Adsorption of proteins and nucleic acids on clay minerals and their interactions: A review

The understanding of adsorption of proteins and nucleic acids on clay minerals and their interactions is important in biological applications for soil ecosystem, the earth's biochemical evolution and origin of life, delivery of drug, etc. This review summarizes adsorption of proteins and nucleic acids (DNA, RNA) on natural clay minerals of layer phyllosilicates such as montmorillonite, kaolinite and illite and their interactions. Recent advances in adsorption mechanisms, adsorption sites and effect of various factors on adsorption are discussed. The interaction mechanisms are suggested to be cation exchange, electrostatic interactions, hydrophobic/hydrophilic interactions, ligand exchange, cation bridge, water bridge, hydrogen bond and van der Waals forces. The physical and chemical characteristics of clay minerals and proteins and nucleic acids are mainly responsible for the absorption of these biomolecules by clay minerals besides external conditions, for instance pH and ion strength of absorption solution. Finally, comments on the perspectives and potential benefits of the studies on adsorption of proteins and nucleic acids on clay minerals and their interactions are also made. (C) 2013 Elsevier B.V. All rights reserved.