Types of nanoliposomes Like the liposomes based on structure nanoliposomes are of following types: 1. Small unilamellar vesicles (SUV’s): They have a single lipid layer around them and are generally 25-50 nm in diameter. Sonication is carried out to form small unilamellar vesicles (SUVs). SUVs are not efficient encapsulates of large functional foods and nutraceutical compounds because of low aqueous core volume to lipid ratio 88. 2. Large unilamellar vesicles (LUV’s): These vesicles having heterogenous group which are surrounded by a solitary lipid layer. They are giant vesicles having size from 100 nm up to cell size. Large unilamellar vesicles (LUVs) are obtained from extrusion 89. They can carry large piles of encapsulated water-soluble compounds in their internal core because of large aqueous core volume to lipid ratio and therefore are more appropriate for hydrophilic compound encapsulation 90-91. 3. Multilamellar vesicles (MLV’s): They have up to 14 lipid layers arrangement like an onion, which are separated by a layer of aqueous solution. These vesicles are 100 nm in diameter. The hydrated lipid sheets get self close to form large multilamellar vesicles (MLVs) 92-93. Formulation of nanoliposomes Nanoliposomes have been prepared by various methods which are described here. 1. Sonication Technique Sonication is a trouble-free technique for plummeting the size of liposomes and for the preparation of nanoliposomes (Figure 1) 94-97. In this method, hydrated lipid vesicles are treated with a probe sonicator in a temperature controlled environment for several minutes. The phospholipid components and cholesterol are mixed in chloroform–methanol by sonication and the mixture is dried by lyophilization or spray drying 98. Then, the dried lipids are hydrated with a fluid containing chelating agents, salts, cryo-protectants, stabilizers, and the drug to be encapsulated. At first, micrometric type liposomes will be formed which are sonicated for a required time period 99. Liu and Park prepared chitosan-coated nanosize liposomes by sonication method and studied the different factors that has been affected the loading efficiency and payload of Vitamin C by using high-pressure liquid chromatography 100. Narsaiah et al., prepared Pediocin-loaded nanoliposomes and hybrid alginate nanoliposome to study the effect of various process parameters on nanoliposomes size like quantity of phospholipids, amplitude for sonication and sonication time, and to compare the release profile of pediocin encapsulated in delivery systems prepared from different wall materials 101. Alavi et al., prepared Hydroxyurea nanoliposomes by sonication method to deliver the drug at target site in breast cancer 102. Esfahani et al., prepared Paclitaxel nanoliposomes by sonication method to study the cytotoxic effect of paclitaxel nanoliposomes in breast cancer cell line MCF-7 103. Dadgar et al., prepared Artemisinin loaded nanoliposomes to study their accomplishment on breast cancer cells 104. Shahabi et al., prepared pegylated nanoliposomal hydroxyurea to study the in vitro effect of gold nanoparticles having conjugation with DNA extract obtained from human breast cancer cells, on properties of nanoliposomal hydroxyurea 105. Movahedi et al., prepared nanoliposomes and nanoarchaeosomes of Paclitaxel to study the release pattern by using artificial neural network (ANN) and genetic algorithm (GA) models and to compare the cytotoxic effect of paclitaxel in form of nanoliposomes, pegylated nanoliposomes and nanoarchaeosomes 106. 2. Lipid layer hydration method This method involves drying of lipid to form a thin film by evaporating the organic solvent and then hydrating this film with different aqueous solvents. Lipid layer hydration method can also be used to prepare nanoliposomes (Figure 2) 107-108. A desired amount of lecithin, cholesterol, and butyrated hydroxyl anisole is liquefied in chloroform and mixed vigorously manually. The mixture is then rotated in a vacuum evaporator to evaporate the solvent. Then, the deionized water with drug is used to hydrate the lipid film. The dispersion is sonicated and the preparation is reserved at room temperature for vesicle formation and finally the preparation is stored at low temperature overnight. Mozafari et al., used the thin-film hydration method and the heating method to prepare anionic nanoliposomes 109. Mukherjee et al., developed and compared acyclovir containing nanoliposomes and niosomes to study in vitro whether acyclovir-loaded nanovesicles can help in sustain discharge of the drug by enhancing the residence time and abridged the dose dependent systemic toxicity of acyclovir 110. Meng et al., prepared integrin-targeted and non-targeted paclitaxel nanoliposomes by thin-film hydration method to accomplish the desired solubility and precised targeting of paclitaxel to tumor vasculature 111. Guan et al., prepared lactoferrin nanoliposomes by using thin film hydration method 112, reverse-phase evaporation method 113, and ether injection method 114 to select the best method to build up lactoferrin nanoliposomes and to examine the steadiness of lactoferrin nanoliposomes under different conditions, particularly in the pretend gastrointestinal tract 115. Further, they also compared the three different methods of preparation of the lactoferrin nanoliposomes based on their size distribution and encapsulation efficiency and to estimate the uptake of lactoferrin nanoliposomes by cells and their stability 116. Rasti et al., prepared nanoliposomes by thin-film hydration method and Mozafari method to compare the steadiness of recently prepared and stored liposomal and nanoliposomal systems containing docosahexaenoic acid and eicosapentaenoic acid on the basis of their oxidation 117. Pedrosa et al., prepared nanoliposomes with the help of short chain sphingolipids (SCS) having selective membrane-permeability properties by lipid film hydration and extrusion method using a thermobarrel extruder at 65° to improve nanoliposomal-doxorubicin delivery in tumor cells 118. Markoutsa et al., prepared mono- and dual-decorated nanoliposomes by immobilization of MAb against transferrin and/or a peptide analogue of Apo?3 to target low-density lipoprotein receptor 119-120. da Silva et al., prepared nisin loaded nanoliposomes by lipid layer hydration method to investigate the antimicrobial activity of nanoliposomal nisin containing polyanionic polysaccharides 121.