278
A. S. Shinde et al.
18 Magnetic-Sensitive Systems
Magnetic sensitive nanoparticles are primarily fabricated in such a way that therapeutic agents are encapsulated inside the magnetic core or attached to the shell, thus
functionalizing the surface. These functionalized NPs are injected into the bloodstream, positioned near the target site. Magnetic fields are applied over the target
site with the use of powerful rare earth magnets with a high gradient affecting the
particles. Here, the magnetic field captures and releases the nanoparticles at the target
site. The clinical trials by Koda et al., deliver doxorubicin hydrochloride nanoparticles, showing success for hepatocellular carcinoma [118]. This method is helpful
when the target is near the body’s surface. The strength of the magnetic field falls
off swiftly as the site deepens within the body, becomes tougher to target. Several
researchers proposed to overcome this hurdle by focusing the infected sites with the
help of implanted magnets inside the body [119]. But as the suggested method is
invasive and not systematic, its application may restrict for clinical use. Synthesis of
smaller NPs is essential for superparamagnetism to tackle the problem of magnetic
agglomeration. As the size decreases, the magnetic field may fail to guide the particles and keep them at target proximity remarkably while resisting the drag of blood
flow.
19 Ultra Sound-Sensitive Systems
The homogenous distribution of nanoparticles in the solid tumor becomes challenging as they cannot travel far away from the blood vessels to the extracellular
matrix. Thus, nanoparticles can reach and release the cytotoxic drug to the cancer
cells that are closely located to the blood vessels; hence, a minimized therapeutic
index. These nanoparticles can target and damage healthy cells due to their ability
to stay for more extended periods. Researchers have explored the use of ultrasound,
which helps to increase the permeability of the capillary walls and to press them
through the extracellular matrix; thus, enhanced delivery of drugs from nano-carriers
and improved cellular uptake. Some studies have shown 2D and 3D models where
ultrasound is used to help the nanoparticles to penetrate the solid tumor along with
the controlled release of the drug into the intracellular spaces without any alterations
in its chemical properties [120].
The main advantage of the ultrasound sensitive system is its absence of ionizing
radiation, non-invasiveness, and smooth regulation of tissue penetration depth by
tuning duty cycles, frequency, and exposure time. Ultrasound destabilizes the cell
membrane that helps to release the drug into the cytosol; thus, bypassing the degenerative endocytotic pathway. Also, low-frequency ultrasounds can be utilized to deliver
liposomal-based drugs past the skin, which helps to obstruct the progression of
melanocytic abrasions [121].
A. S. Shinde et al.
18 Magnetic-Sensitive Systems
Magnetic sensitive nanoparticles are primarily fabricated in such a way that therapeutic agents are encapsulated inside the magnetic core or attached to the shell, thus
functionalizing the surface. These functionalized NPs are injected into the bloodstream, positioned near the target site. Magnetic fields are applied over the target
site with the use of powerful rare earth magnets with a high gradient affecting the
particles. Here, the magnetic field captures and releases the nanoparticles at the target
site. The clinical trials by Koda et al., deliver doxorubicin hydrochloride nanoparticles, showing success for hepatocellular carcinoma [118]. This method is helpful
when the target is near the body’s surface. The strength of the magnetic field falls
off swiftly as the site deepens within the body, becomes tougher to target. Several
researchers proposed to overcome this hurdle by focusing the infected sites with the
help of implanted magnets inside the body [119]. But as the suggested method is
invasive and not systematic, its application may restrict for clinical use. Synthesis of
smaller NPs is essential for superparamagnetism to tackle the problem of magnetic
agglomeration. As the size decreases, the magnetic field may fail to guide the particles and keep them at target proximity remarkably while resisting the drag of blood
flow.
19 Ultra Sound-Sensitive Systems
The homogenous distribution of nanoparticles in the solid tumor becomes challenging as they cannot travel far away from the blood vessels to the extracellular
matrix. Thus, nanoparticles can reach and release the cytotoxic drug to the cancer
cells that are closely located to the blood vessels; hence, a minimized therapeutic
index. These nanoparticles can target and damage healthy cells due to their ability
to stay for more extended periods. Researchers have explored the use of ultrasound,
which helps to increase the permeability of the capillary walls and to press them
through the extracellular matrix; thus, enhanced delivery of drugs from nano-carriers
and improved cellular uptake. Some studies have shown 2D and 3D models where
ultrasound is used to help the nanoparticles to penetrate the solid tumor along with
the controlled release of the drug into the intracellular spaces without any alterations
in its chemical properties [120].
The main advantage of the ultrasound sensitive system is its absence of ionizing
radiation, non-invasiveness, and smooth regulation of tissue penetration depth by
tuning duty cycles, frequency, and exposure time. Ultrasound destabilizes the cell
membrane that helps to release the drug into the cytosol; thus, bypassing the degenerative endocytotic pathway. Also, low-frequency ultrasounds can be utilized to deliver
liposomal-based drugs past the skin, which helps to obstruct the progression of
melanocytic abrasions [121].