Core Shell Nanoparticles

Core Shell Nanoparticles List

Core-shell nanoparticles are nanocomposites with the special atomic arrangement of "shell and core", which can be regarded as the tailoring and modification of the original nanoparticles, usually denoted as "core @ shell". For example, the gold nanoparticle material coated by a layer of polymer PMMA is recorded as Au@ PMMA. The properties of this kind of composite nanoparticles are not a simple superposition of the original properties of "1 + 1", but can be made to have new functional properties by adding a specific "shell". It is a kind of "particle surface engineering". Through the interactive adjustment of the electronic structure between the nuclear atom and the shell atom, the new particle properties can be qualitatively changed, showing unique properties of light, electricity, catalysis and so on. Nanomaterials with core-shell structure such as metal @ metal, metal @ inorganic, inorganic @ inorganic, metal @ polymer, metal @ semiconductor and so on are hot spots of research.

Figure 1. Applications of Core-shell nanoparticles in various areas of modern technology.

Applications:

• Biomedicine: Core-shell nanoparticles have been applied in many aspects of the biomedical field, and have a lot of potential application value. In the field of biomedicine, core-shell nanoparticles are mainly used to control drug transport, biological imaging, cell labeling, biosensors and regenerative medicine. For example, nanoparticles with biocompatible Si as shell and magnetic or superparamagnetic elements as core have good biocompatibility and are used to control drug transport in living cells. In biological applications, nanoparticles can also be used to detect damaged cells, DNA, RNA, cholesterol and so on. Nanoparticles with magnetic materials as the core and fluorescent materials, silicon dioxide, metals or polymers as shells have this detection function. For example, Si-coated ZnS/Mn nanoparticles can be used to detect Cu2⁺ ions, and Au/Ag core-shell nanoparticles can be used to detect tumor cells in vivo.

Figure 2. Superparamagnetic iron oxide inclusions encapsulate microbubbles for drug delivery.

• Catalytic: Magnetic nanoparticles coated with functional shells such as precious metals and semiconductors often have better physical properties (optical, catalytic activity, electrical, magnetic and thermal properties) than unit metal nanoparticles. For example, nano-oxide materials such as MgO and CaO have strong adsorption capacity for halogenated hydrocarbons and organic phosphides, and if the surface is coated with a transition metal oxide layer such as Fe₂O₃, the adsorption capacity can be increased several times. A similar example is that coating Fe₂O₃ on the surface of Au nanoparticles can significantly improve the catalytic ability of Au to convert CO to CO₂. Nanomaterials with core-shell structure are also used in the field of photocatalysis. Studies have shown that depositing TiO₂ nanostructures on the surface of some metal nanoparticles can increase the electron transition rate under the excitation of ultraviolet light.
• Magnetochemistry: The giant magnetoresistance effect (GMR) refers to a phenomenon in which the resistivity of magnetic materials varies greatly with or without the effect of an external magnetic field. Giant magnetoresistance is a quantum mechanical effect, which arises from the layered magnetic film structure. This structure is composed of alternate thin layers of ferromagnetic material and non-ferromagnetic material. Core-shell structured magnetic nanomaterials have been found to have broad application prospects in giant magnetoresistance induction technology. Its magnetoresistance can vary with temperature, particle size, core size and small layer thickness. This makes core-shell structured nanomaterials useful There is huge room for GMR technology.

References

1. Manoj B. Gawande. Radek Zboril. (2015) "Core–shell nanoparticles: synthesis and applications in catalysis and
   Electrocatalysis" Chem. Soc. Rev. 44, 7540-7590
2. Krishnendu Chatterjee. SreerupaSarkarK. (2014) "Core/shell nanoparticles in biomedical applications." Advances in Colloid and Interface Science. 209: 8-39