# Nano-/Microcapsules, Liposomes, and Micelles in
## 2 Spherical Nanoparticles
### Nanocapsules
#### 2.1.2 Methods of Obtaining, Factors Affecting Stability, and Properties  
Two methods are employed in the creation of encapsulated systems: top-down and bottom-up. The top-down technique involves reducing the size of large structures by shaping them with external mechanical forces. Techniques used under this approach include the emulsification technique and solvent evaporation. The bottom-up approach involves particle association to develop large particles. Techniques such as spray drying, blanketing, and electrospinning have been used based on this approach [53]. Various techniques can be employed depending on factors such as the core composition, thermolability, coating type, and size parameters required for capsule application. These techniques include pulverisation, coaervation, lyophilisation, molecular inclusion, and the extrusion method, which involves passing bioactive compound-containing polysaccharide solutions through a syringe into a gelling solution. The molecular inclusion technique entails trapping apolar molecules within an apolar cavity through non-covalent bonds, whereas the coaervation process includes the separation of a substance into two phases by adding a third component. Polysaccharide materials can be applied through fluid bed coating, which involves suspending particles in air. Other techniques including vacuum drying, electrospinning, and emulsification are also available. Emulsification requires an emulsifier to stabilise the system [55; 57; 58]. The [PERSON] et al. [59] study effectively utilised the extrusion technique, employing both in situ and two-step encapsulation, to produce capsules composed of alginate and pectin (55:45 ratio) containing a core of papaya fruit extract and gallic acid (a model polyphenol). [PERSON] et al. [60] adopted the coaervation technique in their study, using carboxymethylcellulose and lactoferrin as the wall material to encapsulate \(\beta\)-carotene in sachia inchi oil. The formation of complexes between the biopolymers occurred in two stages. In the first stage, electrostatic interactions dominated, and in the second stage, hydrophobic and hydrogen interactions took over. Currently, the electrospinning technique is a frequently employed method due to its high encapsulation process efficiency, as well as its capacity to maintain compound stability during storage, based on [PERSON] et al. 's techniques [61]. In addition, the electrospinning technique does not entail high-temperature requirements, which is crucial when working with bioactive compounds that are typically thermolabile. The electrospinning process for encapsulation is primarily influenced by the extent of chain entanglement, the chemical composition of the polysaccharide utilised, its molecular weight, and the appropriate concentration required to enable adequate molecular proximity, which allows a chain to bind to the next one [62]. Empirical research has indicated that polysaccharides like starch, recognized by their unique attributes, play a significant role in this process. Polysaccharides, such as alginate, methyl cellulose, pullulan, or dextran, exhibit low shear thinning and are, therefore, not as efficient in encapsulation as those with an anionic group in their structure. This is due to their insufficient entanglement of polymer chains and limited viscosity. As a result, when applying high voltages during electrospinning, such solutions are not able to form continuous streams for fibre formation, as evidenced by [PERSON] et al. [63] and [PERSON] et al. [64].