title: Combination of acoustic levitation with small angle scattering techniques and synchrotron radiation circular dichroism. Application to the study of protein solutions.
abstract: The acoustic levitation technique is a useful sample handling method for small solid and liquids samples, suspended in air by means of an ultrasonic field. This method was previously used at synchrotron sources for studying pharmaceutical liquids and protein solutions using x-ray diffraction and small angle x-ray scattering (SAXS).
  
  
  
  In this work we combined for the first time this containerless method with small angle neutron scattering (SANS) and synchrotron radiation circular dichroism (SRCD) to study the structural behavior of proteins in solutions during the water evaporation. SANS results are also compared with SAXS experiments.
  
  
  
  The aggregation behavior of 45μl droplets of lysozyme protein diluted in water was followed during the continuous increase of the sample concentration by evaporating the solvent. The evaporation kinetics was followed at different drying stage by SANS and SAXS with a good data quality. In a prospective work using SRCD, we also studied the evolution of the secondary structure of the myoglobin protein in water solution in the same evaporation conditions.
  
  
  
  Acoustic levitation was applied for the first time with SANS and the high performances of the used neutron instruments made it possible to monitor fast container-less reactions in situ. A preliminary work using SRCD shows the potentiality of its combination with acoustic levitation for studying the evolution of the protein structure with time.
  
  
  
  This multi-techniques approach could give novel insights into crystallization and self-assembly phenomena of biological compound with promising potential applications in pharmaceutical, food and cosmetics industry. This article is part of a Special Issue entitled "Science for Life" Guest Editor: Dr. Austen Angell, Dr. Salvatore Magazù and Dr. Federica Migliardo.
authors.affiliation: Institut Laue Langevin, 71 avenue des Martyrs, 38000 Grenoble cedex 2, France.
authors.forename: Viviana
authors.initials: V
authors.lastname: Cristiglio
authors.affiliation: Institut Laue Langevin, 71 avenue des Martyrs, 38000 Grenoble cedex 2, France.
authors.forename: Isabelle
authors.initials: I
authors.lastname: Grillo
authors.affiliation: Department of Physics and Chemistry, University of Palermo, via Archirafi 36, 90123 Palermo, Italy.
authors.forename: Margarita
authors.initials: M
authors.lastname: Fomina
authors.affiliation: Synchrotron Soleil, L'Orme des Merisiers, BP 48, 91192 Gif sur Yvette Cedex, France.
authors.forename: Frank
authors.initials: F
authors.lastname: Wien
authors.affiliation: Allergan Inc., 2525 Dupont Drive, Irvine, CA 92612, USA.
authors.forename: Evgenyi
authors.initials: E
authors.lastname: Shalaev
authors.affiliation: CNRS-CEMHTI, University of Orléans, 1D avenue de la Recherche Scientifique, 45071, Orléans cedex 2, France.
authors.forename: Alexey
authors.initials: A
authors.lastname: Novikov
authors.affiliation: CNRS-CEMHTI, University of Orléans, 1D avenue de la Recherche Scientifique, 45071, Orléans cedex 2, France.
authors.forename: Séverine
authors.initials: S
authors.lastname: Brassamin
authors.affiliation: Synchrotron Soleil, L'Orme des Merisiers, BP 48, 91192 Gif sur Yvette Cedex, France.
authors.forename: Matthieu
authors.initials: M
authors.lastname: Réfrégiers
authors.affiliation: Synchrotron Soleil, L'Orme des Merisiers, BP 48, 91192 Gif sur Yvette Cedex, France.
authors.forename: Javier
authors.initials: J
authors.lastname: Pérez
authors.affiliation: CNRS-CEMHTI, University of Orléans, 1D avenue de la Recherche Scientifique, 45071, Orléans cedex 2, France. Electronic address: louis.hennet@cnrs-orleans.fr.
authors.forename: Louis
authors.initials: L
authors.lastname: Hennet
mesh_terms: D000162:Acoustics; D000818:Animals; D002645:Chickens; D002942:Circular Dichroism; D006736:Horses; D009113:Muramidase / Q000032:analysis; D009211:Myoglobin / Q000032:analysis; D033363:Neutron Diffraction; D011506:Proteins / Q000032:analysis*; D053838:Scattering, Small Angle; D012996:Solutions; D013057:Spectrum Analysis; D017356:Synchrotrons; D014867:Water / Q000737:chemistry
chemical_list: D009211:Myoglobin; D011506:Proteins; D012996:Solutions; D014867:Water; D009113:Muramidase
keywords: Acoustic levitation; Aggregation; Circular dichroism spectroscopy; Lysozyme; Myoglobin; Small angle scattering