Globally, cancer is the second most prevalent healthcare issue, following cardiovascular. Conventional methods such as chemotherapy and radiotherapy have several detrimental side effects without guaranteeing permanent recovery. In the last few decades, efforts have been made by introduce nanotechnology to cancer therapeutics. Owing to the size range of the nanomaterials, i.e., 1 nm to 500 nm (1 nanometre is one billionth of a meter), their remarkable physiological properties, provided scope for diagnosis at an early stage and therapeutics at a cellular level. Recently, nanoengineering of the structural aspects of nanomaterials has significantly improved their properties and given them functional advantages over their bulk counterparts. Polymeric nanocomposites are one such example, where a polymer matrix constitutes homogenously dispersed nanofillers or nanoparticles to obtain better physiochemical properties. Physiological properties play a great role in the interaction and functioning of polymeric nanocomposites on biological surfaces. The ratios of polymer matrix and nanomaterials could easily be modulated to control the surface charge and surface chemistry of the polymeric nanocomposites. Consequently, providing smart properties such as self-healing, intelligent sensing, shape memory and self-cleaning to different polymeric nanocomposites. Additionally, the use of natural or derived polymers for the synthesis of polymeric nanocomposites makes them less toxic and biocompatible. Therefore, they provide an opportunity for innovative healthcare and biomedicine applications in areas of stimulus-response, such as cancer therapeutics.
Conventional anticancer drugs have several limitations, like a short half-life, low absorption and specificity, a low therapeutic index, a large volume of distribution, insufficient bioavailability, instability in blood circulation and cytotoxicity. Smart polymeric nanocomposites are believed to possess one or more physical or chemical properties that could easily be controlled using internal stimuli (such as pH, solvent, chemical, biochemical, etc.) or external stimuli (such as temperature, magnetic field, light, ultrasound, etc.). Therefore, scientific research on the advancement and development of smart polymeric nanocomposite is rapidly growing for cancer therapeutics due to (1) efficient drug encapsulation; (2) easy interaction between drug and antibody, peptides, aptamers, etc.; (3) controlled (specific amount) and sustained (over a specific period) drug release at the targeted sites; (4) very low inflammatory response and immunogenicity; (5) biodegradable and economic. The nanocarriers designed using these smart polymeric nanocomposites are targeted to the tumour site to overcome the above-mentioned limitations of anticancer drugs. The major advantage of these nanocarriers is sustained release in blood circulation, which reduces the frequent uptake of the drug. Therefore, it is promising feature to maintain the release profile of anticancer therapeutic drugs through some intracellular stimuli such as blood sugar, pH, oxygen levels, ionic strength, internal temperature, and enzymes.
The polymeric nanocomposites are generally prepared using solution mixing, melt intercalation, in-situ polymerisation, template synthesis, etc. However, the preparation of efficient polymeric nanocomposite required the selection of an appropriate synthesis method depending on the physical and chemical properties of the polymer. Natural and derived polymers such as chitosan, cellulose, alginate, collagen, etc. are frequently used for the synthesis of these composites. Natural polymers offer some unique mechanical properties. However, it often comes with the limitation of time-consuming extraction and purification processes. On the other hand, nanomaterials are can be synthesized in different shapes and sizes that could provide very large interfacial areas post-dispersion into a polymer matrix. However, the limitation of nanomaterial aggregation prevents their efficient dispersion into polymer matrices. To obtain high-performance polymeric nanocomposites, good dispersion of nanomaterials is a must. Therefore, a specific combination of polymer and nanomaterials is used during synthesis to obtain good dispersion. Moreover, a high aspect ratio of nanomaterials is most important for loading drugs into the polymeric nanocomposites. For biological applications, primarily metal or metal oxide nanomaterials (such as gold, silver, copper, iron oxide, zinc oxide nanoparticles, etc.) and carbon-based nanomaterials (carbon nanotubes, graphene, graphene-oxide, and carbon dots) are combined with anticancer drug-coupled or impregnated suitable polymeric matrix to form polymeric nanocomposite drug carriers. drug delivery system can be targeted via two processes:
Active targeting: is based on receptor-ligand interaction, where a specific ligand-tagged polymeric nanocomposite drug carrier is targeted towards tumorous cells having respective receptors. Therefore, it destroys only tumorous cells without affecting healthy cells. Hence, increases the selectivity of the cell, which ultimately reduces the chance of cytotoxicity and side effects associated with an unwanted distribution of drugs within the entire body.
Passive targeting: is based on the enhanced permeability and retention (EPR) effect. Drug-loaded polymeric nanocomposites of certain sizes (200 nm) can permeate only through leaky vasculature, such as tumour tissues. Therefore, it is more effective on tumour tissues without accumulating much towards normal tissues. These drugs are targeted to the affected site by the body’s natural immune system, which enhances its circulation for a longer time and protects clearance either by the reticuloendothelial system or opsonisation. This functionality is achieved by using hydrophilic polymers such as polyethylene glycol during the synthesis of polymeric nanocomposites.
Read more: https://www.pharmafocusasia.com/articles/smart-polymeric-nanocomposites-for-cancer-therapeutics
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