# Nano-/Microcapsules, Liposomes, and Micelles in
## 2 Spherical Nanoparticles
### Micelles  
#### 2.2.1 Design, Shape, and Size  
Micelles, which are formed through the self-organisation of amphiphilic polymers in aqueous solutions, are nanosized aggregates. Due to their unique properties, they are a suitable matrix for encapsulation, particularly in the context of polysaccharide micelles. Polysaccharides exhibit hydrophilic characteristics, and their hydroxyl, carboxyl, and amino groups can react with hydrophobic compounds to generate amphiphilic polysaccharides [70]. Micelles possess a hydrophobic core and a hydrophilic shell, making them an exceptional carrier for hydrophobic functional food ingredients. The solubility of hydrophobic ingredients increases due to the hydrophilic coating of micelles, while hydrophobic ingredients can be adsorbed or bound by the hydrophobic core of micelles. The hydrophilic coating encapsulates and stabilises the hydrophobic core of the chain (in aqueous solutions). Therefore, amphiphilic di- and tri-block copolymers exceeding 100 nm in size may still be classified as micelles according to [PERSON] et al. [71] and [PERSON] et al. [72]. To form a micelle through self-organisation, hydrophobic molecules attached to the polysaccharide backbone are commonly utilised. Polysaccharides, namely chitosan, dextrin, starch, and maltodextrin [73], are often used in food products. Chitosan-based micelles can be created by adjusting chitosan with hydrophobic groups such as polylactic acid, polycaprolactone, palmitic anhydride, and stearic acid. The chitosan-based polymer that has been modified can naturally produce spherical micelles in aqueous solutions with a size ranging from 20 to 500 nm [73; 74; 75]. To form dextrin-based micelles, the amphiphilic properties of dextrin are modified via techniques such as the Maillard reaction [76; 77] and esterification [78; 79]. Amphiphilic polymers are produced by hydrophobic modification of dextrans to create functional delivery systems for bioactive ingredients. The introduction of maltodextrin and spray drying, when compared to micelles acquired through acid, freeze-drying, or heat treatment, achieved a significantly higher level of stability in curcumin micelles [73]. Starch-based micelles form because of alterations that entail the binding of hydrophobic groups. Such changes attribute amphiphilic properties to the starch. Modification by OSA (octenyl succinin anhydride) esterification is currently the most commonly used method for the hydrophobic modification of starch [54; 73]; in addition, acetic acid anhydride [80] and, in order to synthesise an amphiphilic conjugate (curcumin-hydrophobic component, hydroxyethyl starch-hydrophilic component), an acid-labile ester linker were used [81]. In the literature, we can also encounter polyion complex micelles (also called block ionomer complex micelles) and complex coacervate core micelles. This type of micelle is prepared from oppositely charged polymers under conditions of stoichiometric charge ratios. The presence of a neutral hydrophilic block (usually poly(ethyleneglycol)) attached to one or both components allows electrostatic interactions to be limited to the nanometric dimension of the micelle core, protected from surrounding media by a hydrophilic crown of neutral blocks [82]. To effectively use micelles in a biological setting, it is essential to consider factors such as particle size and shape, critical micelle concentration (CMC), surface potential, and loading efficiency to predict micelle behaviour in a specific environment. The size and percentage of micelle aggregation is dependent on the volume fraction of the hydrophobic block, the degree to which the CMC is exceeded, the mixing speed during micelle synthesis, and the substrate concentration [70]. The dimensions and morphology of micelles can be investigated through DLS (dynamic light scattering), TEM (transmission electron microscopy), and AFM (atomic force microscopy). The self-assembly of amphiphilic molecules leads to an array of nanostructured aggregates exhibiting distinct geometric configurations.