Proteins surface imprinting

Tan CJ, Tong YW (2007) Preparation of superparamagnetic ribonuclease a surface-imprinted submicrometer particles for protein recognition in aqueous media. Anal Chem 79 299-306... 

Nonspherical, surface-imprinted magnetic PMMA (see Fig. 28) nanoparticles could be prepared by Tan et al. [177, 178]. A miniemulsion process was used to prepare magnetite/PMMA nanoparticles on which proteins were either immobilized by adsorption (RNAse A) [178] or covalently (bovine serum albumin, BSA) [177]. After creating a shell of PMMA, the proteins were removed, leaving cavities on the particles surface. The BSA-imprinted nanoparticles showed superparamagnetic properties and exhibited a high rebinding capacity for BSA. 

There has been work by various groups devoted to this surface imprinting [63-72]. Silica [63-65] and polymer [66,71] particles had been modified, so that polymerizable groups were available which could react during a homogeneously initiated polymerization (see Scheme 4a). Particles had been imprinted also for the recognition of proteins [67,68]. 

Hence, building on this approach, part of the protein of interest, an epitope, has been surface imprinted, instead of the whole, and the resulting binding sites were successfully used to capture the whole protein by recognition of the imprinted part (Fig. 4). In both cases, silica beads, membrane pores, or nanowire surfaces have been used as sacrificial supports and were easily removed by dissolution after polymerization occurred. 

Fig. 3 Schematic representation of surface imprinting of a protein 1, protein immobilization on the surface 2, surface polymerization 3, removal of initial surface and template 4, protein rebinding.

Fig. 4 Schematic representation of epitope imprinting 1, epitope attachment on the siurface 2, surface imprinting of the epitope 3, removal of the initial surface and template 4, binding of the epitope-containing protein.

Zhang, M. Huang, J. Yu, P. Chen, X. (2010). Preparation and characteristics of protein molecularly imprinted membranes on the surface of multiwalled carbon nanotubes. Talanta, 81,162-166. 

A. Menaker, V. Syritski, J. Reut, A. Opik, V. Horvdth, and R. E. Gyurcsanyi, Electrosynthesized surface-imprinted conducting polymer microrods for selective protein recognition, Adv. Mater., 21, 2271-227, 2009. 

It must be emphasized here that the protein surface clefts have no particular common shape. They are neither concave nor do they look like an imprint of the substrate or co-enzyme. "Fitting" just means the size of the gap is large enough for the substrate and the orientation of polar and apolar regions correspond positively to each other. 

Capture array Non-protein molecules that interact with proteins are immobilized on the surface. These may be broad capture agents based on surface chemistries such as the Ciphergen Protein Chip, or may be highly specific such as molecular imprinted polymers or oligonucleotide aptamers... 

ORMOSIL are chemical sponges they adsorb and concentrate reactants at their surface, thereby enhancing reaction rates and sensitivity (in sensing applications). ORMOSIL-imprinted materials with a suitable chiral template such as a surfactant or a protein selectively adsorb (and detect) external reactants. A remarkable example is provided by thin materials that are generally enantioselective, namely where the chirally imprinted cavities can discriminate between enantiomers of molecules not used in the imprinting process, and completely different from the imprinting ones. 

Bossi A, Piletsky SA, Piletska EV, Righetti PG, Turner AP. Surface-grafted molecularly imprinted polymers for protein recognition. Anal Chem 2001 73 5281-5286. 

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