Chemists develop compounds capable of forming heath-resistant, economic and biocompatible gels

 Eating a yogurt or a jelly, using a pharmaceutical or cosmetic cream or shampoo... are just some of the numerous everyday actions in which we use gels developed through a process of gelation. Researchers from Universitat Jaume I have patented a new family of compounds that enables to develop gels more resistant to high temperatures with a higher level of biocompatibility and able to work with a variety of organic solvents, and all this with an easy synthesis, scalable and low cost.

This family of compounds has significant applications in industries such as pharmaceuticals and cosmetics or food industry, among others.

A jellifying agent is a substance that when is added to a liquid, transforms it into ice. When the liquid used is water, it is called hydrogel. But if the solvents used are organic compounds, they use organojellifying compounds such as the developed by the group Sustainable chemistry: supported reactants and catalysts. Supramolecular chemistry from the UJI, led by the chair professor Santiago Luis. 'Normally, when we develop a compound or family compounds able to form organogels, they only act in such a way in a very small number of solvents. The fundamental difference is that our group of compounds is capable of forming gels with a very high range of solvents', the researcher explains.

Another contribution of the compound is its ability to maintain stability at temperatures up to 100° C, thus allowing the products to keep their properties. In addition, the basic chemical structures that form compounds are amino acids, which provide products that are in most cases biocompatible. 'As they have units easily acceptable by the biological world, they don't have incompatibility, allergies or toxicities problems," Santiago Luis stresses.

To all these advantages, we have to add the fact that these compounds with a jellifying action at low concentrations are cheap.

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The above story is reprinted from materials provided by Universitat Jaume I.

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Breakthrough in molecular motors: First molecular piston capable of self-assembly

Researchers from CNRS and the Université de Bordeaux, in collaboration with a Chinese team (1), have developed the first molecular piston capable of self-assembly. Their research represents a significant technological advance in the design of molecular motors. Such pistons could, for example, be used to manufacture artificial muscles or create polymers with controllable stiffness.

The results are published on 4 March 2011 in the journal Science.

Living organisms make extensive use of molecular motors in fulfilling some of their vital functions, such as storing energy, enabling cell transport or even moving about in the case of bacteria. Since the molecular layouts of such motors are extremely complex, scientists seek to create their own, simpler versions. The motor developed by the international team headed by Ivan Huc (2), CNRS researcher in the "Chimie et Biologie des Membranes et des Nanoobjets" Unit (CNRS/Université de Bordeaux), is a "molecular piston." Like a real piston, it comprises a rod on which a moving part slides, except that the rod and the moving part are only several nanometers long.

More specifically, the rod is formed of a slender molecule, whereas the moving part is a helix-shaped molecule (both are derivatives of organic compounds especially synthesized for the purpose). How can the helicoidal molecule move along the rod? The acidity of the medium in which the molecular motor is immersed controls the progress of the helix along the rod: by increasing the acidity, the helix is drawn towards one end of the rod, as it then has an affinity for that portion of the slender molecule. By reducing the acidity, the process is reversed and the helix goes in the other direction.

This device has a crucial advantage compared to existing molecular pistons: self-assembly. In previous versions, which take the form of a ring sliding along a rod, the moving part is mechanically passed onto the rod with extreme difficulty. Conversely, the new piston is self-constructing: the researchers designed the helicoidal molecule specifically so that it winds itself spontaneously around the rod, while retaining enough flexibility for its lateral movements.

By allowing the large scale manufacturing of such molecular pistons, this self-assembly capacity augurs well for the rapid development of applications in various disciplines: biophysics, electronics, chemistry, etc. By grafting several pistons together end-to-end, it could be possible, for example, to produce a simplified version of an artificial muscle, capable of contracting on demand. A surface bristling with molecular pistons could, as and when required, become an electrical conductor or insulator. Finally, a large-scale version of the rod on which several helices could slide would provide a polymer of adjustable mechanical stiffness. This goes to show that the possibilities for this new molecular piston are (almost) infinite.

(1) From the Beijing National Laboratory for Molecular Sciences

(2) His team is part of the Institut Européen de Chimie et Biologie.

Story Source:

The above story is reprinted (with editorial adaptations) from materials provided by CNRS (Délégation Paris Michel-Ange).

Journal Reference:

Quan Gan, Yann Ferrand, Chunyan Bao, Brice Kauffmann, Axelle Grélard, Hua Jiang, Ivan Huc. Helix-Rod Host-Guest Complexes with Shuttling Rates Much Faster than Disassembly. Science, 4 March 2011; Vol. 331 no. 6021 pp. 1172-1175 DOI: 10.1126/science.1200143