Coatings, surface-modifying additives

All the pre-coating methods in use rely on the addition of a fixed amoimt of surface modifier to a given amoimt of filler, thus determining the final composition. It is thus necessary to know in advance how much coating to use for a given apphcation. 

One of the first steps in modifying the performance of capillary electrophoresis was the deactivation of silica groups of the capillary column by physically coating the capillary wall with methylcellulose (58,59), as well as via silane derivatization (10,44,60). Presently, many other changes have been carried out either to the capillary surface or addition of chemical agents to the separation buffer (see Table II), including manipulation of... 

Porous structure of the outer support surface has been modified by deposition of the additional layer of metal Ni. Two vacuum condensation techniques have been used for nickel deposition dc ion magnetron sputtering and electron beam evaporation. To produce coatings on tubes additional installation for dc sputtering has been designed. 

Besides the classical polymer introduced by Merrifield (1%-crosslinked chloromethylated polystyrene), a broad variety of polymeric supports is available for SPPS and some of the most popular resins are summarized in Table 1. The chemical structures of some selected resins are presented in Figure 1 and electron micrographs of several examples are displayed in Figure 2. In addition to the solid supports listed in Table 1, there are several other carriers used in peptide synthesis such as the gel-type and macroporous poly(meth-acrylates), coated surfaces like polystyrene films on polyethylene (PEt) sheets, polystyrene-coated polyethylene or polytetrafluoroethylene, and modified glass surfaces. (For recent reviews on polymeric carriers see refs . )... 

In the specific case of zirconia-silica composites, the stationary phase could be prepared through relatively simple processes using either coprecipitation or coating methods. The addition of silica to the zirconia matrix increases the phase transition temperature from the amorphous phase to the tetragonal phase, which in turn stabilizes the tetragonal phase. The pore structure can be controlled through processes similar to those employed in the preparation of zirconia. However, the type of pore structure obtained appears to be dependent on the method of preparation. Calcination in the presence of salts improves the pore shapes. Zirconia-silica phases can also be surface-modified and Cg and ion-exchange media have been prepared. Composite zirconia-silica stationary... 

Fig. 10 Subsequent additions of biotin-BSA (i), lipid vesicles (ii), NeutrAvidin (in), single-stranded biotin-DNA (iv), and lipid vesicles modified with fully complementary DNA (v) to a Si02-coated and b Au-coated QCM crystals. Note that there is no adsorption of biotin-BSA on Si02, while the efficient binding of biotin-BSA on An significantly reduces vesicles adsorption to the Au-coated surface. Similarly, the bilayer formation renders the Si02-coated surface inert to subsequent additions of DNA and vesicles. The micrograph shows sequence-specific sorting of two differently fluorescently labeled DNA-modified vesicles to spots modified with different DNA sequences...

The other bioactive polysaccharide that seemed interesting to be used to produce surface-modified nanoparticles reducing their recognition by the host defense was heparin. Heparin is used as a drug for its anticoagulation properties. Additionally, it is an inhibitor of the complement activation phenomenon [116-118]. It was demonstrated that heparin-coated nanoparticles did not activate the complement system [19, 31, 32] and remained in the blood stream for a longer time compared with nanoparticles, which do not show heparin on the nanoparticle surface [89], Other polysaccharides extracted from mushrooms were found to inhibit the activation process of the complement. They could be alternative polysaccharides to produce nanoparticles with a reduced capacity to activate the complement, such as heparin [119],... 

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