title: Thermosensitive lanthanide complexes of hyaluronan.
abstract: Addition of trivalent lanthanide salts to solutions of hyaluronan (HA), a naturally occurring anionic polysaccharide, resulted in an unexpected reverse-temperature phase transition (RTPT); i.e., the complexes were soluble when cooled but precipitated when warmed. A unique lower critical solution transition temperature (LCST) was observed for each lanthanide in the order (increasing LCST) Eu(3+) < Nd(3+)< Ce(3+) < Gd(3+) < La(3+) < Tb(3+) < Dy(3+) < Yb(3+) < Lu(3+) for high molecular weight HA. Moreover, the LCST values increased as the molecular weight of the HA decreased from 1730 to 190 kDa. The precipitation-dissolution behavior was fully reversible in a cyclical fashion; a lag in redissolution was observed as the temperature was lowered, and longer incubation times at each temperature minimized this lag. The RTPT behavior could be ablated by titration with 8 kDa HA to produce complexes soluble at ambient temperature. This is the first description of RTPT behavior in a biologically important glycosaminoglycan.
authors.affiliation: Department of Medicinal Chemistry, The University of Utah, 419 Wakara Way, Suite 205, Salt Lake City, Utah 84108, USA.
authors.forename: Koen P
authors.initials: KP
authors.lastname: Vercruysse
authors.forename: Hao
authors.initials: H
authors.lastname: Li
authors.forename: Yi
authors.initials: Y
authors.lastname: Luo
authors.forename: Glenn D
authors.initials: GD
authors.lastname: Prestwich
mesh_terms: D011232:Chemical Precipitation; D003102:Colloids / Q000737:chemistry; D006820:Hyaluronic Acid / Q000737:chemistry*; D028581:Lanthanoid Series Elements / Q000737:chemistry*; D008970:Molecular Weight; D012996:Solutions; D013057:Spectrum Analysis; D013696:Temperature
chemical_list: D003102:Colloids; D028581:Lanthanoid Series Elements; D012996:Solutions; D006820:Hyaluronic Acid