Silica-protein composite materials

A considerable amount of work has been directed at understanding the influences of the silica environment on dopant molecules, due the importance of these effects on the behavior of the composite materials. Much of this work has been performed using organic dyes as probes of the sol-gel interior, which continue to provide a wealth of useful information (83). Detailed study of proteins has also given considerable insight (16, 26, 28, 29). 

SynChropak was the first commercial bonded silica of this type, followed by LIChrosorb DIOL and LiChrospher DIOL. Protein-Pak materials as well as Sl-Polyol are similar in surface composition. Recently a specifically pH-stabIIized, glycerol-bonded silica has been introduced on the market Zorbax Bio-Series 6F 250. The most popular are the TSK gel SW types which are thought to be bonded with a glycerol-ether moiety. On annealing from 400 to 823 K, the TSK gel SW 3000 showed a weight loss of ca. 15X while the carbon content was 7.3X, Indicating on oxygen-rich... 

Separation by composition has been performed not only on silica but also on nonpolar carbonaceous materials and on bonded-phase packings of moderate polarity. The reversed-phase separation of biopolymers, especially of proteins, has gained great importance and is well-known to chromatographers and life scientists. What else should protein mapping be if not separation by composition An example,5) of this important technique is given in Fig. 5. 

Recently, Foo et al. (2006) produced some novel nanocomposites from spider silk-silica fusion (chimeric) proteins. The composite morphology and structure could be regulated by controlling processing conditions to produce films and fibers. Silk and biomineralization being natural inspiration sources will allow production of numerous new materials in various fields of application. 

Table V surveys commercial hydrophilic bonded silicas and columns, characterized by the trade name, the chemical composition where known, the available grades together with the molecular weight separation range for native globular proteins, the mean particle diameter, and the column dimensions. There are several identical materials marketed by various suppliers under different trade names.

One way to overcome the issue of leaching is to entrap species that are so physically large that it is difficult or impossible for them to leach from the matrix. Wallace et al. [15] were able to entrap within silica aerogels protein superstructures of cytochrome c cyt c) around gold nanoparticles. They demonstrated the apphcabihty of these materials for gas-phase NO sensing. The size of the cyt c superstructures is such that the resulting material can be considered a composite consequently, this work is described in more detail in Sect. 27.2.6. 

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