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1、InternationalJournalofBiologicalMacromolecules21(1997)47±55AlginatebasednewmaterialsKurtIngarDraget*,GudmundSkjaÊk-Brñk,OlavSmidsrùdNorwegianBiopolymerLaboratory(NOBIPOL),DepartmentofBiotechnology,NorwegianUni6ersityofScienceandTechnology,N-7034Trondheim,NorwayReceived19July1996;receivedinrevi
2、sedform18December1996;accepted19February1997AbstractPresentandfutureapplicationsofalginatesaremainlylinkedtothemoststrikingfeatureofthealginatemolecule;i.e.asol:geltransitioninthepresenceofmultivalentcations,e.g.Ca2,almostindependentontemperature.Theseverymildconditions,combinedwiththefacttha
3、talginatesarehighlycharacterisedandunderstoodbothintheliquidandinthegelphase,makesthisbiopolymeruniquecomparedtoothergellingpolysaccharides.Onlypectinsresemblealginateinthesol:geltransitionbehaviour,butthissystemcanhardlybesaidtobeaswellcharacterisedandunderstoodasthealginates.Thepropertiesofa
4、lginatesolutionsandgelssuggestbiomedicalandpharmaceuticaluses.Inthispaper,thequestionofthespeci®cationsrequiredbyapolymerforapplicationsinsomebiomedicalareaswillbediscussed.©1997ElsevierScienceB.V.Keywords:Alginates;Gels;Polysaccharides1.Introduction1b),largeeffectslikecavityformationsbetweenG
5、residuesareobserved.BychemicalfractionationAlginatesmustberegardedasafamilyofco-andnuclearmagneticresonance(NMR)charac-polymerssincethefractionandsequenceoftheterisation[1±4]coupledwithstatisticalmodellingtwomonomers,a-L-guluronicacid(G)andb-D-[5,6],ithasbeenshownthattheoccurrenceofGmannuronic
6、acid(M)(Fig.1a),variesoverawideandMwithinthealginatemoleculeisblock-wiserange.ThefactthatGandMareC5epimers(Fig.1c)andnotrandom.resultsinaswitch-overofthemonomerchairGelationofalginatesisbasedontheaf®nityofconformation,givingrisetoallfourpossiblegly-alginatestowardscertainionsandtheabilitytocos
7、idiclinkagesandatthemolecularlevel(Fig.bindtheseionsselectivelyandcooperatively.Se-lectiveionbindingisstrictlylinkedtothecontent*Correspondingauthor.Tel.:4773598260;fax:47ofguluronateresidues(G),ormoreprecisely,the73591283;e-mail:KDRA
