Surface imprinting functionalization

Fig. 8.7. Surface imprinting with a covalently coupled diimine template has been used to position two amines onto a flat silica surface in an effort to isolate the effect of functional group placement in molecular imprinting. The rectangular spacer between the imines represents either a phenyl or diphenylmethane. Adapted from [37].

Another technique was proposed as an efficient method for the preparation of surface-template resins. In surface imprinting, a functional surfactant (emulsilier) that is capable of binding metal ions and functions as a vinyl monomer must orient at the interface between the matrix monomers and water and emulsify the mixture. 

A report by Lulka and Chambers [27] describes the properties of surface-imprinted silicas using A-acetyltryptophanamide (NATA) or fluorescein (Fig. 20.9) as templates. Silica gel was mixed with bis(2-hydroxyethyl)-aminopropyltriethoxysi-lane (as functional monomer), tetraethoxysilane and the template and the slurry... 

Phenylphosphonic acid Tetraethoxysilane-based gel EtOH 1-trimethoxysilyl-propyl-3-guanidium chloride or 3-trimethoxysilylpropyl-1-trimethylammonium chloride Surface imprinting on silica xerogels guanidium or ammonium surface-functional zation solid-state 31P NMR characterization [125]... 

The same types of surface-imprinted polymers were also used to discriminate between the enantiomers of bifunctional amino acids [24]. In this study, the functional host molecule was the quaternary ammonium salt and the templates were the A -protected amino acids shown in Fig. 5. 

Surface imprinting of latex particles is an approach to use functional groups present on the surface of a polymer and fix their conformation by a surface modification with another polymer [84,85]. An attempt had been made to reduce the nonspecific binding by applying a hydrophilic coating after the MIP preparation [86]. 

By a surface imprinting technique, in Zhang H. et al., 2011, a comfX)site imprinted material, on the basis of a MWCNTs-incorporated layer using melamine as a template, methacrylic acid as a functional monomer, and ethylene glycol dimethaciylate as a cross-linker, was synthesized. In this work, the poly(acrylic-acid)-functionalized CNTs were synthesized to increase the diameter of CNTs. Then, the vinyl group was introduced to the surface of poly(acrylic-acid)-functionalized CNTs by an amidation Using Melamine as a template molecule, imprinted CNT composite material was fabricated by a thermal fX)lymeiization. Applied as a sorbent, the imprinted materials were used for the determination of Melamine in the spiked sample by online SPE combined with HPLC. 

Shi, F. Liu, Z. Wu, G. Zhang, M. Chen, H. Wang, Z. Zhang, X. Willner, I. (2007). Surface Imprinting in Layer-by-Layer Nanostructured Films. Advanced Functional Materials, 17,1821-1827. 

A general approach to prepare hollow spheres of ceramic materials with func-tionaUzed interior surface has also been reported [121]. The onter surfaces of the templating PS beads are first coated with submonolayers of silver nanoparlicles, and they are assembled into a three-dimensional crystalline lattice. The beads are then coated with a titania layer. After the PS beads are dissolved in toluene, uniform hollow spheres are generated, with their interior surfaces being functionalized with the silver nanoparticles. Meanwhile, silver nanoparticles can be selectively removed using another wet etchant to produce an array of nanosized cavities on the interior surface of the hollow sphere. These nanoscale cavities may have functionality similar to that of the nanoscale template, as demonstrated in the area of molecular imprinting [122,123]. 

Capture array involves the immobilization of non-protein molecules onto the surface which can interact with proteins in the solute phase. Generally, capture molecules may be broad capture agents based on chromatography type surface chemistries such as ion exchange, hydrophobic and metal affinity functionality, or they may be highly specific such as molecular imprinted polymers or oligonucleotide aptamers. 

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