53 in head and neck squamous cell carcinomas. This can easily locate the cancer
cells and can absorb the light and destroy the targeted cancer cells selectively by
photothermal therapy. Silver NPs have potential usage in cancer diagnostics and
treatments. It can cause apoptosis in the cancer cells. Asharani et al. studied human
lung cells IMR-90 and brain cancer cells U251 (AshaRani et al. 2008; Zhang et al.
2016). They observed that there were cytosolic proteins attached on the surface of
the silver NPs and this may influence the function of intracellular factors which are
R. Mankamna Kumari et al.
concept of this assay relies on the release of AuNPs by oxidative metal dissolution
and indirect determination of the HBr solubilized Au(III) ions by anodic stripping
voltammetry. HBr/Br 2 is highly toxic in nature. So to avoid it, direct electrochemical
detection tags were developed (Boisselier and Astruc 2009).
Furthermore, AuNPs are implemented as new contrasting agents for magnetic resonance imaging (MRI). Here AuNPs work as the templating carriers for the gadolinium chelates that are currently used in the clinical diagnosis. The sensitivity of MRI
is increased by using the AuNPs along with iron oxide. The gold shell of the particle
provides the optical properties and the core of iron oxide will give magnetism (Boisselier and Astruc 2009). In addition, these particles possess an excellent property of
fluorescence. This behavior of gold nanoparticle is vitally used in the fluorescence
correlation spectroscopy (FCS) and fluorescence microscopy. The fluorescence of
AuNPs carries the eminent behavior of anti-photobleaching under strong light illumination. It gives a new cell imaging method. The cells are stained with AuNPs and
illuminated under strong light. The florescence of AuNPs on the cell membrane and
inside the cell is collected for the cell imaging.
Forensic researchers are making continuous efforts for enhancing the methods for
detecting finger prints. Saunders introduced the use of AuNPs in detection of fingerprint and later Schnetz and Margots improved the idea. The colloidal of AuNPs of
low pH is used for getting fingerprint present on the substrate. It acts by the mechanism of electrostatic attraction as when the substrate with fingerprint is immersed in
the colloidal gold, the particles start bounding to print and later the bound particles
are enhanced by catalytic deposition of metallic silver (Wilson 2008).
4.2 Silver Nanopartcles
The widespread use of silver NPs in various fields, including medical, food, health
care, and industrial purposes are due to their unique chemical and physical properties.
Silver NPs have capability of cellular imaging in vivo. It is widely investigated in
studying inflammation, tumors, immune response, and the effect of stem cells. The
contrast agents are conjugated or encapsulated to NPs by modifying the surface and
bioconjugation of NPs. Due to its stronger and sharper Plasmon resonance, Ag plays
an important role in imaging. Earlier nanosilver along with vanadium oxide were
used for enhancement of battery performance in next generation active implantable
medical devices (Etheridge et al. 2013; Zhang et al. 2016).
Recently silver-based biosensors are designed for the clinical detention of serum
P53 in head and neck squamous cell carcinomas. This can easily locate the cancer
cells and can absorb the light and destroy the targeted cancer cells selectively by
photothermal therapy. Silver NPs have potential usage in cancer diagnostics and
treatments. It can cause apoptosis in the cancer cells. Asharani et al. studied human
lung cells IMR-90 and brain cancer cells U251 (AshaRani et al. 2008; Zhang et al.
2016). They observed that there were cytosolic proteins attached on the surface of
the silver NPs and this may influence the function of intracellular factors which are