432
R. Mankamna Kumari et al.
Photoacoustic imaging is used in the biomedical field for imaging the biological
tissues by using non-ionizing laser pulses (De La Zerda et al. 2008). It provides
higher spatial resolution and allows deeper tissues to be imaged compared to the most
optical bio-imaging techniques. There are many diseases which do not show natural
photoacoustic agents especially in the early stages. So in these cases it becomes a
necessity to administer some photoacoustic agents from outside for better imaging.
There are a number of photoacoustic agents available. However, they do not exhibit
proper targeting to a diseased site in living subjects (De La Zerda et al. 2008). Singlewalled carbon nanotubes conjugated with cyclic Arg-Gly-Asp (RGD) peptides are
the potent contrasting agent for photoacoustic imaging of tumors. Mice bearing
tumors were injected intravenously with these modified targeted carbon nanotubes
showed photoacousting signals to be eight times better than mice injected with nontargeted nanotubes (De La Zerda et al. 2008). The results were cross checked ex vivo
by using Raman spectroscopy. Hence, the photoacoustic imaging of targeted singlewalled carbon nanotubes can be used in non-invasive cancer imaging and monitoring
of nanotherapeutics in living subjects.
Carbon nanotubes are good at biosensing. It provides specific sensing of wide
variety of biological species. It performs sensing operation without the use of any
labels or complex reaction schemes. Single-walled carbon nanotubes provide optical
detection of DNA conformational polymorphism (Heller et al. 2006). There is a
synthetic approach which uses cell free synthesis on to SWCNT for the production
of label free protein microarray capable of single protein detection (Ahn et al. 2011).
These are used for detection of single molecules as well.
4.4 Quantum Dots
Quantum dots (QDs) are tiny semiconductors that are few nanometers in size. They
show wide electronic and optical properties which differ from the LED particles.
These quantum dots when excited by electricity or light, emits light at the frequencies
that can precisely be tuned by changing the dot’s size, shape material, enabling myriad
application.
Quantum dots are one of the most vital and fascinating nanomaterial among several metallic NPs that are involved in biomedical application. They have been focused
on potential applications in cancer diagnosis and therapy. These are frequently used
in bioimaging of living cells and tissues as bio probes or labels (Onoshima et al. 2015)
and incorporated in various biological assays for reversible detection and quantification of biomolecules. These assays are based on distance-dependent fluorescence
resonance energy transfer (FRET) and multiplexed bioanalysis with multiple colors.
It is further utilized in immunoassays, molecular diagnosis, clinical analysis, and
cellular analysis (Onoshima et al. 2015).
QDs help in biological imaging and cellular studies but the toxic nature of cadmium is the major concern. The recent advancement developed the cadmium-free
quantum dots. This made easy in vitro and in vivo bio-imaging studies. The cellular
R. Mankamna Kumari et al.
Photoacoustic imaging is used in the biomedical field for imaging the biological
tissues by using non-ionizing laser pulses (De La Zerda et al. 2008). It provides
higher spatial resolution and allows deeper tissues to be imaged compared to the most
optical bio-imaging techniques. There are many diseases which do not show natural
photoacoustic agents especially in the early stages. So in these cases it becomes a
necessity to administer some photoacoustic agents from outside for better imaging.
There are a number of photoacoustic agents available. However, they do not exhibit
proper targeting to a diseased site in living subjects (De La Zerda et al. 2008). Singlewalled carbon nanotubes conjugated with cyclic Arg-Gly-Asp (RGD) peptides are
the potent contrasting agent for photoacoustic imaging of tumors. Mice bearing
tumors were injected intravenously with these modified targeted carbon nanotubes
showed photoacousting signals to be eight times better than mice injected with nontargeted nanotubes (De La Zerda et al. 2008). The results were cross checked ex vivo
by using Raman spectroscopy. Hence, the photoacoustic imaging of targeted singlewalled carbon nanotubes can be used in non-invasive cancer imaging and monitoring
of nanotherapeutics in living subjects.
Carbon nanotubes are good at biosensing. It provides specific sensing of wide
variety of biological species. It performs sensing operation without the use of any
labels or complex reaction schemes. Single-walled carbon nanotubes provide optical
detection of DNA conformational polymorphism (Heller et al. 2006). There is a
synthetic approach which uses cell free synthesis on to SWCNT for the production
of label free protein microarray capable of single protein detection (Ahn et al. 2011).
These are used for detection of single molecules as well.
4.4 Quantum Dots
Quantum dots (QDs) are tiny semiconductors that are few nanometers in size. They
show wide electronic and optical properties which differ from the LED particles.
These quantum dots when excited by electricity or light, emits light at the frequencies
that can precisely be tuned by changing the dot’s size, shape material, enabling myriad
application.
Quantum dots are one of the most vital and fascinating nanomaterial among several metallic NPs that are involved in biomedical application. They have been focused
on potential applications in cancer diagnosis and therapy. These are frequently used
in bioimaging of living cells and tissues as bio probes or labels (Onoshima et al. 2015)
and incorporated in various biological assays for reversible detection and quantification of biomolecules. These assays are based on distance-dependent fluorescence
resonance energy transfer (FRET) and multiplexed bioanalysis with multiple colors.
It is further utilized in immunoassays, molecular diagnosis, clinical analysis, and
cellular analysis (Onoshima et al. 2015).
QDs help in biological imaging and cellular studies but the toxic nature of cadmium is the major concern. The recent advancement developed the cadmium-free
quantum dots. This made easy in vitro and in vivo bio-imaging studies. The cellular