Magnetic nanoparticles (MNPs) are magnetically different particles because they are very small, ranging in size from 1 nm to 100 nm. These nanoparticles are composed of magnetic elements, like iron oxide, cobalt or nickel, and they behave very differently from the bulk element in terms of both size and surface chemistry. Magnetic nanoparticles have these properties even at their tiny size, which distinguishes them from larger materials, which might exhibit them only under certain conditions, and can be used for all sorts of purposes, from biomedical research to environmental protection to materials science.
Magnetic nanoparticles usually have a core of magnetism like Fe3O4 (magnetite) or Fe2O3 (hematite), with a shield of biocompatible material like silica or polymers. It is a structure that not only gives the nanoparticles their magnetic quality, but makes them stable, functional and biocompatible for all kinds of applications.
The nicest thing about magnetic nanoparticles is that you can play with them by an external magnetic field. That's how they can be manipulated to move, target and separate in ways that benefit drug delivery, cancer treatment and pollution removal.
Magnetic nanoparticles are very different from other types of particles, which makes them particularly desirable for applications. These features are very strongly affected by the size, shape and surface of the nanoparticles.
Superparamagnetism: Superparamagnetim is one of the biggest advantages of magnetic nanoparticles. But while larger magnetic particles are still magnetized once the field is removed, superparamagnetic nanoparticles become magnetized only with an external magnetic field, and de-magnetized when the field is removed. It is important for biomedical purposes like drug delivery and MRI, because it guarantees that the nanoparticles will not lump together and are easy to manipulate in a biological system.
Surface Area and Reactivity: Because magnetic nanoparticles are tiny, their surface area is very large compared to their volume. This large surface area makes them highly reactive and can be functionalized with any chemical group, such as peptides, antibodies, or drugs, which can be used for selective drugs and diagnostics.
Magnetic Capability: Magnetic nanoparticles can be moved, placed and stacked in precise ways using magnetic fields from outside the system. This characteristic comes in handy for targeting drugs and chemotherapy for cancer as the nanoparticles can be directed at a specific location in the body.
Biocompatibility: Most magnetic nanoparticles, especially iron oxide nanoparticles, are biocompatible which is to say that they don't lead to a great deal of toxicity or immune activation upon absorption into the body. This property is essential for biomedical uses like delivery of drugs, imaging and treatment of cancer.
Variable Properties: Magnetic nanoparticles can be tailored in size, shape and surface chemistry for different applications. These parameters are set during synthesis so that scientists can optimize the nanoparticles for specific applications such as their stability, dispersibility or targeting potential.
Magnetic nanoparticles can be categorized based on their composition, magnetic behavior, and structure. The main types include:
Ferromagnetic Nanoparticles: These nanoparticles exhibit strong and permanent magnetization. They retain their magnetic properties even in the absence of an external magnetic field. Common ferromagnetic nanoparticles include cobalt and nickel nanoparticles.
Ferrimagnetic Nanoparticles: These nanoparticles have opposing magnetic moments that do not cancel each other out. As a result, they exhibit weaker magnetization than ferromagnetic nanoparticles but still retain some magnetization. Examples include magnetite (Fe3O4) and maghemite (Fe2O3).
Superparamagnetic Nanoparticles: Superparamagnetic nanoparticles do not retain their magnetization once the external magnetic field is removed. Their magnetization only occurs when exposed to a magnetic field. Iron oxide nanoparticles, such as magnetite (Fe3O4), are examples of superparamagnetic nanoparticles.
Core-Shell Magnetic Nanoparticles: These nanoparticles consist of a magnetic core, often made of iron oxide, surrounded by a non-magnetic shell, which can be made from biocompatible materials such as silica or polymers. The shell provides stability and prevents aggregation while allowing for functionalization of the nanoparticles.
