Nanoparticles are important nano-materials and the size of nanoparticles ranges from 1 nm to 1000 nm. Compared with bulk materials, nanoparticles have the characteristics of small size, which makes the nanoparticles have nano-effect. Moreover, nanoparticles have unique performances in optical, thermal, mechanical and magnetism properties. With those advantages, nanoparticles have important academic value and broad prospects in the fields of photoelectric, chemistry and life science.
- Biomedicine field: Nanoparticles have been widely used in biomedicine field. When the nanoparticles contain groups or compounds that have environmental stimulus responsiveness, the nanoparticles can be used as stimulus response sensors. In addition, nanoparticles can be combined with biological molecules such as DNA, enzymes, organelle and the others in the body to produce specific responses and achieve biological specific markers. Moreover, the size of nanoparticles is generally much smaller than that of biological cells, so nanoparticles can be used as carriers of drugs / genes in living organisms.
Figure 1. An example of nanoparticles applied in biomedicine field.
- Catalytic field: With the advantages of unique crystal structure and surface characteristics, nanoparticles are widely used in catalytic field, and the activity and selectivity are much higher than those of traditional catalysts. As a new catalyst material, nanoparticle has attracted the attention of the catalytic workers and has been called the fourth - generation catalyst internationally.
Figure 2. An example of nanoparticles applied in catalytic field.
- The others: Nanoparticles also can be used in other fields. Nanoparticles can be used as magnetic materials such as permanent magnet materials, magnetic recording materials and magnetic fluid materials. In addition, they can be applied in the field of analysis and others.
From the perspective of composition and structure, nanoparticles can be divided into organic nanoparticles, inorganic nanoparticles and organic / inorganic hybrid nanoparticles.
- Organic nanoparticles: Organic nanoparticles can be divided into carbon nanoparticles, polymer nanoparticles and organic composite nanoparticles. The simplest composition of organic nanoparticles is carbon nanoparticles containing only carbon elements, which can be divided into crystalline carbon nanoparticles and amorphous carbon nanoparticles according to their degree of crystallization. Polymer nanoparticles are usually composed of crosslinked polymers with good storage stability and biocompatibility. Moreover, organic composite nanoparticles combine the advantages of carbon nanoparticles and polymer nanoparticles, which can be divided into multipolymer nanoparticles and carbon / polymer composite nanoparticles.
- Inorganic nanoparticles: According to the compositions, inorganic nanoparticles can be divided into pure metal nanoparticles and inorganic composite nanoparticles. Silver, gold, nickel, palladium and other noble metal nanoparticles are common among pure metal nanoparticles, which has the advantages of excellent conductivity, large specific surface area and good biocompatibility. Compared with pure metal nanoparticles, inorganic composite nanoparticles are more complex in composition, such as quantum dots, up-conversion nanoparticles, magnetic nanoparticles, and the others.
- Organic / inorganic hybrid nanoparticles: Organic / inorganic hybrid nanoparticles are compatible with inorganic and organic components at the nanoscale. The organic components can be supporting carriers of composite nanoparticles, solving the physical and chemical instability of nanomaterials, while inorganic components give hybrid particles superior properties of diversification.
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