Molecular organization and aggregation of mucin at air–water interface in the presence of chromium(III) complexes

The interfacial organization of mucin (glycoprotein) in the presence of chromium(III) complexes has been assessed from the surface pressure–molecular area (π–A) isotherms in Langmuir films at air–water interface and the surface energy of their LB films through contact angle measurements. At pH 7.0, the electrostatic interaction of [Cr(en)3]Cl3 with mucin was found to bring about changes in the average surface area from 3.26 to 1.47 nm2; suggesting the possible formation of large aggregates of mucin. Adsorption experiments using surface potential measurements reveal that [Cr(en)3]Cl3 binds at a much faster rate to the available binding sites in mucin when compared to [Cr(salen)(H2O)2](ClO4) which binds coordinatively to mucin.