Heteropolysaccharides in sustainable corrosion inhibition: 4E (Energy, Economy, Ecology, and Effectivity) dimensions

Pectin is structurally and functionally the most complex polysaccharide in plant cell walls. Pectin has functions in plant growth, morphology, development, and plant defense and also serves as a gelling and stabilizing polymer in diverse food and specialty products and has positive effects on human health and multiple biomedical uses. Pectin is a family of galacturonic acid-rich polysaccharides including homogalacturonan, rhamnogalacturonan I, and the substituted galacturonans rhamnogalacturonan II (RG-II) and xylogalacturonan (XGA). Pectin biosynthesis is estimated to require at least 67 transferases including glycosyl-, methyl-, and acetyltransferases. New developments in understanding pectin structure, function, and biosynthesis indicate that these polysaccharides have roles in both primary and secondary cell walls. Manipulation of pectin synthesis is expected to impact diverse plant agronomical properties including plant biomass characteristics important for biofuel production.

Hyaluronic acid (HA), an immunoneutral polysaccharide that is ubiquitous in the human body, is crucial for many cellular and tissue functions and has been in clinical use for over thirty years. When chemically modified, HA can be transformed into many physical forms-viscoelastic solutions, soft or stiff hydrogels, electrospun fibers, non-woven meshes, macroporous and fibrillar sponges, flexible sheets, and nanoparticulate fluids-for use in a range of preclinical and clinical settings. Many of these forms are derived from the chemical crosslinking of pendant reactive groups by addition/condensation chemistry or by radical polymerization. Clinical products for cell therapy and regenerative medicine require crosslinking chemistry that is compatible with the encapsulation of cells and injection into tissues. Moreover, an injectable clinical biomaterial must meet marketing, regulatory, and financial constraints to provide affordable products that can be approved, deployed to the clinic, and used by physicians. Many HA-derived hydrogels meet these criteria, and can deliver cells and therapeutic agents for tissue repair and regeneration. This progress report covers both basic concepts and recent advances in the development of HA-based hydrogels for biomedical applications. Copyright © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Intensive exploration and research in the past few decades on polysaccharide nanocrystals, the highly crystalline nanoscale materials derived from natural resources, mainly focused originally on their use as a reinforcing nanophase in nanocomposites. However, these investigations have led to the emergence of more diverse potential applications exploiting the functionality of these nanomaterials. Based on the construction strategies of functional nanomaterials, this article critically and comprehensively reviews the emerging polysaccharide nanocrystal-based functional nanomaterials with special applications, such as biomedical materials, biomimetic optical nanomaterials, bio-inspired mechanically adaptive nanomaterials, permselective nanostructured membranes, template for synthesizing inorganic nanoparticles, polymer electrolytes, emulsion nano-stabilizer and decontamination of organic pollutants. We focus on the preparation, unique properties and performances of the different polysaccharide nanocrystal materials. At the same time, the advantages, physicochemical properties and chemical modifications of polysaccharide nanocrystals are also comparatively discussed in view of materials development. Finally, the perspective and current challenges of polysaccharide nanocrystals in future functional nanomaterials are outlined.