Modern Advancement of Nanotechnology Over Conventional …
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achieve target-specific action and avoid unwanted uptake by healthy cells without any
major toxic effects. Further, nanotechnology enhanced the target specificity along
with controlled and sustained drug release, which is one of the major advancements
over conventional drug treatment.
3 Therapeutic Barrier and Targeting
Nanomaterials have to cross various barriers to reach their target, like intestinal
barrier and blood–brain barrier. To solve this problem, nanocarriers must be soluble
or colloidal in aqueous solution and be made of biocompatible material that can
be easily functionalized. It should have a long half-life and shelf life with a low
rate of aggregation and shows high intake in cancer cells compared with healthy
cells. The treatment is effective only when the proper dose is provided and shows
maximum activity in the tumor cells. Thus it can become inefficient since the effect
of anticancer drugs is mitigated by increasing time for the drug to reach the target.
The nanomaterials should be capable of delivering the drugs in and around the cancer
cells and increase its local concentration, thus reducing toxicity toward normal cells.
Thereby an effective target selection prior to disease treatment is always the top
precedence in nanotechnology that can be achieved successfully via both active and
passive targeting.
3.1 Active and Passive Targeting
Active targeting mainly indicates the direct action at targeted location that are well
programmed to bind to specific receptor molecules such as proteins, carbohydrates,
lipids expressed on the diseased cells, or molecules present in its microenvironment
or the physicochemical environment surrounding the targeted disease or malfunctioning system. This approach also known as active targeting or ligand-mediated
targeting that involves affinity-based recognition, facilitated intake, and retention in
the cells. Taking into account the complexity of routes for nanoparticle administration and its interactions with various cells in the body, the differences in the affinity
toward the cancerous and normal cells cannot be the basis for efficient and successful
drug delivery to the target cells by the nanoparticles. Thus, a single nanocarrier is
conjugated with multiple ligands for targeting multiple receptors. However, for using
active targeted anticancer platforms, multiple factors including ligand density on the
nanoparticle surface and affinity between the carrier and the target need to be optimized. Sometimes non-internalization of the nanocarrier is desired for bystander
effect, due to which solid tumors lacking the specific receptors can be killed by the
release of drug at the surface of neighboring cells that can bind with carriers. Contrary
to the belief that a higher number of ligands will facilitate stronger binding, it has
been observed that ligand density does not increase the affinity toward the target
495
achieve target-specific action and avoid unwanted uptake by healthy cells without any
major toxic effects. Further, nanotechnology enhanced the target specificity along
with controlled and sustained drug release, which is one of the major advancements
over conventional drug treatment.
3 Therapeutic Barrier and Targeting
Nanomaterials have to cross various barriers to reach their target, like intestinal
barrier and blood–brain barrier. To solve this problem, nanocarriers must be soluble
or colloidal in aqueous solution and be made of biocompatible material that can
be easily functionalized. It should have a long half-life and shelf life with a low
rate of aggregation and shows high intake in cancer cells compared with healthy
cells. The treatment is effective only when the proper dose is provided and shows
maximum activity in the tumor cells. Thus it can become inefficient since the effect
of anticancer drugs is mitigated by increasing time for the drug to reach the target.
The nanomaterials should be capable of delivering the drugs in and around the cancer
cells and increase its local concentration, thus reducing toxicity toward normal cells.
Thereby an effective target selection prior to disease treatment is always the top
precedence in nanotechnology that can be achieved successfully via both active and
passive targeting.
3.1 Active and Passive Targeting
Active targeting mainly indicates the direct action at targeted location that are well
programmed to bind to specific receptor molecules such as proteins, carbohydrates,
lipids expressed on the diseased cells, or molecules present in its microenvironment
or the physicochemical environment surrounding the targeted disease or malfunctioning system. This approach also known as active targeting or ligand-mediated
targeting that involves affinity-based recognition, facilitated intake, and retention in
the cells. Taking into account the complexity of routes for nanoparticle administration and its interactions with various cells in the body, the differences in the affinity
toward the cancerous and normal cells cannot be the basis for efficient and successful
drug delivery to the target cells by the nanoparticles. Thus, a single nanocarrier is
conjugated with multiple ligands for targeting multiple receptors. However, for using
active targeted anticancer platforms, multiple factors including ligand density on the
nanoparticle surface and affinity between the carrier and the target need to be optimized. Sometimes non-internalization of the nanocarrier is desired for bystander
effect, due to which solid tumors lacking the specific receptors can be killed by the
release of drug at the surface of neighboring cells that can bind with carriers. Contrary
to the belief that a higher number of ligands will facilitate stronger binding, it has
been observed that ligand density does not increase the affinity toward the target