Molecular Origin for Strong Agarose Gels: Multi-Stranded Hydrogen Bonding

Abstract

Agarose gels are currently used in separation, purification, and characterization of DNA, RNA, proteins, and polysaccharides in gel electrophoresis, gel filtration, affinity chromatography, and ion chromatography techniques. Specifically, it is used in PCR (Polymerase Chain Reaction) test. Although, double stranded intermolecular hydrogen bonding between OH-2 and 3,6-ring oxygen atoms of 1,4-linked anhydro-α-L-galactopyranose residues on different molecules take place, triple- or multi-stranded secondary association occur with increasing concentration. The multi-stranded gelation mechanism of agarose molecules is the first to report. The associated agarose molecules play a dominant role in the centre of tetrahedral cavities that are occupied by ice-like hydrogen bonded water molecules which are caused thermodynamically by cage and hydrophobic effects. Many investigations the gelling properties of the polysaccharides have been undertaken to elucidate the structure-function relationship, but no other researchers have established the mechanisms at the molecular level including water molecules. There are structural and theoretical consistencies in our investigation. This paper provides important information not only academia, but also to industrial fields, such as bio-physicochemical analysis, food, cosmetics, agriculture, pharmaceuticals, drug delivery, drug storage, tissue engineering, and biotechnology.