silicon and glucose-1-phosphate

Amylose brushes were synthesized by enzymatic polymerization with glucose-1-phosphate as monomer and rabbit muscle phosphorylase b as catalyst on gold-covered surfaces of a quartz crystal microbalance. Fourier transform infrared (FT-IR) spectra confirmed the presence of the characteristic absorption peaks of amylose between 3100 cm(-1) and 3500 cm(-1). The thickness of the amylose brushes-measured by Spectroscopic Ellipsometry--can be tailored from 4 to 20 nm, depending on the reaction time. The contour length of the stretched amylose chains on gold surfaces has been evaluated by single molecule force spectroscopy, and a total chain length of about 20 nm for 16.2 nm thick amylose brushes was estimated. X-ray photoelectron spectroscopy (XPS) was employed to characterize the amylose brushes before and after the adsorption of fatty acids. The dynamics of inclusion complex formation between amylose brushes and two fatty acids (octanoic acid and myristic acid) with different chain length was investigated as a function of time using a quartz crystal microbalance with dissipation monitoring (QCM-D) immersed in the liquid phase. QCM-D signals including the frequency and dissipation shifts elucidated the effects of the fatty acid concentration, the solvent types, the chain length of the fatty acids and the thickness of the amylose brushes on the dynamics of fatty acid molecule adsorption on the amylose brush-modified sensor surfaces.

Topics: Amylose; Animals; Biocatalysis; Carbohydrate Conformation; Glucosephosphates; Glycogen Phosphorylase, Muscle Form; Gold; Molecular Sequence Data; Muscle, Skeletal; Polymerization; Quartz Crystal Microbalance Techniques; Rabbits; Silicon; Spectroscopy, Fourier Transform Infrared; Surface Properties; Thermodynamics; Time Factors

Densely packed polysaccharide brushes consisting of α-D-glucose residues were grafted from modified silicon substrates. Potato phosphorylase was herein used to grow linear polysaccharide chains from silicon tethered maltoheptaose oligosaccharides using glucose-1-phosphate as donor substrate. The combined use of potato phosphorylase and Deinococcusgeothermalis branching enzyme resulted in a hyperbranched brush coating as the latter one redistributes short oligosaccharides from the α(1-4)-linked position to the α (1-6)-linked position in the polysaccharide brush. The obtained grafting density of the brushes was estimated on 1.89 nm(-2) while the thickness was measured with ellipsometric techniques and determined to be between 12.2 and 20.2 nm.

Topics: 1,4-alpha-Glucan Branching Enzyme; Adsorption; Biocompatible Materials; Biomimetic Materials; Deinococcus; Glucans; Glucosephosphates; Glycocalyx; Humans; Phosphorylases; Photoelectron Spectroscopy; Prostheses and Implants; Silicon