Surface ligands in synthesis, modification, assembly and biomedical applications of nanoparticles

Abstract

Nanotechnology hasreceivedextraordinaryattentionrecentlyduetoitsburgeon- ing roleinbiomedicalscience.Thematerialscomposingthenanoparticlesproducefascinating and diversefunctionalitiesasaresultoftheirexceptionallysmallsize.Infact,evenseemingly insignificant changesinparticlesizecanhaveprofoundeffectsontheseproperties.Thussize control, bothduringsynthesisandinparticlesuspensions,isa sine quanon for functionality. This canbeaccomplishedbymaskingtheparticlesurfacewithamultitudeofdifferentlig- ands. Notonlycansurfaceligandsconstrainthegrowthofnucleation,theycanalsodirectthe shape ofcrystallization.Howevernosingleligandcandoeverything.Fortunatelyligandsare essentially fungibleandcanbeexchangedatvarioustimestoconferthedesiredproperties to theparticle.Thiscanincludeprotectingtheparticlefromharshaqueousconditions,such as pHextremes,maximizingopticalpropertiesfordiagnosticsorshieldingtheparticlefrom potentially hostileconditionsfoundinthebody.Becausethesemoietiesinteractubiquitously with variousbiologicalmaterials,particularlyproteins,thereneedstobearationalizeddesign of surfaceligands.Thedesignoftheligandcanhavecrucialeffectsonbiodistributionaswell as evasionofbiologicaldefenses.Ligandscanevenbedesignedtoprovidenewfunctionality in responsetovariousenvironmentalstimulitoimprovetheirtherapeuticordiagnosticcapa- bilities. Consideringtheimportanceofligandsthenonthisemergingfield,thisreviewwill thoroughly considertheliganddesignforthevariousstepsofnanodevelopment,fromsynthesis and assemblythroughbiomedicaltranslation. © 2014ElsevierLtd.Allrightsreserved.