Selective Adsorption of Biopolymers on Zeolites

Abstract

Zeolites adsorb biopolymers on their surface and may be suitable as a new type of chromatographic carrier material for proteins, nucleic acids, and their conjugates. We report here various parameters that influence the adsorption of biopolymers on synthesized zeolites with regard to the Si/Al2 ratio and three-dimensional structure. There are three physicochemical principles that may underly the adsorption: 1) below the isoelectric point (pI), mainly Coulombic attraction similar to ion-exchange chromatography; 2) at pI, hydrophobic interactions (a kind of van der Waals attraction) plus the three-dimensional mesopore structure; and 3) above pI, the sum of the Coulombic repulsion and attraction forces, such as the hydrophobic interaction, and also substitution reaction of water on the Al molecule with a protein amino-base. At high Si/Al2 ratio in the presence of a small amount of Al and with mesopores between the zeolite particles, maximal adsorption was seen at pI and was suggested to be dependent on the number of hydrophobic interaction points on the mesopores, and their morphology. The application of zeolites to biochemistry and biotechnology is also discussed.

Lead removal by polyacrylamide-bentonite and zeolite composites: Effect of phytic acid immobilization

“…From the comparison of Fig. 1b and c with d, it can be postulated that the inclusion of Phy to the composite is as hydrogen bond formations between P-OH of Phy and Si-OH and Al-OH of Z for which the declines at 2500 cm −1 for Si-OH and 800 cm −1 of Al-OH and the absence of the broad band around 2350-2400 cm −1 of P-OH were evidences [26][27][28][29]. Fig.…”

“…Langmuir Freundlich ratio provides a higher degree of hydrophobicity [27]. The ratio for Z was 4/1 so that its swelling was low.…”

Enzymes immobilized in mesoporous silica: A physical–chemical perspective

“…Which interactions that are dominant are also depending on immobilization conditions. For instance, hydrophobic interactions might dominate if the immobilization is performed close to the pI of the protein but play only a minor role if both the protein and the solid surface are strongly charged [134].…”

A method for the molecular imprinting of hemoglobin on silica surfaces using silanes

“…Furthermore, using organic silanemonomers, multiple functional groups can be easily introduced into the polysiloxane network during polymerization, for example, amino functional groups, aldehyde functional groups and alkyl chains, forming hydrophobic interactions. It has been suggested by Matsui et al [16] that such hydrophobic interactions are essential for selective protein adsorption on silicon materials.…”