Phase Behavior of Agarose in Binary Solvents

Ramzi, Mohamed; Rochas, C.; Guenet, Jean‐Michel

doi:10.1021/ma9600062

Cited by 31 publications

(28 citation statements)

References 12 publications

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“…The substitution of the single chain with the double chain model decreases significantly the mobility of agarose, as the rms fluctuation with respect to its backbone drops from 10 Å in the case of the single chain to about 4 Å for the double chain. The double chain agarose structural model here proposed is based on the available literature evidence and in particular on the seminal works of Arnott et al (55), who initially proposed that agarose is formed by bundles of double helixes, left handed, with a helix pitch of 26 Å, and on the successive works of Ramzi et al (56, 57) and, more recently, of Xiong et al (58), who suggested that agarose should be thought of as a random assembly of straight fibers. Clearly, a fiber will be formed by more than a set of two double helixes.…”

Section: Resultsmentioning

confidence: 99%

Molecular Dynamic Investigation of the Interaction of Supported Affinity Ligands with Monoclonal Antibodies

Zamolo

Busini

Moiani

et al. 2008

Biotechnology Progress

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Diagnostics and therapeutic treatments based on monoclonal antibodies have been attaining an increasing importance in the past decades, but their large scale employment requires the optimization of purification processes. To obtain this goal, research is focusing on affinity chromatography techniques and the development of new synthetic ligands. In this work we present a computational investigation aimed at obtaining some guidelines for the rational design of affinity ligands, through the study of their interactions with both monoclonal antibodies (modeled as the FC domain of human IgG) and a model support material (agarose). The study was carried out performing molecular dynamics simulations of the support-spacer-ligand-IgG complex in explicit water. Binding energies between IgG and two supported ligands, a disubstituted derivative of trichlorotriazine and a tetrameric peptide, were determined with the linear interaction energy and MM-GBSA approaches. A detailed study of the possible binding sites of the considered ligands was performed exploiting docking protocols and MD simulations. It was found that both ligands bind IgG in the same site as protein A, which is the hinge region between the CH2 and CH3 domains of IgG. However this site is not easily accessible and requires a high mobility of the ligands. The energetic analysis revealed that van der Waals and electrostatic energies of interaction of the triazine ligand with the support are significant and comparable to those with the protein, so that they limit its capability to reach the protein binding site. A similar result was found also for the tetrameric peptide, which is however able to circumvent the problem; for steric reasons only two of its arms can interact at the same time with the agarose support, thus leaving the remaining two available to bind the protein. These results indicate that the interaction between ligand and support material is an important parameter, which should be considered in the computational and experimental design of ligands for affinity chromatography.

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Section: Resultsmentioning

confidence: 99%

Molecular Dynamic Investigation of the Interaction of Supported Affinity Ligands with Monoclonal Antibodies

Zamolo

Busini

Moiani

et al. 2008

Biotechnology Progress

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“…This mechanism was previously suggested by different authors (Anderson et al , 1969; Arnott et al , 1974), suggesting that the occurrence of double helices during cooling was responsible for the aggregation that produces the 3D hydrogel network, due to hydrogen bonding and hydrophobic interactions. Nevertheless, other studies have suggested that single chain formation would enable gel formation (Foord et al , 1989; Guenet et al , 1993) or the assembly of ternary complexes consisting of agarose–water–co‐solvent would lead to the same structure (Ramzi et al , 1996). The melting of agarose gels can occur at higher temperatures, normally around 85 °C (Normand et al , 2000).…”

Section: Polysaccharides In Cartilage Tissue Engineeringmentioning

confidence: 99%

Polysaccharide-based materials for cartilage tissue engineering applications

Oliveira

Reis

2010

J Tissue Eng Regen Med

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Tissue engineering was proposed approximately 15 years ago as an alternative and innovative way to address tissue regeneration problems. During the development of this field, researchers have proposed a variety of ways of looking into the regeneration and engineering of tissues, using different types of materials coupled with a wide range of cells and bioactive agents. This trilogy is commonly considered the basis of a tissue-engineering strategy, meaning by this the use of a support material, cells and bioactive agents. Different researchers have been adding to these basic approaches other parameters able to improve the functionality of the tissue-engineered construct, such as specific mechanical environments and conditioned gaseous atmospheres, among others. Nowadays, tissue-engineering principles have been applied, with different degrees of success, to almost every tissue lacking efficient regeneration ability and the knowledge and intellectual property produced since then has experienced an immense growth. Materials for regenerating tissues, namely cartilage, have also been continuously increasing and most of the theoretical requirements for a tissue engineering support have been addressed by a single material or a mixture of materials. Due to their intrinsic features, polysaccharides are interesting for cartilage tissue-engineering approaches and as a result their exploitation for this purpose has been increasing. The present paper intends to provide an overview of some of the most relevant polysaccharides used in cartilage tissue-engineering research.

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“…This process should affect markedly the gel mechanical properties such as the magnitude of the elastic modulus which is directly linked to the concentration of the agaroserich phase and to its rigidity. Yet, altering the composition of the binary solvent is seen to have no significant effect on the elastic modulus (Ref 8)…”

mentioning

confidence: 99%

Ternary complexes in agarose gels prepared from binary solvents

Ramzi

Guenet

Rochas

1997

Macromolecular Symposia

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The thermoreversible gelation of agarose has been investigated in four different aqueous binary solvents: Water/dimethyl sulfoxide, water/N,N‐dimethylformamide, water/N‐methylformamide, and water/formamide. The phase diagrams have been subsequently established as a function of agarose concentration and solvent composition. These diagrams suggest the formation of ternary complexes agarose/water/cosolvent.

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Phase Behavior of Agarose in Binary Solvents

Cited by 31 publications

References 12 publications

Molecular Dynamic Investigation of the Interaction of Supported Affinity Ligands with Monoclonal Antibodies

Molecular Dynamic Investigation of the Interaction of Supported Affinity Ligands with Monoclonal Antibodies

Polysaccharide-based materials for cartilage tissue engineering applications

Ternary complexes in agarose gels prepared from binary solvents

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