Nanoparticles – Fields of Usage
Nanoparticles are particles in the nanosized range (10-9m) that can be made from various materials; this poster will focus specifically on iron oxide nanoparticles (IONs). Due to their small size and unique optical, photochemical, magnetic, and chemical properties, IONs are being used as a new approach in cancer therapy as an alternative to conventional treatments. Iron oxide nanoparticles are overcoming limitations, such as unintended side effects and resistance to treatment, of current cancer treatment options (Pankhurst, 2003).
IONs are being researched for several potential benefits in cancer therapy. Two of these ways include tumor targeting and induced apoptosis via magnetism. Tumor targeting involves coating the nanoparticles in ligands recognized by the tumor cells (Pankhurst, 2003). After this coating is applied, the nanoparticles can be used as treatment in different ways. One way involves bonding the nanoparticle with a chemotherapeutic drug, injecting the nanoparticle-drug combination into the patient, and directing the nanoparticle-drug combination to the tumor site via an external magnet (Domenech et al., 2013).
The second way is performed by injecting only the coated nanoparticle into the patient, guiding it to the tumor site via an external magnet, and finally inducing apoptosis within the cell by means of a dynamic magnetic field (DMF). These mechanisms of combating cancer will reduce damage to healthy cells and improve the efficiency of existing chemotherapy drugs (Zhang et al., 2014).
Iron oxide nanoparticle consists of two parts, hydrophilic shell and hydrophobic core. The hydrophilic shell contains target ligands which make IONs bind to specific targets such as tumor cells. The hydrophobic core carry therapeutic drugs (Jin et al., 2014). n magnetic targeting, nanoparticles are coated with a ligand that binds to specific receptors found on tumor cells. An external magnetic field, usually established by a strong permanent magnet such as Nd-Fe-B, near the tumor is applied to attract the nanoparticles with a magnetic force given by the equation below (Pankhurst, 2003). Fm = Vm ??? (1/2 B?H) Fm= magnetic force Vm= volume of the particle ???= effective susceptibility of the particle relative to water B= flux density/magnetic flux H= strength of magnetic field Magnetic targeting of nanoparticles can be used either to aid chemotherapeutic agents to the tumor or as the first step in induced apoptosis via magnetism.
When aiding chemotherapeutic agents, the nanoparticle, after having been coated with a ligand targeted for the tumor, is then mixed with the chemotherapeutic agent and injected into the bloodstream. An external magnetic field is applied near the area of the location of the tumor. The nanoparticles are directed to the tumor via the magnet and bind to the tumor via the coating of ligand. In this way, the chemotherapeutic agent is delivered directly to the tumor, increasing the efficiency and decreasing the toxicity of the drug (Pankhurst, 2003).
A magnet is placed outside the body in order that its magnetic field gradient might capture magnetic carriers flowing in the circulatory system (Pankhurst, 2003). As described in the first section, iron oxide nanoparticles are directed to tumor cells via magnetic targeting. The iron oxide nanoparticles can then be influenced by a dynamic external magnetic field (DMF) to mechanically rupture lysosomes and thus induce apoptosis within targeted cancer cells (Zhang et al., 2014). Rotational movement of the iron oxide nanoparticles about their axes is induced by a device called a DMF generator. A dynamic force field is created by the generator.
Inside the nanoparticles, this field is transformed into a magnetic flux field, B, which works on the IONs with magnetic momentum, ?, and moment of inertia, I. This field creates a torque: ?= I ? A ?= ? ?B ?=magnetic momentum I=inertia A=area ?=torque ?= magnetic flux field The oscillatory torques generated from the DMF create shearing forces that destroy the lysosome membrane, resulting in the emptying of the lysosomes innards into the surrounding cytoplasm (Zhang et al., 2014). The acidic content of the lysosome triggers the formation of free radicals within the cell. These free radicals damage the cell’s DNA which signals the cell for apoptosis. Since the nanoparticles are targeted to the cancer cells, only the lysosomes of the cancer cells burst, therefore, only cancer cells undergo apoptosis making this a safe and effective way to treat cancer (Domenech et al., 2013).
When iron oxide nanoparticles (IONs) enter lysosomes and bind to the membrane, DMF generator will be activated and IONs start to rotate. The force will cause the disruption of the lysosomal membrane and then induce the rapid cell mediated necrobiosis (Zhang et al., 2014). The basic concepts regarding the interactions between IONs and a DMF were reviewed. The applied mechanisms of IONs pertaining to contemporary medicinal practices were tested as well. The focus was in particular on cell-drug delivery and rapid cell induced necrobiosis mediation. However, these methodologies are only two of the many medicinal uses of magnetic nanoparticles that are currently being tested. The main mechanism was oscillatory movement of magnetic IONs; a magnetic twisting cytometry, a process in which magnetic IONs are bound to specific receptors on a cell wall.
Using the DMF generator, IONs within the cell can have controlled rotational movement. This rotational nanoparticle movement can be utilized for distal induction of apoptosis by damaging lysosomal membrane structures. Treating patients with lysosome-targeted IONs proves to be a noninvasive mechanism allowing for remote apoptosis (Zhang et al., 2014). The expansion of cancer therapies with different modes of action is crucial in targeting cancer cells which evade chemotherapeutic treatment.
Chemotherapy drugs become more effective than non-specific therapies with the novel approach of inducing cell mediated apoptosis via ligand-receptor tumor recognition. This shows the greatest advantage of the cancer therapy in selectively killing cancer cells (Pankhurst, 2003). This technique induced apoptosis which killed the cell without creating any damaged to its surrounding tissue and accelerated the healing process. The lack of significant heat produced by this procedure allowed researchers to study the mechanisms of nanoparticle rotation. Nanoparticles are an emerging technology that are being explored for numerous uses beyond the scope of this poster.