Magnetic Nanocomposites: Magnetic nanocomposites combine magnetic nanoparticles with other materials to enhance their properties or introduce new functionalities. For example, magnetic silica nanoparticles can be used for drug delivery or environmental cleanup, combining the advantages of both materials.
The synthesis of magnetic nanoparticles is a crucial step in determining their properties, including size, shape, surface characteristics, and magnetic behavior. Several methods are used to synthesize magnetic nanoparticles, each offering different advantages depending on the desired application.
Co-Precipitation Method: One of the most widely used methods for synthesizing iron oxide nanoparticles is co-precipitation. In this method, iron salts, such as iron (III) chloride (FeCl3) and iron (II) chloride (FeCl2), are mixed with a precipitating agent, such as sodium hydroxide (NaOH), in an aqueous solution. The nanoparticles are formed by the reaction of these precursors, and the particle size can be controlled by adjusting factors such as temperature, pH, and concentration.
Sol-Gel Method: The sol-gel process involves the transition of a precursor solution into a gel, which is then heat-treated to form nanoparticles. This method allows for precise control over the size and composition of the nanoparticles and is often used to synthesize magnetic nanocomposites, such as magnetic silica nanoparticles.
Hydrothermal Synthesis: Hydrothermal synthesis involves the reaction of metal salts in an aqueous solution under high temperature and pressure. This method is useful for producing high-quality magnetic nanoparticles with controlled size and shape, as well as for creating magnetic nanocomposites.
Microemulsion Method: Microemulsion synthesis involves the creation of small droplets of a water-in-oil or oil-in-water emulsion, which serve as nanoreactors for the formation of magnetic nanoparticles. This method allows for precise control over the size and distribution of the nanoparticles.
Laser Ablation Method: In this method, a laser is used to vaporize a target material, such as metal or metal oxide, in a liquid or gas environment. The vapor condenses into nanoparticles, which can be collected and characterized for various applications.
Fig.1 Common methods for preparing magnetic nanoparticles. (Mittal, Ashi, et al., 2022)
Magnetic nanoparticles are typically composed of materials that exhibit ferromagnetic, ferrimagnetic, or superparamagnetic behavior. Some of the most common types of magnetic nanoparticles include:
Iron Oxide Nanoparticles (Fe3O4 and Fe2O3): Iron oxide nanoparticles, such as magnetite (Fe3O4) and maghemite (Fe2O3), are the most widely studied magnetic nanoparticles due to their biocompatibility, ease of synthesis, and unique magnetic properties. These nanoparticles are commonly used in drug delivery, magnetic resonance imaging (MRI), and hyperthermia treatment for cancer.
Cobalt Nanoparticles (Co): Cobalt nanoparticles exhibit strong ferromagnetic properties and are used in a range of applications, including magnetic data storage, sensors, and catalysis. They are less commonly used in biomedical applications due to potential toxicity concerns but remain important in industrial processes.
Nickel Nanoparticles (Ni): Nickel nanoparticles, like cobalt, possess strong magnetic properties and have applications in data storage, catalysis, and as magnetic sensors. However, their use in biomedical applications is limited due to concerns about their toxicity and biocompatibility.
Magnetic Nanocomposites: These nanoparticles combine magnetic materials with other substances, such as polymers, metals, or silica, to enhance the magnetic properties or introduce new functionalities. Magnetic nanocomposites are used in a variety of applications, including targeted drug delivery and environmental monitoring.
Manganese Ferrite Nanoparticles (MnFe2O4): These nanoparticles possess high stability and are used in various applications, including MRI and environmental cleanup.
Magnetic nanoparticles have a wide range of applications due to their unique magnetic properties, biocompatibility, and versatility. Some of the most promising applications include cancer therapy, drug delivery, and water purification.
