Equilibrium cluster formation in concentrated protein solutions and colloids

Controlling interparticle interactions, aggregation and cluster formation is of central importance in a number of areas, ranging from cluster formation in various disease processes to protein crystallography and the production of photonic crystals. Recent developments in the description of the interaction of colloidal particles with short-range attractive potentials have led to interesting findings including metastable liquid–liquid phase separation and the formation of dynamically arrested states (such as the existence of attractive and repulsive glasses, and transient gels). The emerging glass paradigm has been successfully applied to complex soft-matter systems, such as colloid–polymer systems and concentrated protein solutions. However, intriguing problems like the frequent occurrence of cluster phases remain. Here we report small-angle scattering and confocal microscopy investigations of two model systems: protein solutions and colloid–polymer mixtures. We demonstrate that in both systems, a combination of short-range attraction and long-range repulsion results in the formation of small equilibrium clusters. We discuss the relevance of this finding for nucleation processes during protein crystallization, protein or DNA self-assembly and the previously observed formation of cluster and gel phases in colloidal suspensions.

[1]  Broide,et al.  Using phase transitions to investigate the effect of salts on protein interactions. , 1996, Physical review. E, Statistical physics, plasmas, fluids, and related interdisciplinary topics.

[2]  Jan Groenewold,et al.  Anomalously large equilibrium clusters of colloids , 2001 .

[3]  Wilson C. K. Poon,et al.  TOPICAL REVIEW: The physics of a model colloid-polymer mixture , 2002 .

[4]  Schofield,et al.  Three-dimensional direct imaging of structural relaxation near the colloidal glass transition , 2000, Science.

[5]  D. Langevin,et al.  Surfactant-Induced Collapse of Polymer Chains and Monodisperse Growth of Aggregates near the Precipitation Boundary in Carboxymethylcellulose−DTAB Aqueous Solutions , 2003 .

[6]  Re-entrant glass transition in a colloid-polymer mixture with depletion attractions. , 2002, Physical review letters.

[7]  M Fuchs,et al.  Multiple Glassy States in a Simple Model System , 2002, Science.

[8]  C. Tanford,et al.  Interpretation of protein titration curves. Application to lysozyme. , 1972, Biochemistry.

[9]  J. S. Pedersen,et al.  The aggregation behavior of zinc-free insulin studied by small-angle neutron scattering , 2004, European Biophysics Journal.

[10]  P. Schurtenberger,et al.  Reappearance of structure in colloidal suspensions , 2002 .

[11]  V. Prasad,et al.  Glasslike kinetic arrest at the colloidal-gelation transition. , 2001, Physical review letters.

[12]  C. Zukoski,et al.  Ergodic and non-ergodic phase transitions in globular protein suspensions. , 2003, Faraday discussions.

[13]  Stefano Mossa,et al.  Equilibrium cluster phases and low-density arrested disordered states: the role of short-range attraction and long-range repulsion. , 2004, Physical review letters.

[14]  M. Malfois,et al.  A model of attractive interactions to account for fluid–fluid phase separation of protein solutions , 1996 .

[15]  Phase equilibria and glass transition in colloidal systems with short-ranged attractive interactions: application to protein crystallization. , 2001, Physical review. E, Statistical, nonlinear, and soft matter physics.

[16]  Benedek,et al.  Observation of critical phenomena in a protein-water solution. , 1989, Physical review letters.

[17]  A. Blaaderen,et al.  A colloidal model system with an interaction tunable from hard sphere to soft and dipolar , 2003, Nature.

[18]  L. Cipelletti,et al.  Jamming phase diagram for attractive particles , 2001, Nature.

[19]  F. Sciortino.  One liquid, two glasses , 2002, Nature materials.

[20]  K. Dawson.  The glass paradigm for colloidal glasses, gels, and other arrested states driven by attractive interactions , 2002 .

[21]  Franz Rosenberger,et al.  Liquid-Liquid Phase Separation in Supersaturated Lysozyme Solutions and Associated Precipitate Formation/Crystallization , 1997 .

[22]  Roberto Piazza,et al.  Interactions and phase transitions in protein solutions , 2000 .

[23]  W. Poon,et al.  Gelation in model colloid-polymer mixtures , 2003 .