title: In situ spectroscopic quantification of protein-ice interactions.
abstract: FTIR and confocal Raman microspectroscopy were used to measure interactions between albumin and ice in situ during quasi-equilibrium freezing in dimethyl sulfoxide (DMSO) solutions. At temperatures of -4 and -6 °C, albumin was found to be preferentially excluded from the ice phase during near-equilibrium freezing. This behavior reversed at lower temperatures. Instead, DMSO was preferentially excluded from the ice phase, resulting in an albumin concentration in the freeze-concentrated liquid phase that was lower than predicted. It is hypothesized that this was caused by the albumin in the freeze-concentrated liquid getting adsorbed onto the ice surface or becoming entrapped in the ice phase. It was observed that, under certain freezing protocols, as much as 20% of the albumin in solutions with starting concentrations of 32-53 mg/mL may be adsorbed onto the ice interface or entrapped in the ice phase.
authors.affiliation: Biostabilization Laboratory, Mechanical Engineering Department, College of Science and Engineering, University of Minnesota, Minneapolis, Minnesota 55455, USA.
authors.forename: Alan
authors.initials: A
authors.lastname: Twomey
authors.forename: Rebekah
authors.initials: R
authors.lastname: Less
authors.forename: Kosaku
authors.initials: K
authors.lastname: Kurata
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Takamatsu
authors.forename: Alptekin
authors.initials: A
authors.lastname: Aksan
mesh_terms: D000818:Animals; D002417:Cattle; D003460:Crystallization; D004121:Dimethyl Sulfoxide / Q000737:chemistry; D005615:Freezing; D007053:Ice / Q000032:analysis*; D012710:Serum Albumin, Bovine / Q000737:chemistry*
chemical_list: D007053:Ice; D012710:Serum Albumin, Bovine; D004121:Dimethyl Sulfoxide