Magnetic Nanoparticles for Cancer Therapy
Magnetic nanoparticles have shown significant potential in cancer therapy due to their ability to be directed to specific tumor sites and used for various therapeutic techniques, including hyperthermia and targeted drug delivery. Hyperthermia is a treatment in which magnetic nanoparticles are exposed to an alternating magnetic field, causing them to generate heat and induce localized heating in the tumor. This heat can kill cancer cells or make them more susceptible to other treatments, such as chemotherapy or radiation therapy.
Magnetic nanoparticles can also be used to deliver anticancer drugs directly to the tumor site, minimizing damage to surrounding healthy tissue. By functionalizing the nanoparticles with targeting ligands, such as antibodies or peptides, researchers can ensure that the nanoparticles selectively bind to cancer cells, improving the efficacy of the treatment.
Magnetic Nanoparticles for Drug Delivery
Magnetic nanoparticles are widely used in drug delivery due to their ability to carry therapeutic agents and be guided to specific locations within the body using an external magnetic field. This targeted drug delivery method helps minimize systemic toxicity and side effects, making the treatment more effective. The surface of magnetic nanoparticles can be functionalized with various drug molecules, peptides, or other targeting agents, allowing for precise control over drug release and targeting.
For example, iron oxide nanoparticles are commonly used to deliver chemotherapy drugs directly to tumor cells, reducing the need for high doses of drugs that may affect healthy tissues. Magnetic nanoparticles can also be used to deliver genes or vaccines, making them a promising tool for gene therapy and immunotherapy.
Fig.2 Application of magnetic nanoparticles in drug and nucleic acid delivery. (Jacob, Ayden, and Krishnan Chakravarthy., 2014)
Magnetic Nanoparticles for Water Purification
Magnetic nanoparticles are increasingly being used for environmental applications, such as water purification. Due to their high surface area and magnetic properties, magnetic nanoparticles can be used to remove contaminants from water, including heavy metals, dyes, and organic pollutants. The magnetic particles can adsorb contaminants, and then an external magnetic field can be used to separate the nanoparticles from the water, along with the pollutants.
Magnetic nanoparticles can also be functionalized with specific groups to target particular pollutants, such as arsenic or lead, making them highly effective for water treatment. This method is particularly attractive because it is cost-effective, reusable, and environmentally friendly.
BOC Sciences offers a wide range of magnetic nanoparticle products as well as customized products in different types and sizes to meet a variety of research and application needs. Below is the list of products we can provide, if you have more needs, please contact us to customize the synthesis of your magnetic nanoparticles.
| Product Type | Available Sizes | Price |
| Fe3O4 Nanoparticle | 20-70 nm, 100nm | Inquiry |
| Fe2O3 Nanoparticle | 20-70 nm, 100nm | Inquiry |
| OA Coated Zn1-xFe2O4 Nanoparticles | 20-70 nm, 100nm | Inquiry |
| MnxZn1-xFe2O4 Nanoparticles | 20-70 nm, 100nm | Inquiry |
| Product Type | Price |
| Core Shell Magnetic Nanoparticles | Inquiry |
| Fluorescent Magnetic Nanoparticles | Inquiry |
| Gold Coated Magnetic Nanoparticles | Inquiry |
| Graphene Oxide Magnetic Nanoparticles | Inquiry |
| Magnetic Gold Nanoparticles | Inquiry |
| Magnetic Iron Oxide Nanoparticles | Inquiry |
Magnetic nanoparticles are used in drug delivery, magnetic resonance imaging (MRI), hyperthermia therapy, and water treatment due to their magnetic responsiveness.
Magnetic nanoparticles are made via co-precipitation of iron salts in alkaline media, thermal decomposition, or hydrothermal synthesis, producing materials like magnetite (Fe3O4).
Magnetic nanoparticles were first explored for drug delivery in the 1970s, focusing on magnetic guidance to target drugs precisely to diseased sites.
Nanoparticles have magnetic properties due to unpaired electron spins in their atoms, producing a net magnetic moment. Iron oxides, like Fe3O4, exhibit superparamagnetism at the nanoscale.
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