Journal of Student Research 2019

Journal of Student Research 110 which is a consequence of their high surface energy. This aggregation would cause significant problems with the internal body ( in vivo ) applications. In vivo applications include drug delivery, magnetic biodetection, particle imaging, resonance imaging, contrast agents, separation, and therapeutic use. To be appropriately functionalized for in vivo applications, they must be biocompatible and biodegradable because multifunctionality allows nanoparticles to be applied in a variety of situations. They can be applied therapeutically to treat damaged cells, like in the case of cancer. Similarly, MNPs functionalized with targeting antibodies, proteins, and enzymes give them the ability to self-assemble at the damaged site. This ability to self-assemble also increases the effectiveness of NPs to act as fluorescent contrast agents for MRI tests. Soon, MNPs could help end the need for invasive treatments such as radiation and chemotherapy. In vitro applications can work in synergy with in vivo NPs. The first example is nanosensors that detect NPs that bind targeted antibodies to diagnose pathogens. MNPs can also be used for blood purification to remove noxious compounds by binding to them and removing them. Similarly, there are environmental applications for the removal of organic pollutants such as dyes or inorganic pollutants such as metal ions in wastewater. This removal is achieved by MNPs using their specific binding ability to detect or clean biological samples after being changed by biomolecules. Lastly example is tissue engineering uses NPs to repair or reshape damaged tissue using specific nanomaterial scaffolds and growth factors. There are differing main characteristics to consider when developing MNPs for in vivo and in vitro applications. For in vivo applications, the four most important characteristics for MNPs are their biocompatibility, surface functionality, toxicity, and size concerning their diameter and size distribution. Particles sizes in the 10 40 nanometer (nm) range are used in prolonged blood circulation. This particle range has other advantages, like being able to cross capillary walls, and later, are biodegraded naturally by being destroyed by immune cells. [1] Medical applications take advantage of surface modification to accept specific binding of biomolecules MNPs. Currently, only iron oxide nanoparticles (IONPs) are FDA approved in a clinical setting because of their low toxicity, biocompatibility, and biodegradation; making them the ideal MNP to synthesize for medical applications. Reducing MNPs to under 20 nm causes them to become superparamagnetic—meaning they are only magnetic while an external magnet is acting on them—combining these properties with IONPs result in the particle of interest, superparamagnetic iron oxide nanoparticles (SPIONs). SPIONs’ size have their advantages and are shown to be more readily allowed into cells via endocytosis (taking in matter, by folding its membrane to form a vacuole), which is imperative in targeted drug delivery. [4] Another therapy, are placing SPNPs in an alternating current as heating regulators for cancer therapy

111 Toward Magnetic Nanoparticle Synthesis and Characterization for Medical Applications (hyperthermia) [5]. This heat at the site of a tumor can destroy the cancerous cells while causing less damage than to the healthy cells; due to tumor cells being more sensitive to temperature increases. SPIONs at 20 nm satisfy the needed particle range for in vivo use and are better at staying suspended in solution reducing the chance of aggregation which would be disastrous in the body. [2] To prevent this aggregation, NPs are surface modified by creating self-assembled monolayers on the NPs—molecular assemblies that spontaneously form on the surface to create order. [3] Most surface modifications use either a polymer coating or chemical ligand exchange to create this surface order to serve a biological function. Even without modifying and targeting surface ligands, SPIONs’ size positively affects biodistribution. Ten years ago, nanotechnology research was done primarily by PhDs and their research assistants, but every year more universities are adding undergraduate majors in the field. Therein lies a gap in expected knowledge, a gap that this experiment narrowed slightly. Undergraduate researchers and those not familiar with technical details regarding MNPs can miss simple procedural steps when trying to reproduce the experiments from researchers in this field. Undergraduate students could fill this role while gaining traction with the seemingly limitless applications in this field. As you will discover my experiment was partially successful but went awry at the end. Ultimately, this paper is intended to inform undergraduate researchers about lessons learned. which is among eight producible iron-oxides. Extreme sensitivity to oxidizing agents dominates the chemical synthesis of IONPs. Pre-oxidizing magnetite can act as an oxidation barrier—preventing the sudden oxidation of the magnetic nanoparticles to air but can increase particle size. As particle size decreases, the surface area and thereby surface energy increases significantly, increasing the likelihood of particle aggregation. [4] This is where surface modification comes in. Surface modification of SPIONs can be carried out either during synthesis or in a post-synthesis process. The ideal molecules used for stabilization of SPIONs should be biocompatible and biodegradable; hence, the most common molecules used are surfactants such as oleic, lauric, and phosphonic acids. [5] Production of magnetite NPs by co-precipitation is an accessible method. Co-precipitation combines ferric and ferrous ions ( Fe 2+ and Fe 3+ ) in a 1:2 molar ratio in alkaline conditions at 20-90°C. Important variables include temperature, the iron, ion ratio, the pH, the type of salt used (chlorides, sulfates, nitrates), stirring rate, and the rate at which pH is increased, produce differences in the size, shape, and distribution of magnetite NPs. The choice of different precursor anionic salts plays a role in 2. Methods The type of IONPs made in this experiment is magnetite ( Fe3O4 ) NPs,

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