IngentaConnect Assemblies of Concanavalin A onto Carboxymethylcellulose

Authors: Castro, Lizandra B.R.; Petri, Denise F.S.

Source: Journal of Nanoscience and Nanotechnology, Volume 5, Number 12, December 2005 , pp. 2063-2069(7)

Publisher: American Scientific Publishers

Abstract:

The immobilization of Concanavalin A, (Con A), onto flat surfaces formed by ultrathin films of carboxymethylcellulose, CMC, silicon wafers or spin-coated poly(methyl methacrylate), (PMMA), was studied by ellipsometry, contact angle measurements and atomic force microscopy (AFM). The formation of Con A monolayer was only observed onto CMC films. The adsorption constant of Con A onto CMC films was determined as being (2.1±0.2) × 10⁶ L mol⁻¹. After assembling Con A onto CMC surfaces, these became more hydrophobic, indicating a molecular orientation of Con A hydrophilic residues to the polysaccharide and Con A hydrophobic residues to the air. The affinity of Con A for hydroxyl rich silicon surfaces or for more hydrophobic PMMA films was very weak, evidencing that nonspecific interactions play a marginal role. For comparison, the immobilization of Con A onto hybrid particles of PMMA/CMC was investigated by means of UV-spectrophotometry. Such particles carry CMC chains attached to the surface, as evidenced by mean zeta potential value of −40 mV. The adsorption constant determined for Con A onto PMMA/CMC particles was one order of magnitude smaller than that found for Con A onto CMC films. This finding indicates that the substrate geometry might influence the molecular arrangement of sugar residues on the surface, consequently affecting the sugar-Con A interaction (cluster effect).

Keywords: CONCANAVALIN A; CARBOXYMETHYLCELLULOSE; THIN FILMS; HYBRID PARTICLES ELLIPSOMETRY

Document Type: Research article

DOI: 10.1166/jnn.2005.501

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