Silica surface-modified with proteins

Figu re 4.8 Flow cytometry analysis of silica nanoparticles surface-modified with proteins. MPMS nanoparticles (a, c) and TEOS nanoparticles (b, d) modified with GFP (a, b) or phycoerythrin-conjugated streptavidin... 

Porous silica packings do, however, sometimes suffer from adsorption between the sample and silanol groups on the silica surface. This interaction can interfere with the size exclusion experiment and yield erroneous information. In many cases, this problem is easily overcome by selecting mobile phases that eliminate these interactions. In addition, the surface of porous silica packings is routinely modified in order to reduce these undesirable interactions. Trimeth-ylsilane modified packing is typically used with synthetic polymers. Diol modified packing is typically used with proteins and peptides. 

The major problem with proteins in HPCE is their tendency to adsorb to the silica surface. This can be minimized or prevented by modifying the... 

The other possibility is to coat the silica with a polymer of defined properties (molecular weight and distribntion) and olefin groups, e.g., polybutadiene, and cross-linked either by radiation or with a radical starter dissolved in the polymer [32]. This method is preferentially used when other carriers like titania and zirconia have to be surface modified. Polyethylenimine has been cross-linked at the snrface with pentaerythrolglycidether [41] to yield phases for protein and peptide chromatography. Polysiloxanes can be thermally bonded to the silica surface. Other technologies developed in coating fnsed silica capillaries in GC (polysiloxanes with SiH bonds) can also be applied to prepare RP for HPLC. 

Gilges, M., Hasmann, H., Kleemib, M. H., Motsch, S. R., and Schomburg, G. CZE separations of basic proteins at low pH in fused silica capillaries with surfaces modified by silane derivitization and/or adsorption of polar polymers, /. High Resolut. Chromatogr., 15, 452, 1992. 

There are, at least, three reasons responsible for diminution of the hemolytic effect on interaction of RBCs with TMS/A-300 (i) strong aggregation of partially hydrophobic silica particles and diminution of the amounts of individual primary silica nanoparticles, which are maximum bioactive, that causes diminution of the total contact area between RBCs and silica (per gram of silica) and a decrease of local interaction of solid particles with membrane proteins, (ii) changes in interaction energy between modified silica surface and the membrane structures due to a decrease in... 

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