Adsorption of Biopolymer at Solid−Liquid Interfaces. 1. Affinities of DNA to Hydrophobic and Hydrophilic Solid Surfaces

Abstract

The extent of adsorption (Γ2 1) of DNA from aqueous solution on different hydrophobic and hydrophilic solid surfaces has been compared as a function of pH, temperature, ionic strength of the medium, and denaturants. Γ2 1 at a given surface (except sephadex) increases with an increase of the nucleotide concentration (X 2) of DNA in mole fraction units, but it attains a monolayer saturation value Γ2 m when X 2 attains a value X 2 m . In most cases Γ2 1 increases further when X 2 ≫ X 2 m . Various neutral electrolytes like LiCl, KCl, CsCl, KBr, CaCl2, and Na2SO4, surfactants like SDS and Triton-X 100, the denaturing action of heat, and the addition of acid and alkali have been observed to play an important role during the study of the adsorption of DNA on charcoal powder. Further, a comparative study has been performed to examine the relative affinity of DNA toward different types of solid surfaces. The significant role of different types of surfaces in controlling the adsorption process has been explained in terms of Gibbs' surface excess quantities. The experimental results have been interpreted in terms of maximum work due to the free energy change of DNA adsorption on various solid surfaces and more quantitatively in terms of the standard free energy change (ΔG°) for the saturation of the surface by DNA as a result of the change in the nucleotide concentration in the bulk from zero to unity in mole fraction units.

Excess adsorption of biomolecules on soft surfaces: Adsorption of DNA, proteins and lactose on fatty surfaces

“…Earlier from adsorption interaction DNA from solution are found to occur onto various types of surfaces of insoluble protein and cellulose [9,13,14]. But in the present work, we are able to show that DNA may also undergo adsorption interaction on the surface of insoluble organic lipids such free fatty acids, triglyceride fats, phosphatidyl choline and cholesterol.…”

“…Subsequently, extensive studies of relative adsorption of different soluble proteins in pure and mixed forms on different types of rigid surfaces of powdered substance of known specific surface areas have been studied by various workers [3][4][5][6][7][8]. In a series of papers Chattoraj and coworkers studied extensively the adsorption of deoxyribonucleic acid (DNA), ribonucleic acid (RNA) and nucleo-histone on the rigid surfaces of alumina, silica, charcoal, resins and chromium metal surfaces using analytical and micro-electrophoretic techniques [9][10][11][12][13][14][15]. Following thermodynamic approaches of Bull [1,2], these workers evaluated affinities or standard free energy changes of adsorption using integrated forms of the Gibbs adsorption equations.…”

Effect of biochar on nitrous oxide emission and its potential mechanisms

“…Several important analytical challenges arise as a result of the strong sorption of lysed cells, cell contents, and microbial exoenzymes to biochar. When biochar is added to soil, DNA yield typically decreases (Jin, 2010), and this phenomenon has been described previously for various charcoals and activated carbons (Gani et al, 1999). Enzyme interactions with biochars have been studied by Bailey et al who recommended fluorescence studies because sorption can make color reactions less reliable (Bailey et al, 2010).…”

Silica Surface Features and Their Role in the Adsorption of Biomolecules: Computational Modeling and Experiments

“…The same question was formulated by several authors. 690,[696][697][698][699] Summarizing the results of these different works, one may conclude that the energetic contributions to DNA interaction with a silica surface can be categorized into three parts: i) the electrostatic effect (repulsive); ii) the dehydration effect; iii) DNA/silica Hbonding. As regards point i), it was observed that an increase of the salt concentration (namely, the ionic strength) led to an increase of adsorption, which was more pronounced for divalent than for monovalent cations.…”