Thermosensitive lanthanide complexes of hyaluronan.
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.
Vercruysse
Koen P
KP
Department of Medicinal Chemistry, The University of Utah, 419 Wakara Way, Suite 205, Salt Lake City, Utah 84108, USA.
Li
Hao
H
Luo
Yi
Y
Prestwich
Glenn D
GD
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
D003102:Colloids; D028581:Lanthanoid Series Elements; D012996:Solutions; D006820:Hyaluronic Acid