Spectroscopic ellipsometry of mucin layers on an amphiphilic diblock copolymer surface

Both visible and infrared (IR) spectroscopic ellipsometry have been employed to study the structure of thin layers of bovine submaxillary mucin (BSM) adsorbed on poly(acrylic acid-block-methyl methacrylate) (PAA-b-PMMA) copolymer and poly(methyl methacrylate) (PMMA) surfaces at three pH values (3, 7, and 10). The adsorbed mucin layer on the copolymer surface had the greatest thickness (17 nm) when adsorbed from a mucin solution at a pH of 3. For the first time, IR ellipsometry was used to identify adhesive interactions and conformational changes in mucin/polymer double layers. After applying the regularized method of deconvolution in the analysis, the formation of hydrogen bonds between the carboxyl groups of the BSM and PAA-b-PMMA copolymer in double layers has been found. The IR ellipsometry data, in agreement with the visible ellipsometry analysis, indicate the pH dependence of adhesion of mucin to the copolymer surface. There is an increase in the amount of hydrogen-bonded carboxyl groups in mucin deposited at a pH of 3. There is no evidence that the amide groups of the mucin participate in this bonding. At the lower pH, the IR ellipsometry spectra after deconvolution reveal an increase in the proportion of β-sheets in the BSM upon adsorption on the copolymer surface, indicating a more unfolded, aggregated structure. The IR ellipsometry data also indicated some changes in the conformational states of the side groups in the copolymer induced by entanglements and bonding interactions with the mucin macromolecules. Deconvolution provides an unprecedented level of information from the IR ellipsometry spectra and yields important insights. © 2009 Society for Applied Spectroscopy

Spectroscopic ellipsometry of mucin layers on an amphiphilic diblock copolymer surface

Both visible and infrared (IR) spectroscopic ellipsometry have been employed to study the structure of thin layers of bovine submaxillary mucin (BSM) adsorbed on poly(acrylic acid-block-methyl methacrylate) (PAA-b-PMMA) copolymer and poly(methyl methacrylate) (PMMA) surfaces at three pH values (3, 7, and 10). The adsorbed mucin layer on the copolymer surface had the greatest thickness (17 nm) when adsorbed from a mucin solution at a pH of 3. For the first time, IR ellipsometry was used to identify adhesive interactions and conformational changes in mucin/polymer double layers. After applying the regularized method of deconvolution in the analysis, the formation of hydrogen bonds between the carboxyl groups of the BSM and PAA-b-PMMA copolymer in double layers has been found. The IR ellipsometry data, in agreement with the visible ellipsometry analysis, indicate the pH dependence of adhesion of mucin to the copolymer surface. There is an increase in the amount of hydrogen-bonded carboxyl groups in mucin deposited at a pH of 3. There is no evidence that the amide groups of the mucin participate in this bonding. At the lower pH, the IR ellipsometry spectra after deconvolution reveal an increase in the proportion of β-sheets in the BSM upon adsorption on the copolymer surface, indicating a more unfolded, aggregated structure. The IR ellipsometry data also indicated some changes in the conformational states of the side groups in the copolymer induced by entanglements and bonding interactions with the mucin macromolecules. Deconvolution provides an unprecedented level of information from the IR ellipsometry spectra and yields important insights. © 2009 Society for Applied Spectroscopy

Adhesion of microorganisms to bovine submaxillary mucin coatings: effect of coating deposition conditions

The adhesion of Staphylococcus epidermidis, Escherichia coli, and Candida albicans on mucin coatings was evaluated to explore the feasibility of using the coating to increase the infection resistance of biomaterials. Coatings of bovine submaxillary mucin (BSM) were deposited on a base layer consisting of a poly(acrylic acid-b-methyl methacrylate) (PAA-b-PMMA) diblock copolymer. This bi-layer system exploits the mucoadhesive interactions of the PAA block to aid the adhesion of mucin to the substratum, whereas the PMMA block prevents dissolution of the coating in aqueous environments. The thickness of the mucin coating was adjusted by varying the pH of the solution from which it was deposited. Thin mucin coatings decreased the numbers of bacteria but increased the numbers of C. albicans adhering to the copolymer and control surfaces. Increasing the mucin film thickness resulted in a further lowering of the density of adhering S. epidermidis cells, but it did not affect the density of E. coli. In contrast, the density of C. albicans increased with an increase in mucin thickness

Adhesion of microorganisms to bovine submaxillary mucin coatings: effect of coating deposition conditions

The adhesion of Staphylococcus epidermidis, Escherichia coli, and Candida albicans on mucin coatings was evaluated to explore the feasibility of using the coating to increase the infection resistance of biomaterials. Coatings of bovine submaxillary mucin (BSM) were deposited on a base layer consisting of a poly(acrylic acid-b-methyl methacrylate) (PAA-b-PMMA) diblock copolymer. This bi-layer system exploits the mucoadhesive interactions of the PAA block to aid the adhesion of mucin to the substratum, whereas the PMMA block prevents dissolution of the coating in aqueous environments. The thickness of the mucin coating was adjusted by varying the pH of the solution from which it was deposited. Thin mucin coatings decreased the numbers of bacteria but increased the numbers of C. albicans adhering to the copolymer and control surfaces. Increasing the mucin film thickness resulted in a further lowering of the density of adhering S. epidermidis cells, but it did not affect the density of E. coli. In contrast, the density of C. albicans increased with an increase in mucin thickness