Seite - 77 - in Cancer Nanotheranostics - What Have We Learnd So Far?

Conniotet al. Nanocarriers for immunecell targetingand tracking FIGURE3 | (A)Liposomesarephospholipidandcholesterol self-assembled bilayermembranes thatencloseanaqueouscore,wherehydrophilic moleculescanbe incorporated.Hydrophobiccompoundscanalsobe incorporated in the lipidbilayer. Liposomescanbeclassified in (i) small unilamellar vesicles (SUVs); (ii) largeunilamellar vesicles (LUVs) and (iii) multilamellar vesicles (MLVs), according to their sizeand lamellarity. (B)Polymericnanoparticlesaresubmicronspherical entitiescomposedbya polymeric compactnet thancaneither constituteapolymericmatrix—in the caseofnanospheres—orapolymericwall surroundingavesicular core—nanocapsules.Nanoparticlescan transporthydrophilic andhydrophobic moleculeseitherentrapped in thepolymericmatrixor core,or adsorbed to their surface. (C)Polymericmicellesareself-assembledspherical nanocarriers formedbyamphiphilicblockcopolymers. Inaqueousmedium, theblockcopolymersarrange themselves inadispositionwhere themost hydrophobicpartsof their chains formahydrophobiccore—where hydrophobicmoleculescanbe incorporated–, and themosthydrophilic regionsof thepolymerchainaredisplayedoutoward. (D)Dendrimersare hyperbranchednanocarriers formedbyacentral core,branchingmonomers and functionalizedperipheral groups.Dendrimersynthesiscanstart fromthe coreelement (divergentpolymerization)or fromtheperipheral branching units (convergentpolymerization), resulting inastructurewithahydrophilic surfaceandahydrophobiccentral core.Moleculescanbe transportedby dendrimerseither incorporated in thecoreandbranches,eitherconjugated to the terminal groups. apolymerwall that surroundsacorecontaining thecargo(Singh andLillard,2009). Several methods have been used to produce polymeric nanoparticles.Someof themost studiedarespray-drying, salting out, nanoprecipitation and emulsion-basedmethods, The latter, in particular, lies on an emulsification processwith the removal of organic solvents used for polymer dissolution, by extrac- tion or evaporation. The emulsified organic drops containing Frontiers inChemistry | ChemicalEngineering November2014 |Volume2 |Article105 | 77