Protein Density Gradients on Surfaces

Abstract

Gradients of biologically active proteins can be obtained by applying photochemical reactions. A photosensitive polysaccharide-based polymer (OptoDex) is used to covalently immobilize proteins on surfaces. Gradients of proteins are generated by varying the dose of light during the photoimmobilization. Probe proteins conserve their catalytic activity or immunological binding characteristics when linked to surfaces exemplified by silicon nitride or polystyrene. Heterogeneous immunoreactions between photoimmobilized antigens and antibodies showed an optimum binding efficiency at an antigen density of approximatly 1.3 ng/mm2.

Microarray Technology as a Universal Tool for High-Throughput Analysis of Biological Systems

“…2) [46][47][48]. Hydrogels based on polyacrylic acid derivatives and other gel forming compounds such as dextranes and cellulose derivatives contain a large amount of water thus providing a convenient environment with solution-like properties preserving protein function [19,49,50]. Moreover, the extended 3D network allows for efficient immobilization of a higher number of probe molecules compared to planar 2D surfaces [17].…”

“…Those include a protected isocyanate group [15], diazobenzylidene [16], azidobenzoate attached to poly-L-lysine [17], diazirin derivatives [18,19], and azide [20].…”

“…New methods of protein microarray production include a sol-gel based process [66], the spotting of a protein in a mixture with a photolinker polymer followed by immobilization via a UV light induced carbene reaction [19], and the preparation of a 3D matrix using a monomer with anchored protein [67]. Acrylic acid modified proteins mixed with a suitable co-monomer and a crosslinker were subjected to a radical polymerization by Mirzabekov et al The reaction was performed by spotting the mixture to a silane modified surface and subsequent polymerization under UV light irradiation resulting in a gel with the protein immobilized.…”

Stimuli-responsive command polymer surface for generation of protein gradients

“…17,18 The gradient surfaces have been used to tune the protein adsorption and, consequently, cell adhesion 13 to study both the effect of ligand/receptor density on biological recognition 19,20 and polyvalency. 21 A number of approaches for the gradient of surface density of proteins have been proposed, such as varying the dose of light during the protein photoimmobilization, 22 using nanoparticles as protein carriers and optical tags, 23 adsorption on the gradient selfassembled monolayers ͑SAMs͒ or surface immobilized polymer layers, 14 ink-jet method, 24 and the depletion effect in the fluid. 25 The methods of gradient fabrication have gained considerable attention in recent reviews.…”

Surface-chemical and -morphological gradients

“…Gradients have also been prepared directly from immunoglobulin G (IgG) by gradual immobilisation. 79,89 The efficiency of the antibody-antigen interaction on such IgG density gradients depends on the antigen surface density. An optimum surface density was found for both types of gradient.…”