**2. The nanosystem unit components**

## **2.1 Nanospheres and nanorods**

Matrices, which have a particle size of 10–100 nm and which are prepared with natural or synthetic polymers and where the active substance is trapped in the particle, are called nanospheres. **Figure 2** shows the structure of the nanospheres. Polymeric nanoparticles are divided into nanocapsules and nanospheres.

**Figure 1.** *Structure of nanosystems.*

monodispersed short gold nanorods. The El-Sayed method of nanorod concentration determination is currently the standard way of measuring extinction coefficients (*ε*), and involves the coupling of bulk gold concentration, transmission

Emulsification polymerization is applied as a polymerization technique, and monomers are polymerized into nanospheres. Polymethylmethacrylate and poly cyanoacrylate polymers are among the most commonly used polymers for

emulsification in the polymerization process. After polymerization, the active substance dissolves in the medium and is bonded with nanospheres or attached to the surface. The obtained material is purified, freeze-dried and the nanospheres are

This method is based on the electrostatic interaction of the two aqueous phases and the nanospheres are prepared from natural polymers. Polyelectrolytes form hydrogel beads by cross-linking with counterions. These hydrogel beads are also called gelispheres. Gelispheres spreads into the polymer structure and forms a cross-linked cage. In this way, biomolecules can be trapped in this lattice structure. Examples of synthetic monomers and polymers used in this method include hydroxyethyl methacrylate, N-vinyl-2-pyrrolidone, N-isopropylacrylamide, vinyl acetate, acrylic acid, polyethylene glycol acrylate/methacrylate, polyethylene glycol diacrylate/dimethacrylate. Chitosan, gelatin, alginate fibrin, collagen, hyaluronic acid, dextran can be used as a natural polymer. Multivalent cations are generally

electron microscopy (TEM) size analysis and absorbance data.

*The Components of Functional Nanosystems and Nanostructures*

*DOI: http://dx.doi.org/10.5772/intechopen.92027*

*2.1.1 Polymerization*

*The methods of obtaining nanospheres.*

**Figure 3.**

synthesized [7].

*2.1.2 Ionic gelation*

**115**

**Figure 2.** *The structure of nanospheres [1].*

The nanospheres may be crystalline and amorphous. It is very advantageous because of its imprisonment, injection and dispersion properties [1].

Nanospheres have many advantages in their application areas. Nanospheres, especially in the field of medicine, can find a wide range of applications because they can easily pass through capillaries, penetrate tissue cavities easily, target organs, be formulated in a controlled manner, and reduce toxicity effects. Furthermore, due to the minimum particle size, they tend to agglomerate and form pellets and are challenging to obtain in liquid and solid forms. Nanospheres are obtained by polymerization, solvent displacement, salting out, controlled gelification, ionic gelation, solvent evaporation, and desolvation techniques [2–4] (**Figure 3**).

The nanorods are nanoscale materials that have unique optical properties like nanospheres. They are also expected to play an important role as both interconnects and functional units in fabricating electronic, optoelectronic, electrochemical and electromechanical nanodevices. Nanoscale materials such as fullerenes, nanorods, quantum dots and metallic nanoparticles have unique properties, because of their high surface area to volume ratio. Nanorods are used in many application fields such as dye solar cell, oligonucleotide detection, applied electric field and humidity sensitive. It should be recommended to synthesize nanorods in bulk in particular for biomedical fields. Nanorods are examined by extinction and scattering spectroscopy, DLS, TEM methods [5, 6]. Synthesis of gold nanorods has recently undergone dramatic improvements. It is possible to produce high yields of nearly

*The Components of Functional Nanosystems and Nanostructures DOI: http://dx.doi.org/10.5772/intechopen.92027*

#### **Figure 3.** *The methods of obtaining nanospheres.*

monodispersed short gold nanorods. The El-Sayed method of nanorod concentration determination is currently the standard way of measuring extinction coefficients (*ε*), and involves the coupling of bulk gold concentration, transmission electron microscopy (TEM) size analysis and absorbance data.
