title: Effect of dense gas CO2 on the coacervation of elastin.
abstract: In this study for the first time the effect of high-pressure CO2 on the coacervation of alpha-elastin was investigated using analytical techniques including light spectroscopy and attenuated total reflection Fourier transform infrared (ATR-FTIR) spectroscopic imaging and circular dichroism (CD) spectroscopy. The coacervation behavior of alpha-elastin, a protein biopolymer, was determined at temperatures below 40 degrees C and pressures lower than 180 bar. At these conditions elevated pressures did not disrupt the ability of alpha-elastin to coacervate. It was feasible to monitor the presence of amide I, II, and III bands for alpha-elastin at high-pressure CO2 using ATR-FTIR imaging. At a constant temperature the peak absorption was substantially enhanced by increasing the pressure of the system. CD analysis demonstrated the preservation of secondary structure attributes of alpha-elastin exposed to dense gas CO2 at the pressure range investigated in this study. The lower critical solution temperature of alpha-elastin was dramatically decreased from 37 to 16 degrees C when the CO2 pressure increased from 1 to 50 bar, without a significant change after that. Carbon dioxide at high pressures also impeded the reversible coacervation of alpha-elastin solution. These effects were predominantly associated with the lowered pH of the aqueous solution and maybe the interaction between CO2 and hydrophobic domains of alpha-elastin.
authors: School of Chemical and Biomolecular Engineering, University of Sydney, Sydney, New South Wales 2006, Australia. F.Dehghani@usyd.edu.au
authors: Fariba
authors: F
authors: Dehghani
authors: Nasim
authors: N
authors: Annabi
authors: Peter
authors: P
authors: Valtchev
authors: Suzanne M
authors: SM
authors: Mithieux
authors: Anthony S
authors: AS
authors: Weiss
authors: Sergei G
authors: SG
authors: Kazarian
authors: Feng H
authors: FH
authors: Tay
mesh_terms: D000577:Amides / Q000737:chemistry; D000818:Animals; D002245:Carbon Dioxide / Q000494:pharmacology*; D002417:Cattle; D002942:Circular Dichroism / Q000379:methods; D004549:Elastin / Q000378:metabolism*; D011312:Pressure; D012965:Sodium Chloride / Q000737:chemistry; D013055:Spectrophotometry, Infrared / Q000379:methods; D017550:Spectroscopy, Fourier Transform Infrared / Q000379:methods; D013696:Temperature
chemical_list: D000577:Amides; D002245:Carbon Dioxide; D012965:Sodium Chloride; D004549:Elastin