Silicon biological function

In each of these formulas additional free OH groups are available on the silicon so that it is possible to crosslink more than two polysaccharide chains. Silicon may function as a biological crosslinking agent in connective tissue. Silaffins, small polypeptides containing polyamine side chains of modified lysine residues, apparently initiate silica formation from silicic acid in diatoms.0... 

Each of these minerals participate in a variety of biologic functions and is necessary for normal metabolism. Other trace minerals essential to humans but for which deficiency states have not been recognized include nickel, vanadium, cobalt, and silicon (Table 66.2). 

Efforts to discover whether other elements might be essential intensified during the 1970s. Although it is believed that arsenic, nickel, silicon, and boron are probably essential to humans, it has been difficult to determine whether other minerals have specific biological functions in humans or other animals. 

In conclusion, the recombinant SslA is able to self-assemble in vitro onto Si surfaces into large monolayers. Consequently, it may be used for a biological functionalization of silicon surfaces as a geometrically and physicochemically precisely defined immobilization matrix. 

Li H-F, Han H-M, Wu Y-G, Xiao S-J (2010) Biological functionalization and patterning of porous silicon prepared by Pt-assisted chemical etching. Appl Surf Sci 256 4048—4051 Linford MR, Chidsey CED (1993) Alkyl monolayers covalently bonded to sihcon surfaces. J Am Chem Soc 115 12631-12632... 

Silicon is an essential element for animals (Carlisle, 1982). Silicon may function as a biological cross-linking agent and may contribute to the architecture and resilience of coimective tissue (Schwarz, 1973). It has also been documented that silicon is present as a silanolate, i.e., an ester-like derivative of silicic acid and plays a role in the structural organization of glycosaminoglycans and polyuronides (Schwarz, 1973). 

The quality of the experimental evidence for nutritional essentiality varies widely for the ultratrace elements. The evidence for the essentiality of three elements, iodine, molybdenum and selenium, is substantial and noncontroversial specific biochemical functions have been defined for these elements. The nutritional importance of iodine and selenium are such that they have separate entries in this encyclopedia. Molybdenum, however, is given very little nutritional attention, apparently because a deficiency of this element has not been unequivocally identified in humans other than individuals nourished by total parenteral nutrition or with genetic defects causing disturbances in metabolic pathways involving this element. Specific biochemical functions have not been defined for the other 15 ultratrace elements listed above. Thus, their essentiality is based on circumstantial evidence, which most often is that a dietary deprivation in an animal model results in a suboptimal biological function that is preventable or reversible by an intake of physiological amounts of the element in question. Often the circumstantial evidence includes an identified essential function in a lower form of life, and biochemical actions consistent with a biological role or beneficial action in humans. The circumstantial evidence for essentiality is substantial for arsenic, boron, chromium, nickel, silicon, and vanadium. The evidence for essentiality for the... 

The benefit of the LbL technique is that the properties of the assemblies, such as thickness, composition, and function, can be tuned by varying the layer number, the species deposited, and the assembly conditions. Further, this technique can be readily transferred from planar substrates (e.g., silicon and quartz slides) [53,54] to three-dimensional substrates with various morphologies and structures, such as colloids [55] and biological cells [56]. Application of the LbL technique to colloids provides a simple and effective method to prepare core-shell particles, and hollow capsules, after removal of the sacrificial core template particles. The properties of the capsules prepared by the LbL procedure, such as diameter, shell thickness and permeability, can be readily adjusted through selection of the core size, the layer number, and the nature of the species deposited [57]. Such capsules are ideal candidates for applications in the areas of drug delivery, sensing, and catalysis [48-51,57]. 

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